Misc¶

ACLs¶

swift.common.middleware.acl.acls_from_account_info(info)¶

Extract the account ACLs from the given account_info, and return the ACLs.

Parameters:	info – a dict of the form returned by get_account_info
Returns:	None (no ACL system metadata is set), or a dict of the form:: {‘admin’: […], ‘read-write’: […], ‘read-only’: […]}
Raises:	ValueError – on a syntactically invalid header

swift.common.middleware.acl.clean_acl(name, value)¶

Returns a cleaned ACL header value, validating that it meets the formatting requirements for standard Swift ACL strings.

The ACL format is:

[item[,item...]]

Each item can be a group name to give access to or a referrer designation to grant or deny based on the HTTP Referer header.

The referrer designation format is:

.r:[-]value

The .r can also be .ref, .referer, or .referrer; though it will be shortened to just .r for decreased character count usage.

The value can be * to specify any referrer host is allowed access, a specific host name like www.example.com, or if it has a leading period . or leading *. it is a domain name specification, like .example.com or *.example.com. The leading minus sign - indicates referrer hosts that should be denied access.

Referrer access is applied in the order they are specified. For example, .r:.example.com,.r:-thief.example.com would allow all hosts ending with .example.com except for the specific host thief.example.com.

Example valid ACLs:

.r:*
.r:*,.r:-.thief.com
.r:*,.r:.example.com,.r:-thief.example.com
.r:*,.r:-.thief.com,bobs_account,sues_account:sue
bobs_account,sues_account:sue

Example invalid ACLs:

.r:
.r:-

By default, allowing read access via .r will not allow listing objects in the container – just retrieving objects from the container. To turn on listings, use the .rlistings directive.

Also, .r designations aren’t allowed in headers whose names include the word ‘write’.

ACLs that are “messy” will be cleaned up. Examples:

Original	Cleaned
`bob, sue`	`bob,sue`
`bob , sue`	`bob,sue`
`bob,,,sue`	`bob,sue`
`.referrer : *`	`.r:*`
`.ref:*.example.com`	`.r:.example.com`
`.r:*, .rlistings`	`.r:*,.rlistings`

Parameters:	name – The name of the header being cleaned, such as X-Container-Read or X-Container-Write. value – The value of the header being cleaned.
Returns:	The value, cleaned of extraneous formatting.
Raises:	ValueError – If the value does not meet the ACL formatting requirements; the error message will indicate why.

swift.common.middleware.acl.format_acl(version=1, **kwargs)¶

Compatibility wrapper to help migrate ACL syntax from version 1 to 2. Delegates to the appropriate version-specific format_acl method, defaulting to version 1 for backward compatibility.

Parameters:	kwargs – keyword args appropriate for the selected ACL syntax version (see `format_acl_v1()` or `format_acl_v2()`)

swift.common.middleware.acl.format_acl_v1(groups=None, referrers=None, header_name=None)¶

Returns a standard Swift ACL string for the given inputs.

Caller is responsible for ensuring that :referrers: parameter is only given if the ACL is being generated for X-Container-Read. (X-Container-Write and the account ACL headers don’t support referrers.)

Parameters:	groups – a list of groups (and/or members in most auth systems) to grant access referrers – a list of referrer designations (without the leading .r:) header_name – (optional) header name of the ACL we’re preparing, for clean_acl; if None, returned ACL won’t be cleaned
Returns:	a Swift ACL string for use in X-Container-{Read,Write}, X-Account-Access-Control, etc.

swift.common.middleware.acl.format_acl_v2(acl_dict)¶

Returns a version-2 Swift ACL JSON string.

HTTP headers for Version 2 ACLs have the following form:: Header-Name: {“arbitrary”:”json”,”encoded”:”string”}

JSON will be forced ASCII (containing six-char uNNNN sequences rather than UTF-8; UTF-8 is valid JSON but clients vary in their support for UTF-8 headers), and without extraneous whitespace.

Advantages over V1: forward compatibility (new keys don’t cause parsing exceptions); Unicode support; no reserved words (you can have a user named .rlistings if you want).

Parameters:	acl_dict – dict of arbitrary data to put in the ACL; see specific auth systems such as tempauth for supported values
Returns:	a JSON string which encodes the ACL

swift.common.middleware.acl.parse_acl(*args, **kwargs)¶

Compatibility wrapper to help migrate ACL syntax from version 1 to 2. Delegates to the appropriate version-specific parse_acl method, attempting to determine the version from the types of args/kwargs.

Parameters:	args – positional args for the selected ACL syntax version kwargs – keyword args for the selected ACL syntax version (see `parse_acl_v1()` or `parse_acl_v2()`)
Returns:	the return value of `parse_acl_v1()` or `parse_acl_v2()`

swift.common.middleware.acl.parse_acl_v1(acl_string)¶

Parses a standard Swift ACL string into a referrers list and groups list.

See clean_acl() for documentation of the standard Swift ACL format.

Parameters:	acl_string – The standard Swift ACL string to parse.
Returns:	A tuple of (referrers, groups) where referrers is a list of referrer designations (without the leading .r:) and groups is a list of groups to allow access.

swift.common.middleware.acl.parse_acl_v2(data)¶

Parses a version-2 Swift ACL string and returns a dict of ACL info.

Parameters:	data – string containing the ACL data in JSON format
Returns:	A dict (possibly empty) containing ACL info, e.g.: {“groups”: […], “referrers”: […]}
Returns:	None if data is None, is not valid JSON or does not parse as a dict
Returns:	empty dictionary if data is an empty string

swift.common.middleware.acl.referrer_allowed(referrer, referrer_acl)¶

Returns True if the referrer should be allowed based on the referrer_acl list (as returned by parse_acl()).

See clean_acl() for documentation of the standard Swift ACL format.

Parameters:	referrer – The value of the HTTP Referer header. referrer_acl – The list of referrer designations as returned by `parse_acl()`.
Returns:	True if the referrer should be allowed; False if not.

Buffered HTTP¶

Monkey Patch httplib.HTTPResponse to buffer reads of headers. This can improve performance when making large numbers of small HTTP requests. This module also provides helper functions to make HTTP connections using BufferedHTTPResponse.

Warning

If you use this, be sure that the libraries you are using do not access the socket directly (xmlrpclib, I’m looking at you :/), and instead make all calls through httplib.

class swift.common.bufferedhttp.BufferedHTTPConnection(host, port=None, strict=None, timeout=<object object>, source_address=None)¶

Bases: httplib.HTTPConnection

HTTPConnection class that uses BufferedHTTPResponse

response_class¶: alias of BufferedHTTPResponse

class swift.common.bufferedhttp.BufferedHTTPResponse(sock, debuglevel=0, strict=0, method=None)¶

Bases: httplib.HTTPResponse

HTTPResponse class that buffers reading of headers

nuke_from_orbit()¶

Terminate the socket with extreme prejudice.

Closes the underlying socket regardless of whether or not anyone else has references to it. Use this when you are certain that nobody else you care about has a reference to this socket.

swift.common.bufferedhttp.http_connect(ipaddr, port, device, partition, method, path, headers=None, query_string=None, ssl=False)¶

Helper function to create an HTTPConnection object. If ssl is set True, HTTPSConnection will be used. However, if ssl=False, BufferedHTTPConnection will be used, which is buffered for backend Swift services.

Parameters:

ipaddr – IPv4 address to connect to
port – port to connect to
device – device of the node to query
partition – partition on the device
method – HTTP method to request (‘GET’, ‘PUT’, ‘POST’, etc.)
path – request path
headers – dictionary of headers
query_string – request query string
ssl – set True if SSL should be used (default: False)

Returns:

HTTPConnection object

swift.common.bufferedhttp.http_connect_raw(ipaddr, port, method, path, headers=None, query_string=None, ssl=False)¶

Helper function to create an HTTPConnection object. If ssl is set True, HTTPSConnection will be used. However, if ssl=False, BufferedHTTPConnection will be used, which is buffered for backend Swift services.

Parameters:	ipaddr – IPv4 address to connect to port – port to connect to method – HTTP method to request (‘GET’, ‘PUT’, ‘POST’, etc.) path – request path headers – dictionary of headers query_string – request query string ssl – set True if SSL should be used (default: False)
Returns:	HTTPConnection object

Constraints¶

swift.common.constraints.FORMAT2CONTENT_TYPE = {‘xml’: ‘application/xml’, ‘plain’: ‘text/plain’, ‘json’: ‘application/json’}¶: Query string format= values to their corresponding content-type values

swift.common.constraints.check_delete_headers(request)¶

Validate if ‘x-delete’ headers are have correct values values should be positive integers and correspond to a time in the future.

Parameters:	request – the swob request object
Returns:	HTTPBadRequest in case of invalid values or None if values are ok

swift.common.constraints.check_dir(root, drive)¶

Verify that the path to the device is a directory and is a lesser constraint that is enforced when a full mount_check isn’t possible with, for instance, a VM using loopback or partitions.

Parameters:	root – base path where the dir is drive – drive name to be checked
Returns:	True if it is a valid directoy, False otherwise

swift.common.constraints.check_float(string)¶

Helper function for checking if a string can be converted to a float.

Parameters:	string – string to be verified as a float
Returns:	True if the string can be converted to a float, False otherwise

swift.common.constraints.check_metadata(req, target_type)¶

Check metadata sent in the request headers. This should only check that the metadata in the request given is valid. Checks against account/container overall metadata should be forwarded on to its respective server to be checked.

Parameters:	req – request object target_type – str: one of: object, container, or account: indicates which type the target storage for the metadata is
Returns:	HTTPBadRequest with bad metadata otherwise None

swift.common.constraints.check_mount(root, drive)¶

Verify that the path to the device is a mount point and mounted. This allows us to fast fail on drives that have been unmounted because of issues, and also prevents us for accidentally filling up the root partition.

Parameters:	root – base path where the devices are mounted drive – drive name to be checked
Returns:	True if it is a valid mounted device, False otherwise

swift.common.constraints.check_name_format(req, name, target_type)¶

Validate that the header contains valid account or container name.

Parameters:	req – HTTP request object name – header value to validate target_type – which header is being validated (Account or Container)
Returns:	A properly encoded account name or container name
Raises:	HTTPPreconditionFailed – if account header is not well formatted.

swift.common.constraints.check_object_creation(req, object_name)¶

Check to ensure that everything is alright about an object to be created.

Parameters:	req – HTTP request object object_name – name of object to be created
Returns:	HTTPRequestEntityTooLarge – the object is too large
Returns:	HTTPLengthRequired – missing content-length header and not a chunked request
Returns:	HTTPBadRequest – missing or bad content-type header, or bad metadata
Returns:	HTTPNotImplemented – unsupported transfer-encoding header value

swift.common.constraints.check_utf8(string)¶

Validate if a string is valid UTF-8 str or unicode and that it does not contain any null character.

Parameters:	string – string to be validated
Returns:	True if the string is valid utf-8 str or unicode and contains no null characters, False otherwise

swift.common.constraints.reload_constraints()¶: Parse SWIFT_CONF_FILE and reset module level global constraint attrs, populating OVERRIDE_CONSTRAINTS AND EFFECTIVE_CONSTRAINTS along the way.

swift.common.constraints.valid_api_version(version)¶

Checks if the requested version is valid.

Currently Swift only supports “v1” and “v1.0”.

swift.common.constraints.valid_timestamp(request)¶

Helper function to extract a timestamp from requests that require one.

Parameters:	request – the swob request object
Returns:	a valid Timestamp instance
Raises:	HTTPBadRequest – on missing or invalid X-Timestamp

Container Sync Realms¶

class swift.common.container_sync_realms.ContainerSyncRealms(conf_path, logger)¶

Bases: object

Loads and parses the container-sync-realms.conf, occasionally checking the file’s mtime to see if it needs to be reloaded.

clusters(realm)¶: Returns a list of clusters for the realm.

endpoint(realm, cluster)¶: Returns the endpoint for the cluster in the realm.

get_sig(request_method, path, x_timestamp, nonce, realm_key, user_key)¶

Returns the hexdigest string of the HMAC-SHA1 (RFC 2104) for the information given.

Parameters:	request_method – HTTP method of the request. path – The path to the resource. x_timestamp – The X-Timestamp header value for the request. nonce – A unique value for the request. realm_key – Shared secret at the cluster operator level. user_key – Shared secret at the user’s container level.
Returns:	hexdigest str of the HMAC-SHA1 for the request.

key(realm)¶: Returns the key for the realm.

key2(realm)¶: Returns the key2 for the realm.

realms()¶: Returns a list of realms.

reload()¶: Forces a reload of the conf file.

Direct Client¶

Internal client library for making calls directly to the servers rather than through the proxy.

exception swift.common.direct_client.DirectClientException(stype, method, node, part, path, resp, host=None)¶: Bases: swift.common.exceptions.ClientException

swift.common.direct_client.direct_delete_account(node, part, account, conn_timeout=5, response_timeout=15, headers=None)¶

swift.common.direct_client.direct_delete_container(node, part, account, container, conn_timeout=5, response_timeout=15, headers=None)¶

Delete container directly from the container server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response headers – dict to be passed into HTTPConnection headers
Raises:	ClientException – HTTP DELETE request failed

swift.common.direct_client.direct_delete_container_object(node, part, account, container, obj, conn_timeout=5, response_timeout=15, headers=None)¶

swift.common.direct_client.direct_delete_object(node, part, account, container, obj, conn_timeout=5, response_timeout=15, headers=None)¶

Delete object directly from the object server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name obj – object name conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response
Raises:	ClientException – HTTP DELETE request failed

swift.common.direct_client.direct_get_account(node, part, account, marker=None, limit=None, prefix=None, delimiter=None, conn_timeout=5, response_timeout=15, end_marker=None, reverse=None)¶

Get listings directly from the account server.

Parameters:

node – node dictionary from the ring
part – partition the account is on
account – account name
marker – marker query
limit – query limit
prefix – prefix query
delimiter – delimiter for the query
conn_timeout – timeout in seconds for establishing the connection
response_timeout – timeout in seconds for getting the response
end_marker – end_marker query
reverse – reverse the returned listing

Returns:

a tuple of (response headers, a list of containers) The response headers will HeaderKeyDict.

swift.common.direct_client.direct_get_container(node, part, account, container, marker=None, limit=None, prefix=None, delimiter=None, conn_timeout=5, response_timeout=15, end_marker=None, reverse=None)¶

Get container listings directly from the container server.

Parameters:

node – node dictionary from the ring
part – partition the container is on
account – account name
container – container name
marker – marker query
limit – query limit
prefix – prefix query
delimiter – delimiter for the query
conn_timeout – timeout in seconds for establishing the connection
response_timeout – timeout in seconds for getting the response
end_marker – end_marker query
reverse – reverse the returned listing

Returns:

a tuple of (response headers, a list of objects) The response headers will be a HeaderKeyDict.

swift.common.direct_client.direct_get_object(node, part, account, container, obj, conn_timeout=5, response_timeout=15, resp_chunk_size=None, headers=None)¶

Get object directly from the object server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name obj – object name conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response resp_chunk_size – if defined, chunk size of data to read. headers – dict to be passed into HTTPConnection headers
Returns:	a tuple of (response headers, the object’s contents) The response headers will be a HeaderKeyDict.
Raises:	ClientException – HTTP GET request failed

swift.common.direct_client.direct_get_suffix_hashes(node, part, suffixes, conn_timeout=5, response_timeout=15, headers=None)¶

Get suffix hashes directly from the object server.

Parameters:	node – node dictionary from the ring part – partition the container is on conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response headers – dict to be passed into HTTPConnection headers
Returns:	dict of suffix hashes
Raises:	ClientException – HTTP REPLICATE request failed

swift.common.direct_client.direct_head_container(node, part, account, container, conn_timeout=5, response_timeout=15)¶

Request container information directly from the container server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response
Returns:	a dict containing the response’s headers in a HeaderKeyDict
Raises:	ClientException – HTTP HEAD request failed

swift.common.direct_client.direct_head_object(node, part, account, container, obj, conn_timeout=5, response_timeout=15, headers=None)¶

Request object information directly from the object server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name obj – object name conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response headers – dict to be passed into HTTPConnection headers
Returns:	a dict containing the response’s headers in a HeaderKeyDict
Raises:	ClientException – HTTP HEAD request failed

swift.common.direct_client.direct_post_object(node, part, account, container, name, headers, conn_timeout=5, response_timeout=15)¶

Direct update to object metadata on object server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name name – object name headers – headers to store as metadata conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response
Raises:	ClientException – HTTP POST request failed

swift.common.direct_client.direct_put_container_object(node, part, account, container, obj, conn_timeout=5, response_timeout=15, headers=None)¶

swift.common.direct_client.direct_put_object(node, part, account, container, name, contents, content_length=None, etag=None, content_type=None, headers=None, conn_timeout=5, response_timeout=15, chunk_size=65535)¶

Put object directly from the object server.

Parameters:	node – node dictionary from the ring part – partition the container is on account – account name container – container name name – object name contents – an iterable or string to read object data from content_length – value to send as content-length header etag – etag of contents content_type – value to send as content-type header headers – additional headers to include in the request conn_timeout – timeout in seconds for establishing the connection response_timeout – timeout in seconds for getting the response chunk_size – if defined, chunk size of data to send.
Returns:	etag from the server response
Raises:	ClientException – HTTP PUT request failed

swift.common.direct_client.gen_headers(hdrs_in=None, add_ts=False)¶

swift.common.direct_client.retry(func, *args, **kwargs)¶

Helper function to retry a given function a number of times.

Parameters:	func – callable to be called retries – number of retries error_log – logger for errors args – arguments to send to func kwargs – keyward arguments to send to func (if retries or error_log are sent, they will be deleted from kwargs before sending on to func)
Returns:	result of func
Raises:	ClientException – all retries failed

Exceptions¶

exception swift.common.exceptions.APIVersionError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.ChunkReadError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.ChunkReadTimeout(seconds=None, exception=None)¶: Bases: eventlet.timeout.Timeout

exception swift.common.exceptions.ChunkWriteTimeout(seconds=None, exception=None)¶: Bases: eventlet.timeout.Timeout

exception swift.common.exceptions.ClientException(msg, http_scheme=”, http_host=”, http_port=”, http_path=”, http_query=”, http_status=None, http_reason=”, http_device=”, http_response_content=”, http_headers=None)¶: Bases: exceptions.Exception

exception swift.common.exceptions.ConnectionTimeout(seconds=None, exception=None)¶: Bases: eventlet.timeout.Timeout

exception swift.common.exceptions.DeviceUnavailable¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.DiskFileCollision¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileDeleted(metadata=None)¶: Bases: swift.common.exceptions.DiskFileNotExist

exception swift.common.exceptions.DiskFileDeviceUnavailable¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.DiskFileExpired(metadata=None)¶: Bases: swift.common.exceptions.DiskFileDeleted

exception swift.common.exceptions.DiskFileNoSpace¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileNotExist¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileNotOpen¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileQuarantined¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DiskFileXattrNotSupported¶: Bases: swift.common.exceptions.DiskFileError

exception swift.common.exceptions.DriveNotMounted¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.DuplicateDeviceError¶: Bases: swift.common.exceptions.RingBuilderError

exception swift.common.exceptions.EmptyRingError¶: Bases: swift.common.exceptions.RingBuilderError

exception swift.common.exceptions.EncryptionException¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.FileNotFoundError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.FooterNotSupported¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.InsufficientStorage¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.InvalidAccountInfo¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.InvalidPidFileException¶: Bases: exceptions.Exception

exception swift.common.exceptions.InvalidTimestamp¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.ListingIterError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.ListingIterNotAuthorized(aresp)¶: Bases: swift.common.exceptions.ListingIterError

exception swift.common.exceptions.ListingIterNotFound¶: Bases: swift.common.exceptions.ListingIterError

exception swift.common.exceptions.LockTimeout(seconds=None, msg=None)¶: Bases: swift.common.exceptions.MessageTimeout

exception swift.common.exceptions.MessageTimeout(seconds=None, msg=None)¶: Bases: eventlet.timeout.Timeout

exception swift.common.exceptions.MimeInvalid¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.MultiphasePUTNotSupported¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.PathNotDir¶: Bases: exceptions.OSError

exception swift.common.exceptions.PermissionError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.PutterConnectError(status=None)¶: Bases: exceptions.Exception

exception swift.common.exceptions.RangeAlreadyComplete¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.ReplicationException¶: Bases: exceptions.Exception

exception swift.common.exceptions.ReplicationLockTimeout(seconds=None, msg=None)¶: Bases: swift.common.exceptions.LockTimeout

exception swift.common.exceptions.ResponseTimeout(seconds=None, exception=None)¶: Bases: eventlet.timeout.Timeout

exception swift.common.exceptions.RingBuilderError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.RingLoadError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.RingValidationError¶: Bases: swift.common.exceptions.RingBuilderError

exception swift.common.exceptions.SegmentError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.SuffixSyncError¶: Bases: swift.common.exceptions.SwiftException

exception swift.common.exceptions.SwiftException¶: Bases: exceptions.Exception

exception swift.common.exceptions.UnPicklingError¶: Bases: swift.common.exceptions.SwiftException

Internal Client¶

class swift.common.internal_client.CompressingFileReader(file_obj, compresslevel=9, chunk_size=4096)¶

Bases: object

Wrapper for file object to compress object while reading.

Can be used to wrap file objects passed to InternalClient.upload_object().

Used in testing of InternalClient.

Parameters:	file_obj – File object to wrap. compresslevel – Compression level, defaults to 9. chunk_size – Size of chunks read when iterating using object, defaults to 4096.

next()¶

read(*a, **kw)¶

Reads a chunk from the file object.

Params are passed directly to the underlying file object’s read().

Returns:	Compressed chunk from file object.

seek(offset, whence=0)¶

set_initial_state()¶: Sets the object to the state needed for the first read.

class swift.common.internal_client.InternalClient(conf_path, user_agent, request_tries, allow_modify_pipeline=False)¶

Bases: object

An internal client that uses a swift proxy app to make requests to Swift.

This client will exponentially slow down for retries.

Parameters:	conf_path – Full path to proxy config. user_agent – User agent to be sent to requests to Swift. request_tries – Number of tries before InternalClient.make_request() gives up.

account_ring¶

auto_create_account_prefix¶

container_exists(account, container)¶

Checks to see if a container exists.

Parameters:	account – The container’s account. container – Container to check.
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.
Returns:	True if container exists, false otherwise.

container_ring¶

create_container(account, container, headers=None, acceptable_statuses=(2, ))¶

Creates container.

Parameters:	account – The container’s account. container – Container to create. headers – Defaults to empty dict. acceptable_statuses – List of status for valid responses, defaults to (2,).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

delete_container(account, container, acceptable_statuses=(2, 404))¶

Deletes a container.

Parameters:	account – The container’s account. container – Container to delete. acceptable_statuses – List of status for valid responses, defaults to (2, HTTP_NOT_FOUND).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

delete_object(account, container, obj, acceptable_statuses=(2, 404), headers=None)¶

Deletes an object.

Parameters:	account – The object’s account. container – The object’s container. obj – The object. acceptable_statuses – List of status for valid responses, defaults to (2, HTTP_NOT_FOUND). headers – extra headers to send with request
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

get_account_info(account, acceptable_statuses=(2, 404))¶

Returns (container_count, object_count) for an account.

Parameters:	account – Account on which to get the information. acceptable_statuses – List of status for valid responses, defaults to (2, HTTP_NOT_FOUND).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

get_account_metadata(account, metadata_prefix=”, acceptable_statuses=(2, ))¶

Gets account metadata.

Parameters:	account – Account on which to get the metadata. metadata_prefix – Used to filter values from the headers returned. Will strip that prefix from the keys in the dict returned. Defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,).
Returns:	Returns dict of account metadata. Keys will be lowercase.
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

get_container_metadata(account, container, metadata_prefix=”, acceptable_statuses=(2, ))¶

Gets container metadata.

Parameters:	account – The container’s account. container – Container to get metadata on. metadata_prefix – Used to filter values from the headers returned. Will strip that prefix from the keys in the dict returned. Defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,).
Returns:	Returns dict of container metadata. Keys will be lowercase.
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

get_object(account, container, obj, headers, acceptable_statuses=(2, ))¶: Returns a 3-tuple (status, headers, iterator of object body)

get_object_metadata(account, container, obj, metadata_prefix=”, acceptable_statuses=(2, ), headers=None)¶

Gets object metadata.

Parameters:	account – The object’s account. container – The object’s container. obj – The object. metadata_prefix – Used to filter values from the headers returned. Will strip that prefix from the keys in the dict returned. Defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,). headers – extra headers to send with request
Returns:	Dict of object metadata.
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

get_object_ring¶

iter_containers(account, marker=”, end_marker=”, acceptable_statuses=(2, 404))¶

Returns an iterator of containers dicts from an account.

Parameters:	account – Account on which to do the container listing. marker – Prefix of first desired item, defaults to ”. end_marker – Last item returned will be ‘less’ than this, defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2, HTTP_NOT_FOUND).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

iter_object_lines(account, container, obj, headers=None, acceptable_statuses=(2, ))¶

Returns an iterator of object lines from an uncompressed or compressed text object.

Uncompress object as it is read if the object’s name ends with ‘.gz’.

Parameters:	account – The object’s account. container – The object’s container. obj – The object. acceptable_statuses – List of status for valid responses, defaults to (2,).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

iter_objects(account, container, marker=”, end_marker=”, acceptable_statuses=(2, 404))¶

Returns an iterator of object dicts from a container.

Parameters:	account – The container’s account. container – Container to iterate objects on. marker – Prefix of first desired item, defaults to ”. end_marker – Last item returned will be ‘less’ than this, defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2, HTTP_NOT_FOUND).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

make_path(account, container=None, obj=None)¶

Returns a swift path for a request quoting and utf-8 encoding the path parts as need be.

Parameters:	account – swift account container – container, defaults to None obj – object, defaults to None
Raises:	ValueError – Is raised if obj is specified and container is not.

make_request(method, path, headers, acceptable_statuses, body_file=None)¶

Makes a request to Swift with retries.

Parameters:	method – HTTP method of request. path – Path of request. headers – Headers to be sent with request. acceptable_statuses – List of acceptable statuses for request. body_file – Body file to be passed along with request, defaults to None.
Returns:	Response object on success.
Raises:	UnexpectedResponse – Exception raised when make_request() fails to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

set_account_metadata(account, metadata, metadata_prefix=”, acceptable_statuses=(2, ))¶

Sets account metadata. A call to this will add to the account metadata and not overwrite all of it with values in the metadata dict. To clear an account metadata value, pass an empty string as the value for the key in the metadata dict.

Parameters:	account – Account on which to get the metadata. metadata – Dict of metadata to set. metadata_prefix – Prefix used to set metadata values in headers of requests, used to prefix keys in metadata when setting metadata, defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

set_container_metadata(account, container, metadata, metadata_prefix=”, acceptable_statuses=(2, ))¶

Sets container metadata. A call to this will add to the container metadata and not overwrite all of it with values in the metadata dict. To clear a container metadata value, pass an empty string as the value for the key in the metadata dict.

Parameters:	account – The container’s account. container – Container to set metadata on. metadata – Dict of metadata to set. metadata_prefix – Prefix used to set metadata values in headers of requests, used to prefix keys in metadata when setting metadata, defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

set_object_metadata(account, container, obj, metadata, metadata_prefix=”, acceptable_statuses=(2, ))¶

Sets an object’s metadata. The object’s metadata will be overwritten by the values in the metadata dict.

Parameters:	account – The object’s account. container – The object’s container. obj – The object. metadata – Dict of metadata to set. metadata_prefix – Prefix used to set metadata values in headers of requests, used to prefix keys in metadata when setting metadata, defaults to ”. acceptable_statuses – List of status for valid responses, defaults to (2,).
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

upload_object(fobj, account, container, obj, headers=None)¶

Parameters:	fobj – File object to read object’s content from. account – The object’s account. container – The object’s container. obj – The object. headers – Headers to send with request, defaults ot empty dict.
Raises:	UnexpectedResponse – Exception raised when requests fail to get a response with an acceptable status Exception – Exception is raised when code fails in an unexpected way.

class swift.common.internal_client.SimpleClient(url=None, token=None, starting_backoff=1, max_backoff=5, retries=5)¶

Bases: object

Simple client that is used in bin/swift-dispersion-* and container sync

base_request(method, container=None, name=None, prefix=None, headers=None, proxy=None, contents=None, full_listing=None, logger=None, additional_info=None, timeout=None, marker=None)¶

get_account(*args, **kwargs)¶

get_container(container, **kwargs)¶

put_container(container, **kwargs)¶

put_object(container, name, contents, **kwargs)¶

retry_request(method, **kwargs)¶

exception swift.common.internal_client.UnexpectedResponse(message, resp)¶

Bases: exceptions.Exception

Exception raised on invalid responses to InternalClient.make_request().

Parameters:	message – Exception message. resp – The unexpected response.

swift.common.internal_client.delete_object(url, **kwargs)¶: For usage with container sync

swift.common.internal_client.get_auth(url, user, key, auth_version=‘1.0’, **kwargs)¶

swift.common.internal_client.head_object(url, **kwargs)¶: For usage with container sync

swift.common.internal_client.put_object(url, **kwargs)¶: For usage with container sync

Manager¶

class swift.common.manager.Manager(servers, run_dir=’/var/run/swift’)¶

Bases: object

Main class for performing commands on groups of servers.

Parameters:	servers – list of server names as strings

force_reload(*a, **kw)¶: alias for reload

get_command(cmd)¶

Find and return the decorated method named like cmd

Parameters:	cmd – the command to get, a string, if not found raises UnknownCommandError

kill(*a, **kw)¶: stop a server (no error if not running)

classmethod list_commands()¶

Get all publicly accessible commands

Returns:	a list of string tuples (cmd, help), the method names who are decorated as commands

no_daemon(*a, **kw)¶: start a server interactively

no_wait(*a, **kw)¶: spawn server and return immediately

once(*a, **kw)¶: start server and run one pass on supporting daemons

reload(*a, **kw)¶: graceful shutdown then restart on supporting servers

restart(*a, **kw)¶: stops then restarts server

run_command(cmd, **kwargs)¶

Find the named command and run it

Parameters:	cmd – the command name to run

shutdown(*a, **kw)¶: allow current requests to finish on supporting servers

start(*a, **kw)¶: starts a server

status(*a, **kw)¶: display status of tracked pids for server

stop(*a, **kw)¶: stops a server

class swift.common.manager.Server(server, run_dir=’/var/run/swift’)¶

Bases: object

Manage operations on a server or group of servers of similar type

Parameters:	server – name of server

conf_files(**kwargs)¶

Get conf files for this server

Param:	number, if supplied will only lookup the nth server
Returns:	list of conf files

get_conf_file_name(pid_file)¶

Translate pid_file to a corresponding conf_file

Parameters:	pid_file – a pid_file for this server, a string
Returns:	the conf_file for this pid_file

get_pid_file_name(conf_file)¶

Translate conf_file to a corresponding pid_file

Parameters:	conf_file – an conf_file for this server, a string
Returns:	the pid_file for this conf_file

get_running_pids(**kwargs)¶

Get running pids

Returns:	a dict mapping pids (ints) to pid_files (paths)

interact(**kwargs)¶: wait on spawned procs to terminate

iter_pid_files(**kwargs)¶: Generator, yields (pid_file, pids)

kill_running_pids(**kwargs)¶

Kill running pids

Parameters:	graceful – if True, attempt SIGHUP on supporting servers
Returns:	a dict mapping pids (ints) to pid_files (paths)

launch(**kwargs)¶: Collect conf files and attempt to spawn the processes for this server

pid_files(**kwargs)¶

Get pid files for this server

Param:	number, if supplied will only lookup the nth server
Returns:	list of pid files

signal_pids(sig, **kwargs)¶

Send a signal to pids for this server

Parameters:	sig – signal to send
Returns:	a dict mapping pids (ints) to pid_files (paths)

spawn(conf_file, once=False, wait=True, daemon=True, **kwargs)¶

Launch a subprocess for this server.

Parameters:	conf_file – path to conf_file to use as first arg once – boolean, add once argument to command wait – boolean, if true capture stdout with a pipe daemon – boolean, if false ask server to log to console
Returns:	the pid of the spawned process

status(pids=None, **kwargs)¶

Display status of server

Param:	pids, if not supplied pids will be populated automatically
Param:	number, if supplied will only lookup the nth server
Returns:	1 if server is not running, 0 otherwise

stop(**kwargs)¶

Send stop signals to pids for this server

Returns:	a dict mapping pids (ints) to pid_files (paths)

wait(**kwargs)¶: wait on spawned procs to start

swift.common.manager.command(func)¶

Decorator to declare which methods are accessible as commands, commands always return 1 or 0, where 0 should indicate success.

Parameters:	func – function to make public

swift.common.manager.kill_group(pid, sig)¶

Send signal to process group

: param pid: process id : param sig: signal to send

swift.common.manager.safe_kill(pid, sig, name)¶

Send signal to process and check process name

: param pid: process id : param sig: signal to send : param name: name to ensure target process

swift.common.manager.setup_env()¶: Try to increase resource limits of the OS. Move PYTHON_EGG_CACHE to /tmp

swift.common.manager.watch_server_pids(server_pids, interval=1, **kwargs)¶

Monitor a collection of server pids yielding back those pids that aren’t responding to signals.

Parameters:	server_pids – a dict, lists of pids [int,…] keyed on Server objects

MemCacheD¶

Why our own memcache client? By Michael Barton

python-memcached doesn’t use consistent hashing, so adding or removing a memcache server from the pool invalidates a huge percentage of cached items.

If you keep a pool of python-memcached client objects, each client object has its own connection to every memcached server, only one of which is ever in use. So you wind up with n * m open sockets and almost all of them idle. This client effectively has a pool for each server, so the number of backend connections is hopefully greatly reduced.

python-memcache uses pickle to store things, and there was already a huge stink about Swift using pickles in memcache (http://osvdb.org/show/osvdb/86581). That seemed sort of unfair, since nova and keystone and everyone else use pickles for memcache too, but it’s hidden behind a “standard” library. But changing would be a security regression at this point.

Also, pylibmc wouldn’t work for us because it needs to use python sockets in order to play nice with eventlet.

Lucid comes with memcached: v1.4.2. Protocol documentation for that version is at:

http://github.com/memcached/memcached/blob/1.4.2/doc/protocol.txt

class swift.common.memcached.MemcacheConnPool(server, size, connect_timeout)¶

Bases: eventlet.pools.Pool

Connection pool for Memcache Connections

The server parameter can be a hostname, an IPv4 address, or an IPv6 address with an optional port. See swift.common.utils.parse_socket_string() for details.

class swift.common.memcached.MemcacheRing(servers, connect_timeout=0.3, io_timeout=2.0, pool_timeout=1.0, tries=3, allow_pickle=False, allow_unpickle=False, max_conns=2)¶

Bases: object

Simple, consistent-hashed memcache client.

decr(key, delta=1, time=0)¶

Decrements a key which has a numeric value by delta. Calls incr with -delta.

Parameters:	key – key delta – amount to subtract to the value of key (or set the value to 0 if the key is not found) will be cast to an int time – the time to live
Returns:	result of decrementing
Raises:	MemcacheConnectionError –

delete(key)¶

Deletes a key/value pair from memcache.

Parameters:	key – key to be deleted

get(key)¶

Gets the object specified by key. It will also unserialize the object before returning if it is serialized in memcache with JSON, or if it is pickled and unpickling is allowed.

Parameters:	key – key
Returns:	value of the key in memcache

get_multi(keys, server_key)¶

Gets multiple values from memcache for the given keys.

Parameters:	keys – keys for values to be retrieved from memcache server_key – key to use in determining which server in the ring is used
Returns:	list of values

incr(key, delta=1, time=0)¶

Increments a key which has a numeric value by delta. If the key can’t be found, it’s added as delta or 0 if delta < 0. If passed a negative number, will use memcached’s decr. Returns the int stored in memcached Note: The data memcached stores as the result of incr/decr is an unsigned int. decr’s that result in a number below 0 are stored as 0.

Parameters:	key – key delta – amount to add to the value of key (or set as the value if the key is not found) will be cast to an int time – the time to live
Returns:	result of incrementing
Raises:	MemcacheConnectionError –

set(key, value, serialize=True, time=0, min_compress_len=0)¶

Set a key/value pair in memcache

Parameters:

key – key
value – value
serialize – if True, value is serialized with JSON before sending to memcache, or with pickle if configured to use pickle instead of JSON (to avoid cache poisoning)
time – the time to live
min_compress_len – minimum compress length, this parameter was added to keep the signature compatible with python-memcached interface. This implementation ignores it.

set_multi(mapping, server_key, serialize=True, time=0, min_compress_len=0)¶

Sets multiple key/value pairs in memcache.

Min_compress_len:
Parameters:	mapping – dictionary of keys and values to be set in memcache server_key – key to use in determining which server in the ring is used serialize – if True, value is serialized with JSON before sending to memcache, or with pickle if configured to use pickle instead of JSON (to avoid cache poisoning) time – the time to live
	minimum compress length, this parameter was added to keep the signature compatible with python-memcached interface. This implementation ignores it

swift.common.memcached.sanitize_timeout(timeout)¶: Sanitize a timeout value to use an absolute expiration time if the delta is greater than 30 days (in seconds). Note that the memcached server translates negative values to mean a delta of 30 days in seconds (and 1 additional second), client beware.

Request Helpers¶

Miscellaneous utility functions for use in generating responses.

Why not swift.common.utils, you ask? Because this way we can import things from swob in here without creating circular imports.

class swift.common.request_helpers.SegmentedIterable(req, app, listing_iter, max_get_time, logger, ua_suffix, swift_source, name=’<not specified>’, response_body_length=None)¶

Bases: object

Iterable that returns the object contents for a large object.

Parameters:

req – original request object
app – WSGI application from which segments will come
listing_iter –
iterable yielding the object segments to fetch, along with the byte subranges to fetch, in the form of a 5-tuple (object-path, object-etag, object-size, first-byte, last-byte).

If object-etag is None, no MD5 verification will be done.

If object-size is None, no length verification will be done.

If first-byte and last-byte are None, then the entire object will be fetched.
max_get_time – maximum permitted duration of a GET request (seconds)
logger – logger object
swift_source – value of swift.source in subrequest environ (just for logging)
ua_suffix – string to append to user-agent.
name – name of manifest (used in logging only)
response_body_length – optional response body length for the response being sent to the client.

app_iter_range(*a, **kw)¶

swob.Response will only respond with a 206 status in certain cases; one of those is if the body iterator responds to .app_iter_range().

However, this object (or really, its listing iter) is smart enough to handle the range stuff internally, so we just no-op this out for swob.

app_iter_ranges(ranges, content_type, boundary, content_size)¶

This method assumes that iter(self) yields all the data bytes that go into the response, but none of the MIME stuff. For example, if the response will contain three MIME docs with data “abcd”, “efgh”, and “ijkl”, then iter(self) will give out the bytes “abcdefghijkl”.

This method inserts the MIME stuff around the data bytes.

close()¶: Called when the client disconnect. Ensure that the connection to the backend server is closed.

validate_first_segment()¶

Start fetching object data to ensure that the first segment (if any) is valid. This is to catch cases like “first segment is missing” or “first segment’s etag doesn’t match manifest”.

Note: this does not validate that you have any segments. A zero-segment large object is not erroneous; it is just empty.

swift.common.request_helpers.copy_header_subset(from_r, to_r, condition)¶

Will copy desired subset of headers from from_r to to_r.

Parameters:	from_r – a swob Request or Response to_r – a swob Request or Response condition – a function that will be passed the header key as a single argument and should return True if the header is to be copied.

swift.common.request_helpers.get_listing_content_type(req)¶

Determine the content type to use for an account or container listing response.

Parameters:	req – request object
Returns:	content type as a string (e.g. text/plain, application/json)
Raises:	HTTPNotAcceptable – if the requested content type is not acceptable HTTPBadRequest – if the ‘format’ query param is provided and not valid UTF-8

swift.common.request_helpers.get_name_and_placement(request, minsegs=1, maxsegs=None, rest_with_last=False)¶

Utility function to split and validate the request path and storage policy. The storage policy index is extracted from the headers of the request and converted to a StoragePolicy instance. The remaining args are passed through to split_and_validate_path().

Returns:	a list, result of `split_and_validate_path()` with the BaseStoragePolicy instance appended on the end
Raises:	HTTPServiceUnavailable – if the path is invalid or no policy exists with the extracted policy_index.

swift.common.request_helpers.get_object_transient_sysmeta(key)¶

Returns the Object Transient System Metadata header for key. The Object Transient System Metadata namespace will be persisted by backend object servers. These headers are treated in the same way as object user metadata i.e. all headers in this namespace will be replaced on every POST request.

Parameters:	key – metadata key
Returns:	the entire object transient system metadata header for key

swift.common.request_helpers.get_param(req, name, default=None)¶

Get parameters from an HTTP request ensuring proper handling UTF-8 encoding.

Parameters:	req – request object name – parameter name default – result to return if the parameter is not found
Returns:	HTTP request parameter value (as UTF-8 encoded str, not unicode object)
Raises:	HTTPBadRequest – if param not valid UTF-8 byte sequence

swift.common.request_helpers.get_sys_meta_prefix(server_type)¶

Returns the prefix for system metadata headers for given server type.

This prefix defines the namespace for headers that will be persisted by backend servers.

Parameters:	server_type – type of backend server i.e. [account\|container\|object]
Returns:	prefix string for server type’s system metadata headers

swift.common.request_helpers.get_user_meta_prefix(server_type)¶

Returns the prefix for user metadata headers for given server type.

This prefix defines the namespace for headers that will be persisted by backend servers.

Parameters:	server_type – type of backend server i.e. [account\|container\|object]
Returns:	prefix string for server type’s user metadata headers

swift.common.request_helpers.http_response_to_document_iters(response, read_chunk_size=4096)¶

Takes a successful object-GET HTTP response and turns it into an iterator of (first-byte, last-byte, length, headers, body-file) 5-tuples.

The response must either be a 200 or a 206; if you feed in a 204 or something similar, this probably won’t work.

Parameters:	response – HTTP response, like from bufferedhttp.http_connect(), not a swob.Response.

swift.common.request_helpers.is_object_transient_sysmeta(key)¶

Tests if a header key starts with and is longer than the prefix for object transient system metadata.

Parameters:	key – header key
Returns:	True if the key satisfies the test, False otherwise

swift.common.request_helpers.is_sys_meta(server_type, key)¶

Tests if a header key starts with and is longer than the system metadata prefix for given server type.

Parameters:	server_type – type of backend server i.e. [account\|container\|object] key – header key
Returns:	True if the key satisfies the test, False otherwise

swift.common.request_helpers.is_sys_or_user_meta(server_type, key)¶

Tests if a header key starts with and is longer than the user or system metadata prefix for given server type.

Parameters:	server_type – type of backend server i.e. [account\|container\|object] key – header key
Returns:	True if the key satisfies the test, False otherwise

swift.common.request_helpers.is_user_meta(server_type, key)¶

Tests if a header key starts with and is longer than the user metadata prefix for given server type.

Parameters:	server_type – type of backend server i.e. [account\|container\|object] key – header key
Returns:	True if the key satisfies the test, False otherwise

swift.common.request_helpers.remove_items(headers, condition)¶

Removes items from a dict whose keys satisfy the given condition.

Parameters:	headers – a dict of headers condition – a function that will be passed the header key as a single argument and should return True if the header is to be removed.
Returns:	a dict, possibly empty, of headers that have been removed

swift.common.request_helpers.resolve_etag_is_at_header(req, metadata)¶

Helper function to resolve an alternative etag value that may be stored in metadata under an alternate name.

The value of the request’s X-Backend-Etag-Is-At header (if it exists) is a comma separated list of alternate names in the metadata at which an alternate etag value may be found. This list is processed in order until an alternate etag is found.

The left most value in X-Backend-Etag-Is-At will have been set by the left most middleware, or if no middleware, by ECObjectController, if an EC policy is in use. The left most middleware is assumed to be the authority on what the etag value of the object content is.

The resolver will work from left to right in the list until it finds a value that is a name in the given metadata. So the left most wins, IF it exists in the metadata.

By way of example, assume the encrypter middleware is installed. If an object is not encrypted then the resolver will not find the encrypter middleware’s alternate etag sysmeta (X-Object-Sysmeta-Crypto-Etag) but will then find the EC alternate etag (if EC policy). But if the object is encrypted then X-Object-Sysmeta-Crypto-Etag is found and used, which is correct because it should be preferred over X-Object-Sysmeta-Crypto-Etag.

Parameters:	req – a swob Request metadata – a dict containing object metadata
Returns:	an alternate etag value if any is found, otherwise None

swift.common.request_helpers.split_and_validate_path(request, minsegs=1, maxsegs=None, rest_with_last=False)¶

Utility function to split and validate the request path.

Returns:	result of `split_path()` if everything’s okay
Raises:	HTTPBadRequest – if something’s not okay

swift.common.request_helpers.strip_object_transient_sysmeta_prefix(key)¶

Removes the object transient system metadata prefix from the start of a header key.

Parameters:	key – header key
Returns:	stripped header key

swift.common.request_helpers.strip_sys_meta_prefix(server_type, key)¶

Removes the system metadata prefix for a given server type from the start of a header key.

Parameters:	server_type – type of backend server i.e. [account\|container\|object] key – header key
Returns:	stripped header key

swift.common.request_helpers.strip_user_meta_prefix(server_type, key)¶

Removes the user metadata prefix for a given server type from the start of a header key.

Parameters:	server_type – type of backend server i.e. [account\|container\|object] key – header key
Returns:	stripped header key

swift.common.request_helpers.update_etag_is_at_header(req, name)¶

Helper function to update an X-Backend-Etag-Is-At header whose value is a list of alternative header names at which the actual object etag may be found. This informs the object server where to look for the actual object etag when processing conditional requests.

Since the proxy server and/or middleware may set alternative etag header names, the value of X-Backend-Etag-Is-At is a comma separated list which the object server inspects in order until it finds an etag value.

Parameters:	req – a swob Request name – name of a sysmeta where alternative etag may be found

Swob¶

Implementation of WSGI Request and Response objects.

This library has a very similar API to Webob. It wraps WSGI request environments and response values into objects that are more friendly to interact with.

Why Swob and not just use WebOb? By Michael Barton

We used webob for years. The main problem was that the interface wasn’t stable. For a while, each of our several test suites required a slightly different version of webob to run, and none of them worked with the then-current version. It was a huge headache, so we just scrapped it.

This is kind of a ton of code, but it’s also been a huge relief to not have to scramble to add a bunch of code branches all over the place to keep Swift working every time webob decides some interface needs to change.

class swift.common.swob.Accept(headerval)¶

Bases: object

Wraps a Request’s Accept header as a friendly object.

Parameters:	headerval – value of the header as a str

best_match(options)¶

Returns the item from “options” that best matches the accept header. Returns None if no available options are acceptable to the client.

Parameters:	options – a list of content-types the server can respond with

class swift.common.swob.HeaderEnvironProxy(environ)¶

Bases: _abcoll.MutableMapping

A dict-like object that proxies requests to a wsgi environ, rewriting header keys to environ keys.

For example, headers[‘Content-Range’] sets and gets the value of headers.environ[‘HTTP_CONTENT_RANGE’]

class swift.common.swob.Match(headerval)¶

Bases: object

Wraps a Request’s If-[None-]Match header as a friendly object.

Parameters:	headerval – value of the header as a str

class swift.common.swob.Range(headerval)¶

Bases: object

Wraps a Request’s Range header as a friendly object. After initialization, “range.ranges” is populated with a list of (start, end) tuples denoting the requested ranges.

If there were any syntactically-invalid byte-range-spec values, the constructor will raise a ValueError, per the relevant RFC:

“The recipient of a byte-range-set that includes one or more syntactically invalid byte-range-spec values MUST ignore the header field that includes that byte-range-set.”

According to the RFC 2616 specification, the following cases will be all considered as syntactically invalid, thus, a ValueError is thrown so that the range header will be ignored. If the range value contains at least one of the following cases, the entire range is considered invalid, ValueError will be thrown so that the header will be ignored.

value not starts with bytes=
range value start is greater than the end, eg. bytes=5-3
range does not have start or end, eg. bytes=-
range does not have hyphen, eg. bytes=45
range value is non numeric
any combination of the above

Every syntactically valid range will be added into the ranges list even when some of the ranges may not be satisfied by underlying content.

Parameters:	headerval – value of the header as a str

ranges_for_length(length)¶

This method is used to return multiple ranges for a given length which should represent the length of the underlying content. The constructor method __init__ made sure that any range in ranges list is syntactically valid. So if length is None or size of the ranges is zero, then the Range header should be ignored which will eventually make the response to be 200.

If an empty list is returned by this method, it indicates that there are unsatisfiable ranges found in the Range header, 416 will be returned.

if a returned list has at least one element, the list indicates that there is at least one range valid and the server should serve the request with a 206 status code.

The start value of each range represents the starting position in the content, the end value represents the ending position. This method purposely adds 1 to the end number because the spec defines the Range to be inclusive.

The Range spec can be found at the following link: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.1

Parameters:	length – length of the underlying content

class swift.common.swob.Request(environ)¶

Bases: object

WSGI Request object.

accept¶: Retrieve and set the accept property in the WSGI environ, as a Accept object

acl¶: Get and set the swob.ACL property in the WSGI environment

classmethod blank(path, environ=None, headers=None, body=None, **kwargs)¶

Create a new request object with the given parameters, and an environment otherwise filled in with non-surprising default values.

Parameters:	path – encoded, parsed, and unquoted into PATH_INFO environ – WSGI environ dictionary headers – HTTP headers body – stuffed in a WsgiBytesIO and hung on wsgi.input kwargs – any environ key with an property setter

body¶: Get and set the request body str

body_file¶: Get and set the wsgi.input property in the WSGI environment

call_application(application)¶

Calls the application with this request’s environment. Returns the status, headers, and app_iter for the response as a tuple.

Parameters:	application – the WSGI application to call

content_length¶: Retrieve and set the content-length header as an int

copy_get()¶: Makes a copy of the request, converting it to a GET.

get_response(application)¶

Calls the application with this request’s environment. Returns a Response object that wraps up the application’s result.

Parameters:	application – the WSGI application to call

host¶: Get and set the HTTP_HOST property in the WSGI environment

host_url¶: Get url for request/response up to path

if_match¶: Retrieve and set the if-match property in the WSGI environ, as a Match object

if_modified_since¶: Retrieve and set the if-modified-since header as a datetime, set it with a datetime, int, or str

if_none_match¶: Retrieve and set the if-none-match property in the WSGI environ, as a Match object

if_unmodified_since¶: Retrieve and set the if-unmodified-since header as a datetime, set it with a datetime, int, or str

message_length()¶

Properly determine the message length for this request. It will return an integer if the headers explicitly contain the message length, or None if the headers don’t contain a length. The ValueError exception will be raised if the headers are invalid.

Raises:	ValueError – if either transfer-encoding or content-length headers have bad values AttributeError – if the last value of the transfer-encoding header is not “chunked”

method¶: Get and set the REQUEST_METHOD property in the WSGI environment

params¶: Provides QUERY_STRING parameters as a dictionary

path¶: Provides the full path of the request, excluding the QUERY_STRING

path_info¶: Get and set the PATH_INFO property in the WSGI environment

path_info_pop()¶: Takes one path portion (delineated by slashes) from the path_info, and appends it to the script_name. Returns the path segment.

path_qs¶: The path of the request, without host but with query string.

query_string¶: Get and set the QUERY_STRING property in the WSGI environment

range¶: Retrieve and set the range property in the WSGI environ, as a Range object

referer¶: Get and set the HTTP_REFERER property in the WSGI environment

referrer¶: Get and set the HTTP_REFERER property in the WSGI environment

remote_addr¶: Get and set the REMOTE_ADDR property in the WSGI environment

remote_user¶: Get and set the REMOTE_USER property in the WSGI environment

script_name¶: Get and set the SCRIPT_NAME property in the WSGI environment

split_path(minsegs=1, maxsegs=None, rest_with_last=False)¶

Validate and split the Request’s path.

Examples:

['a'] = split_path('/a')
['a', None] = split_path('/a', 1, 2)
['a', 'c'] = split_path('/a/c', 1, 2)
['a', 'c', 'o/r'] = split_path('/a/c/o/r', 1, 3, True)

Parameters:	minsegs – Minimum number of segments to be extracted maxsegs – Maximum number of segments to be extracted rest_with_last – If True, trailing data will be returned as part of last segment. If False, and there is trailing data, raises ValueError.
Returns:	list of segments with a length of maxsegs (non-existent segments will return as None)
Raises:	ValueError – if given an invalid path

str_params¶: Provides QUERY_STRING parameters as a dictionary

swift_entity_path¶

Provides the account/container/object path, sans API version.

This can be useful when constructing a path to send to a backend server, as that path will need everything after the “/v1”.

timestamp¶: Provides HTTP_X_TIMESTAMP as a Timestamp

url¶: Provides the full url of the request

user_agent¶: Get and set the HTTP_USER_AGENT property in the WSGI environment

class swift.common.swob.Response(body=None, status=200, headers=None, app_iter=None, request=None, conditional_response=False, conditional_etag=None, **kw)¶

Bases: object

WSGI Response object.

__call__(env, start_response)¶: Respond to the WSGI request.

Warning

This will translate any relative Location header value to an absolute URL using the WSGI environment’s HOST_URL as a prefix, as RFC 2616 specifies.

However, it is quite common to use relative redirects, especially when it is difficult to know the exact HOST_URL the browser would have used when behind several CNAMEs, CDN services, etc. All modern browsers support relative redirects.

To skip over RFC enforcement of the Location header value, you may set env['swift.leave_relative_location'] = True in the WSGI environment.

absolute_location()¶: Attempt to construct an absolute location.

accept_ranges¶: Retrieve and set the accept-ranges header

app_iter¶: Retrieve and set the response app_iter

body¶: Retrieve and set the Response body str

charset¶: Retrieve and set the response charset

conditional_etag¶

The conditional_etag keyword argument for Response will allow the conditional match value of a If-Match request to be compared to a non-standard value.

This is available for Storage Policies that do not store the client object data verbatim on the storage nodes, but still need support conditional requests.

It’s most effectively used with X-Backend-Etag-Is-At which would define the additional Metadata key(s) where the original ETag of the clear-form client request data may be found.

content_length¶: Retrieve and set the content-length header as an int

content_range¶: Retrieve and set the content-range header

content_type¶: Retrieve and set the response Content-Type header

etag¶: Retrieve and set the response Etag header

fix_conditional_response()¶

You may call this once you have set the content_length to the whole object length and body or app_iter to reset the content_length properties on the request.

It is ok to not call this method, the conditional response will be maintained for you when you __call__ the response.

host_url¶: Get url for request/response up to path

last_modified¶: Retrieve and set the last-modified header as a datetime, set it with a datetime, int, or str

location¶: Retrieve and set the location header

status¶: Retrieve and set the Response status, e.g. ‘200 OK’

www_authenticate()¶

Construct a suitable value for WWW-Authenticate response header

If we have a request and a valid-looking path, the realm is the account; otherwise we set it to ‘unknown’.

class swift.common.swob.StatusMap¶

Bases: object

A dict-like object that returns HTTPException subclasses/factory functions where the given key is the status code.

class swift.common.swob.WsgiBytesIO(buf=”)¶

Bases: StringIO.StringIO

This class adds support for the additional wsgi.input methods defined on eventlet.wsgi.Input to the BytesIO class which would otherwise be a fine stand-in for the file-like object in the WSGI environment.

swift.common.swob.wsgify(func)¶: A decorator for translating functions which take a swob Request object and return a Response object into WSGI callables. Also catches any raised HTTPExceptions and treats them as a returned Response.

Utils¶

Miscellaneous utility functions for use with Swift.

class swift.common.utils.CloseableChain(*iterables)¶

Bases: object

Like itertools.chain, but with a close method that will attempt to invoke its sub-iterators’ close methods, if any.

class swift.common.utils.ContextPool(size=1000)¶

Bases: eventlet.greenpool.GreenPool

GreenPool subclassed to kill its coros when it gets gc’ed

class swift.common.utils.GreenAsyncPile(size_or_pool)¶

Bases: object

Runs jobs in a pool of green threads, and the results can be retrieved by using this object as an iterator.

This is very similar in principle to eventlet.GreenPile, except it returns results as they become available rather than in the order they were launched.

Correlating results with jobs (if necessary) is left to the caller.

spawn(func, *args, **kwargs)¶: Spawn a job in a green thread on the pile.

waitall(timeout)¶

Wait timeout seconds for any results to come in.

Parameters:	timeout – seconds to wait for results
Returns:	list of results accrued in that time

waitfirst(timeout)¶

Wait up to timeout seconds for first result to come in.

Parameters:	timeout – seconds to wait for results
Returns:	first item to come back, or None

class swift.common.utils.GreenthreadSafeIterator(unsafe_iterable)¶

Bases: object

Wrap an iterator to ensure that only one greenthread is inside its next() method at a time.

This is useful if an iterator’s next() method may perform network IO, as that may trigger a greenthread context switch (aka trampoline), which can give another greenthread a chance to call next(). At that point, you get an error like “ValueError: generator already executing”. By wrapping calls to next() with a mutex, we avoid that error.

class swift.common.utils.InputProxy(wsgi_input)¶

Bases: object

File-like object that counts bytes read. To be swapped in for wsgi.input for accounting purposes.

read(*args, **kwargs)¶: Pass read request to the underlying file-like object and add bytes read to total.

readline(*args, **kwargs)¶: Pass readline request to the underlying file-like object and add bytes read to total.

class swift.common.utils.LRUCache(maxsize=1000, maxtime=3600)¶

Bases: object

Decorator for size/time bound memoization that evicts the least recently used members.

class swift.common.utils.LogAdapter(logger, server)¶

Bases: logging.LoggerAdapter, object

A Logger like object which performs some reformatting on calls to exception(). Can be used to store a threadlocal transaction id and client ip.

notice(msg, *args, **kwargs)¶: Convenience function for syslog priority LOG_NOTICE. The python logging lvl is set to 25, just above info. SysLogHandler is monkey patched to map this log lvl to the LOG_NOTICE syslog priority.

process(msg, kwargs)¶: Add extra info to message

set_statsd_prefix(prefix)¶: The StatsD client prefix defaults to the “name” of the logger. This method may override that default with a specific value. Currently used in the proxy-server to differentiate the Account, Container, and Object controllers.

statsd_delegate(statsd_func_name)¶

Factory to create methods which delegate to methods on self.logger.statsd_client (an instance of StatsdClient). The created methods conditionally delegate to a method whose name is given in ‘statsd_func_name’. The created delegate methods are a no-op when StatsD logging is not configured.

Parameters:	statsd_func_name – the name of a method on StatsdClient.

class swift.common.utils.ModifiedParseResult¶

Bases: urlparse.ParseResult

Parse results class for urlparse.

swift.common.utils.NR_ioprio_set()¶: Give __NR_ioprio_set value for your system.

class swift.common.utils.NullLogger¶

Bases: object

A no-op logger for eventlet wsgi.

class swift.common.utils.RateLimitedIterator(iterable, elements_per_second, limit_after=0, ratelimit_if=<function <lambda>>)¶

Bases: object

Wrap an iterator to only yield elements at a rate of N per second.

Parameters:	iterable – iterable to wrap elements_per_second – the rate at which to yield elements limit_after – rate limiting kicks in only after yielding this many elements; default is 0 (rate limit immediately)

class swift.common.utils.Spliterator(source_iterable)¶

Bases: object

Takes an iterator yielding sliceable things (e.g. strings or lists) and yields subiterators, each yielding up to the requested number of items from the source.

>>> si = Spliterator(["abcde", "fg", "hijkl"])
>>> ''.join(si.take(4))
"abcd"
>>> ''.join(si.take(3))
"efg"
>>> ''.join(si.take(1))
"h"
>>> ''.join(si.take(3))
"ijk"
>>> ''.join(si.take(3))
"l"  # shorter than requested; this can happen with the last iterator

class swift.common.utils.StreamingPile(size)¶

Bases: swift.common.utils.GreenAsyncPile

Runs jobs in a pool of green threads, spawning more jobs as results are retrieved and worker threads become available.

When used as a context manager, has the same worker-killing properties as ContextPool.

asyncstarmap(func, args_iter)¶: This is the same as itertools.starmap(), except that func is executed in a separate green thread for each item, and results won’t necessarily have the same order as inputs.

class swift.common.utils.SwiftLogFormatter(fmt=None, datefmt=None, max_line_length=0)¶

Bases: logging.Formatter

Custom logging.Formatter will append txn_id to a log message if the record has one and the message does not. Optionally it can shorten overly long log lines.

class swift.common.utils.Timestamp(timestamp, offset=0, delta=0)¶

Bases: object

Internal Representation of Swift Time.

The normalized form of the X-Timestamp header looks like a float with a fixed width to ensure stable string sorting - normalized timestamps look like “1402464677.04188”

To support overwrites of existing data without modifying the original timestamp but still maintain consistency a second internal offset vector is append to the normalized timestamp form which compares and sorts greater than the fixed width float format but less than a newer timestamp. The internalized format of timestamps looks like “1402464677.04188_0000000000000000” - the portion after the underscore is the offset and is a formatted hexadecimal integer.

The internalized form is not exposed to clients in responses from Swift. Normal client operations will not create a timestamp with an offset.

The Timestamp class in common.utils supports internalized and normalized formatting of timestamps and also comparison of timestamp values. When the offset value of a Timestamp is 0 - it’s considered insignificant and need not be represented in the string format; to support backwards compatibility during a Swift upgrade the internalized and normalized form of a Timestamp with an insignificant offset are identical. When a timestamp includes an offset it will always be represented in the internalized form, but is still excluded from the normalized form. Timestamps with an equivalent timestamp portion (the float part) will compare and order by their offset. Timestamps with a greater timestamp portion will always compare and order greater than a Timestamp with a lesser timestamp regardless of it’s offset. String comparison and ordering is guaranteed for the internalized string format, and is backwards compatible for normalized timestamps which do not include an offset.

swift.common.utils.affinity_key_function(affinity_str)¶

Turns an affinity config value into a function suitable for passing to sort(). After doing so, the array will be sorted with respect to the given ordering.

For example, if affinity_str is “r1=1, r2z7=2, r2z8=2”, then the array will be sorted with all nodes from region 1 (r1=1) first, then all the nodes from region 2 zones 7 and 8 (r2z7=2 and r2z8=2), then everything else.

Note that the order of the pieces of affinity_str is irrelevant; the priority values are what comes after the equals sign.

If affinity_str is empty or all whitespace, then the resulting function will not alter the ordering of the nodes.

Parameters:	affinity_str – affinity config value, e.g. “r1z2=3” or “r1=1, r2z1=2, r2z2=2”
Returns:	single-argument function
Raises:	ValueError – if argument invalid

swift.common.utils.affinity_locality_predicate(write_affinity_str)¶

Turns a write-affinity config value into a predicate function for nodes. The returned value will be a 1-arg function that takes a node dictionary and returns a true value if it is “local” and a false value otherwise. The definition of “local” comes from the affinity_str argument passed in here.

For example, if affinity_str is “r1, r2z2”, then only nodes where region=1 or where (region=2 and zone=2) are considered local.

If affinity_str is empty or all whitespace, then the resulting function will consider everything local

Parameters:	write_affinity_str – affinity config value, e.g. “r1z2” or “r1, r2z1, r2z2”
Returns:	single-argument function, or None if affinity_str is empty
Raises:	ValueError – if argument invalid

swift.common.utils.audit_location_generator(devices, datadir, suffix=”, mount_check=True, logger=None)¶

Given a devices path and a data directory, yield (path, device, partition) for all files in that directory

Parameters:	devices – parent directory of the devices to be audited datadir – a directory located under self.devices. This should be one of the DATADIR constants defined in the account, container, and object servers. suffix – path name suffix required for all names returned mount_check – Flag to check if a mount check should be performed on devices logger – a logger object

swift.common.utils.backward(f, blocksize=4096)¶

A generator returning lines from a file starting with the last line, then the second last line, etc. i.e., it reads lines backwards. Stops when the first line (if any) is read. This is useful when searching for recent activity in very large files.

Parameters:	f – file object to read blocksize – no of characters to go backwards at each block

swift.common.utils.cache_from_env(env, allow_none=False)¶

Get memcache connection pool from the environment (which had been previously set by the memcache middleware

Parameters:	env – wsgi environment dict
Returns:	swift.common.memcached.MemcacheRing from environment

swift.common.utils.capture_stdio(logger, **kwargs)¶

Log unhandled exceptions, close stdio, capture stdout and stderr.

param logger: Logger object to use

swift.common.utils.closing_if_possible(*args, **kwds)¶

Like contextlib.closing(), but doesn’t crash if the object lacks a close() method.

PEP 333 (WSGI) says: “If the iterable returned by the application has a close() method, the server or gateway must call that method upon completion of the current request[.]” This function makes that easier.

swift.common.utils.compute_eta(start_time, current_value, final_value)¶

Compute an ETA. Now only if we could also have a progress bar…

Parameters:	start_time – Unix timestamp when the operation began current_value – Current value final_value – Final value
Returns:	ETA as a tuple of (length of time, unit of time) where unit of time is one of (‘h’, ‘m’, ‘s’)

swift.common.utils.config_auto_int_value(value, default)¶: Returns default if value is None or ‘auto’. Returns value as an int or raises ValueError otherwise.

swift.common.utils.config_fallocate_value(reserve_value)¶: Returns fallocate reserve_value as an int or float. Returns is_percent as a boolean. Returns a ValueError on invalid fallocate value.

swift.common.utils.config_positive_int_value(value)¶: Returns positive int value if it can be cast by int() and it’s an integer > 0. (not including zero) Raises ValueError otherwise.

swift.common.utils.config_read_prefixed_options(conf, prefix_name, defaults)¶

Read prefixed options from configuration

Parameters:	conf – the configuration prefix_name – the prefix (including, if needed, an underscore) defaults – a dict of default values. The dict supplies the option name and type (string or comma separated string)
Returns:	a dict containing the options

swift.common.utils.config_read_reseller_options(conf, defaults)¶

Read reseller_prefix option and associated options from configuration

Reads the reseller_prefix option, then reads options that may be associated with a specific reseller prefix. Reads options such that an option without a prefix applies to all reseller prefixes unless an option has an explicit prefix.

Parameters:	conf – the configuration defaults – a dict of default values. The key is the option name. The value is either an array of strings or a string
Returns:	tuple of an array of reseller prefixes and a dict of option values

swift.common.utils.config_true_value(value)¶: Returns True if the value is either True or a string in TRUE_VALUES. Returns False otherwise.

swift.common.utils.csv_append(csv_string, item)¶

Appends an item to a comma-separated string.

If the comma-separated string is empty/None, just returns item.

swift.common.utils.decode_timestamps(encoded, explicit=False)¶: Parses a string of the form generated by encode_timestamps and returns a tuple of the three component timestamps. If explicit is False, component timestamps that are not explicitly encoded will be assumed to have zero delta from the previous component and therefore take the value of the previous component. If explicit is True, component timestamps that are not explicitly encoded will be returned with value None.

swift.common.utils.document_iters_to_http_response_body(ranges_iter, boundary, multipart, logger)¶

Takes an iterator of range iters and turns it into an appropriate HTTP response body, whether that’s multipart/byteranges or not.

This is almost, but not quite, the inverse of request_helpers.http_response_to_document_iters(). This function only yields chunks of the body, not any headers.

Parameters:

ranges_iter –
an iterator of dictionaries, one per range. Each dictionary must contain at least the following key: “part_iter”: iterator yielding the bytes in the range

Additionally, if multipart is True, then the following other keys are required:

”start_byte”: index of the first byte in the range “end_byte”: index of the last byte in the range “content_type”: value for the range’s Content-Type header

Finally, there is one optional key that is used in the

multipart/byteranges case:

”entity_length”: length of the requested entity (not necessarily

equal to the response length). If omitted, “*” will be used.

Each part_iter will be exhausted prior to calling next(ranges_iter).
boundary – MIME boundary to use, sans dashes (e.g. “boundary”, not “–boundary”).
multipart – True if the response should be multipart/byteranges, False otherwise. This should be True if and only if you have 2 or more ranges.
logger – a logger

swift.common.utils.document_iters_to_multipart_byteranges(ranges_iter, boundary)¶

Takes an iterator of range iters and yields a multipart/byteranges MIME document suitable for sending as the body of a multi-range 206 response.

See document_iters_to_http_response_body for parameter descriptions.

swift.common.utils.drop_buffer_cache(fd, offset, length)¶

Drop ‘buffer’ cache for the given range of the given file.

Parameters:	fd – file descriptor offset – start offset length – length

swift.common.utils.drop_privileges(user, call_setsid=True)¶

Sets the userid/groupid of the current process, get session leader, etc.

Parameters:	user – User name to change privileges to

swift.common.utils.dump_recon_cache(cache_dict, cache_file, logger, lock_timeout=2, set_owner=None)¶

Update recon cache values

Parameters:	cache_dict – Dictionary of cache key/value pairs to write out cache_file – cache file to update logger – the logger to use to log an encountered error lock_timeout – timeout (in seconds) set_owner – Set owner of recon cache file

swift.common.utils.encode_timestamps(t1, t2=None, t3=None, explicit=False)¶

Encode up to three timestamps into a string. Unlike a Timestamp object, the encoded string does NOT used fixed width fields and consequently no relative chronology of the timestamps can be inferred from lexicographic sorting of encoded timestamp strings.

The format of the encoded string is:: <t1>[<+/-><t2 - t1>[<+/-><t3 - t2>]]

i.e. if t1 = t2 = t3 then just the string representation of t1 is returned, otherwise the time offsets for t2 and t3 are appended. If explicit is True then the offsets for t2 and t3 are always appended even if zero.

Note: any offset value in t1 will be preserved, but offsets on t2 and t3 are not preserved. In the anticipated use cases for this method (and the inverse decode_timestamps method) the timestamps passed as t2 and t3 are not expected to have offsets as they will be timestamps associated with a POST request. In the case where the encoding is used in a container objects table row, t1 could be the PUT or DELETE time but t2 and t3 represent the content type and metadata times (if different from the data file) i.e. correspond to POST timestamps. In the case where the encoded form is used in a .meta file name, t1 and t2 both correspond to POST timestamps.

swift.common.utils.expand_ipv6(address)¶: Expand ipv6 address. :param address: a string indicating valid ipv6 address :returns: a string indicating fully expanded ipv6 address

swift.common.utils.extract_swift_bytes(content_type)¶

Parse a content-type and return a tuple containing:

the content_type string minus any swift_bytes param,
the swift_bytes value or None if the param was not found

Parameters:	content_type – a content-type string
Returns:	a tuple of (content-type, swift_bytes or None)

swift.common.utils.fallocate(fd, size)¶

Pre-allocate disk space for a file.

Parameters:	fd – file descriptor size – size to allocate (in bytes)

swift.common.utils.fdatasync(fd)¶

Sync modified file data to disk.

Parameters:	fd – file descriptor

swift.common.utils.fsync(fd)¶

Sync modified file data and metadata to disk.

Parameters:	fd – file descriptor

swift.common.utils.fsync_dir(dirpath)¶

Sync directory entries to disk.

Parameters:	dirpath – Path to the directory to be synced.

swift.common.utils.get_expirer_container(x_delete_at, expirer_divisor, acc, cont, obj)¶: Returns a expiring object container name for given X-Delete-At and a/c/o.

swift.common.utils.get_hmac(request_method, path, expires, key)¶

Returns the hexdigest string of the HMAC-SHA1 (RFC 2104) for the request.

Parameters:	request_method – Request method to allow. path – The path to the resource to allow access to. expires – Unix timestamp as an int for when the URL expires. key – HMAC shared secret.
Returns:	hexdigest str of the HMAC-SHA1 for the request.

swift.common.utils.get_hub()¶

Checks whether poll is available and falls back on select if it isn’t.

Note about epoll:

Review: https://review.openstack.org/#/c/18806/

There was a problem where once out of every 30 quadrillion connections, a coroutine wouldn’t wake up when the client closed its end. Epoll was not reporting the event or it was getting swallowed somewhere. Then when that file descriptor was re-used, eventlet would freak right out because it still thought it was waiting for activity from it in some other coro.

swift.common.utils.get_log_line(req, res, trans_time, additional_info)¶

Make a line for logging that matches the documented log line format for backend servers.

Parameters:	req – the request. res – the response. trans_time – the time the request took to complete, a float. additional_info – a string to log at the end of the line
Returns:	a properly formatted line for logging.

swift.common.utils.get_logger(conf, name=None, log_to_console=False, log_route=None, fmt=’%(server)s: %(message)s’)¶

Get the current system logger using config settings.

Log config and defaults:

log_facility = LOG_LOCAL0
log_level = INFO
log_name = swift
log_max_line_length = 0
log_udp_host = (disabled)
log_udp_port = logging.handlers.SYSLOG_UDP_PORT
log_address = /dev/log
log_statsd_host = (disabled)
log_statsd_port = 8125
log_statsd_default_sample_rate = 1.0
log_statsd_sample_rate_factor = 1.0
log_statsd_metric_prefix = (empty-string)

Parameters:	conf – Configuration dict to read settings from name – Name of the logger log_to_console – Add handler which writes to console on stderr log_route – Route for the logging, not emitted to the log, just used to separate logging configurations fmt – Override log format

swift.common.utils.get_md5_socket()¶

Get an MD5 socket file descriptor. One can MD5 data with it by writing it to the socket with os.write, then os.read the 16 bytes of the checksum out later.

NOTE: It is the caller’s responsibility to ensure that os.close() is called on the returned file descriptor. This is a bare file descriptor, not a Python object. It doesn’t close itself.

swift.common.utils.get_policy_index(req_headers, res_headers)¶

Returns the appropriate index of the storage policy for the request from a proxy server

Parameters:	req_headers – dict of the request headers. res_headers – dict of the response headers.
Returns:	string index of storage policy, or None

swift.common.utils.get_swift_info(admin=False, disallowed_sections=None)¶

Returns information about the swift cluster that has been previously registered with the register_swift_info call.

Parameters:	admin – boolean value, if True will additionally return an ‘admin’ section with information previously registered as admin info. disallowed_sections – list of section names to be withheld from the information returned.
Returns:	dictionary of information about the swift cluster.

swift.common.utils.get_time_units(time_amount)¶

Get a nomralized length of time in the largest unit of time (hours, minutes, or seconds.)

Parameters:	time_amount – length of time in seconds
Returns:	A touple of (length of time, unit of time) where unit of time is one of (‘h’, ‘m’, ‘s’)

swift.common.utils.get_valid_utf8_str(str_or_unicode)¶

Get valid parts of utf-8 str from str, unicode and even invalid utf-8 str

Parameters:	str_or_unicode – a string or an unicode which can be invalid utf-8

swift.common.utils.hash_path(account, container=None, object=None, raw_digest=False)¶

Get the canonical hash for an account/container/object

Parameters:	account – Account container – Container object – Object raw_digest – If True, return the raw version rather than a hex digest
Returns:	hash string

swift.common.utils.human_readable(value)¶: Returns the number in a human readable format; for example 1048576 = “1Mi”.

swift.common.utils.is_valid_ip(ip)¶: Return True if the provided ip is a valid IP-address

swift.common.utils.is_valid_ipv4(ip)¶: Return True if the provided ip is a valid IPv4-address

swift.common.utils.is_valid_ipv6(ip)¶: Returns True if the provided ip is a valid IPv6-address

swift.common.utils.ismount(path)¶: Test whether a path is a mount point. This will catch any exceptions and translate them into a False return value Use ismount_raw to have the exceptions raised instead.

swift.common.utils.ismount_raw(path)¶

Test whether a path is a mount point. Whereas ismount will catch any exceptions and just return False, this raw version will not catch exceptions.

This is code hijacked from C Python 2.6.8, adapted to remove the extra lstat() system call.

swift.common.utils.item_from_env(env, item_name, allow_none=False)¶

Get a value from the wsgi environment

Parameters:	env – wsgi environment dict item_name – name of item to get
Returns:	the value from the environment

swift.common.utils.iter_multipart_mime_documents(wsgi_input, boundary, read_chunk_size=4096)¶

Given a multi-part-mime-encoded input file object and boundary, yield file-like objects for each part. Note that this does not split each part into headers and body; the caller is responsible for doing that if necessary.

Parameters:	wsgi_input – The file-like object to read from. boundary – The mime boundary to separate new file-like objects on.
Returns:	A generator of file-like objects for each part.
Raises:	MimeInvalid – if the document is malformed

swift.common.utils.last_modified_date_to_timestamp(last_modified_date_str)¶: Convert a last modified date (like you’d get from a container listing, e.g. 2014-02-28T23:22:36.698390) to a float.

swift.common.utils.link_fd_to_path(fd, target_path, dirs_created=0, retries=2, fsync=True)¶

Creates a link to file descriptor at target_path specified. This method does not close the fd for you. Unlike rename, as linkat() cannot overwrite target_path if it exists, we unlink and try again.

Attempts to fix / hide race conditions like empty object directories being removed by backend processes during uploads, by retrying.

Parameters:	fd – File descriptor to be linked target_path – Path in filesystem where fd is to be linked dirs_created – Number of newly created directories that needs to be fsync’d. retries – number of retries to make fsync – fsync on containing directory of target_path and also all the newly created directories.

swift.common.utils.list_from_csv(comma_separated_str)¶: Splits the str given and returns a properly stripped list of the comma separated values.

swift.common.utils.load_libc_function(func_name, log_error=True, fail_if_missing=False, errcheck=False)¶

Attempt to find the function in libc, otherwise return a no-op func.

Parameters:	func_name – name of the function to pull from libc. log_error – log an error when a function can’t be found fail_if_missing – raise an exception when a function can’t be found. Default behavior is to return a no-op function. errcheck – boolean, if true install a wrapper on the function to check for a return values of -1 and call ctype.get_errno and raise an OSError

swift.common.utils.lock_file(*args, **kwds)¶

Context manager that acquires a lock on a file. This will block until the lock can be acquired, or the timeout time has expired (whichever occurs first).

Parameters:	filename – file to be locked timeout – timeout (in seconds) append – True if file should be opened in append mode unlink – True if the file should be unlinked at the end

swift.common.utils.lock_parent_directory(filename, timeout=10)¶

Context manager that acquires a lock on the parent directory of the given file path. This will block until the lock can be acquired, or the timeout time has expired (whichever occurs first).

Parameters:	filename – file path of the parent directory to be locked timeout – timeout (in seconds)

swift.common.utils.lock_path(*args, **kwds)¶

Context manager that acquires a lock on a directory. This will block until the lock can be acquired, or the timeout time has expired (whichever occurs first).

For locking exclusively, file or directory has to be opened in Write mode. Python doesn’t allow directories to be opened in Write Mode. So we workaround by locking a hidden file in the directory.

Parameters:	directory – directory to be locked timeout – timeout (in seconds) timeout_class – The class of the exception to raise if the lock cannot be granted within the timeout. Will be constructed as timeout_class(timeout, lockpath). Default: LockTimeout

swift.common.utils.makedirs_count(path, count=0)¶

Same as os.makedirs() except that this method returns the number of new directories that had to be created.

Also, this does not raise an error if target directory already exists. This behaviour is similar to Python 3.x’s os.makedirs() called with exist_ok=True. Also similar to swift.common.utils.mkdirs()

https://hg.python.org/cpython/file/v3.4.2/Lib/os.py#l212

swift.common.utils.maybe_multipart_byteranges_to_document_iters(app_iter, content_type)¶

Takes an iterator that may or may not contain a multipart MIME document as well as content type and returns an iterator of body iterators.

Parameters:	app_iter – iterator that may contain a multipart MIME document content_type – content type of the app_iter, used to determine whether it conains a multipart document and, if so, what the boundary is between documents

swift.common.utils.md5_hash_for_file(fname)¶

Get the MD5 checksum of a file.

Parameters:	fname – path to file
Returns:	MD5 checksum, hex encoded

swift.common.utils.mime_to_document_iters(input_file, boundary, read_chunk_size=4096)¶

Takes a file-like object containing a multipart MIME document and returns an iterator of (headers, body-file) tuples.

Parameters:	input_file – file-like object with the MIME doc in it boundary – MIME boundary, sans dashes (e.g. “divider”, not “–divider”) read_chunk_size – size of strings read via input_file.read()

swift.common.utils.mkdirs(path)¶

Ensures the path is a directory or makes it if not. Errors if the path exists but is a file or on permissions failure.

Parameters:	path – path to create

swift.common.utils.modify_priority(conf, logger)¶: Modify priority by nice and ionice.

swift.common.utils.multipart_byteranges_to_document_iters(input_file, boundary, read_chunk_size=4096)¶

Takes a file-like object containing a multipart/byteranges MIME document (see RFC 7233, Appendix A) and returns an iterator of (first-byte, last-byte, length, document-headers, body-file) 5-tuples.

Parameters:	input_file – file-like object with the MIME doc in it boundary – MIME boundary, sans dashes (e.g. “divider”, not “–divider”) read_chunk_size – size of strings read via input_file.read()

swift.common.utils.normalize_delete_at_timestamp(timestamp)¶

Format a timestamp (string or numeric) into a standardized xxxxxxxxxx (10) format.

Note that timestamps less than 0000000000 are raised to 0000000000 and values greater than November 20th, 2286 at 17:46:39 UTC will be capped at that date and time, resulting in no return value exceeding 9999999999.

This cap is because the expirer is already working through a sorted list of strings that were all a length of 10. Adding another digit would mess up the sort and cause the expirer to break from processing early. By 2286, this problem will need to be fixed, probably by creating an additional .expiring_objects account to work from with 11 (or more) digit container names.

Parameters:	timestamp – unix timestamp
Returns:	normalized timestamp as a string

swift.common.utils.normalize_timestamp(timestamp)¶

Format a timestamp (string or numeric) into a standardized xxxxxxxxxx.xxxxx (10.5) format.

Note that timestamps using values greater than or equal to November 20th, 2286 at 17:46 UTC will use 11 digits to represent the number of seconds.

Parameters:	timestamp – unix timestamp
Returns:	normalized timestamp as a string

swift.common.utils.o_tmpfile_supported()¶

Returns True if O_TMPFILE flag is supported.

O_TMPFILE was introduced in Linux 3.11 but it also requires support from underlying filesystem being used. Some common filesystems and linux versions in which those filesystems added support for O_TMPFILE: xfs (3.15) ext4 (3.11) btrfs (3.16)

swift.common.utils.override_bytes_from_content_type(listing_dict, logger=None)¶: Takes a dict from a container listing and overrides the content_type, bytes fields if swift_bytes is set.

swift.common.utils.pairs(item_list)¶

Returns an iterator of all pairs of elements from item_list.

Parameters:	item_list – items (no duplicates allowed)

swift.common.utils.parse_content_disposition(header)¶

Given the value of a header like: Content-Disposition: form-data; name=”somefile”; filename=”test.html”

Return data like (“form-data”, {“name”: “somefile”, “filename”: “test.html”})

Parameters:	header – Value of a header (the part after the ‘: ‘).
Returns:	(value name, dict) of the attribute data parsed (see above).

swift.common.utils.parse_content_range(content_range)¶

Parse a content-range header into (first_byte, last_byte, total_size).

See RFC 7233 section 4.2 for details on the header format, but it’s basically “Content-Range: bytes ${start}-${end}/${total}”.

Parameters:	content_range – Content-Range header value to parse, e.g. “bytes 100-1249/49004”
Returns:	3-tuple (start, end, total)
Raises:	ValueError – if malformed

swift.common.utils.parse_content_type(content_type)¶

Parse a content-type and its parameters into values. RFC 2616 sec 14.17 and 3.7 are pertinent.

Examples:

'text/plain; charset=UTF-8' -> ('text/plain', [('charset, 'UTF-8')])
'text/plain; charset=UTF-8; level=1' ->
    ('text/plain', [('charset, 'UTF-8'), ('level', '1')])

Parameters:	content_type – content_type to parse
Returns:	a tuple containing (content type, list of k, v parameter tuples)

swift.common.utils.parse_mime_headers(doc_file)¶

Takes a file-like object containing a MIME document and returns a HeaderKeyDict containing the headers. The body of the message is not consumed: the position in doc_file is left at the beginning of the body.

This function was inspired by the Python standard library’s http.client.parse_headers.

Parameters:	doc_file – binary file-like object containing a MIME document
Returns:	a swift.common.swob.HeaderKeyDict containing the headers

swift.common.utils.parse_options(parser=None, once=False, test_args=None)¶

Parse standard swift server/daemon options with optparse.OptionParser.

Parameters:	parser – OptionParser to use. If not sent one will be created. once – Boolean indicating the “once” option is available test_args – Override sys.argv; used in testing
Returns:	Tuple of (config, options); config is an absolute path to the config file, options is the parser options as a dictionary.
Raises:	SystemExit – First arg (CONFIG) is required, file must exist

swift.common.utils.parse_socket_string(socket_string, default_port)¶

Given a string representing a socket, returns a tuple of (host, port). Valid strings are DNS names, IPv4 addresses, or IPv6 addresses, with an optional port. If an IPv6 address is specified it must be enclosed in [], like [::1] or [::1]:11211. This follows the accepted prescription for IPv6 host literals.

Examples:

server.org
server.org:1337
127.0.0.1:1337
[::1]:1337
[::1]

swift.common.utils.public(func)¶

Decorator to declare which methods are publicly accessible as HTTP requests

Parameters:	func – function to make public

swift.common.utils.put_recon_cache_entry(cache_entry, key, item)¶: Function that will check if item is a dict, and if so put it under cache_entry[key]. We use nested recon cache entries when the object auditor runs in parallel or else in ‘once’ mode with a specified subset of devices.

swift.common.utils.quorum_size(n)¶

quorum size as it applies to services that use ‘replication’ for data integrity (Account/Container services). Object quorum_size is defined on a storage policy basis.

Number of successful backend requests needed for the proxy to consider the client request successful.

swift.common.utils.quote(value, safe=’/’)¶: Patched version of urllib.quote that encodes utf-8 strings before quoting

swift.common.utils.random() → x in the interval [0, 1).¶

swift.common.utils.ratelimit_sleep(running_time, max_rate, incr_by=1, rate_buffer=5)¶

Will eventlet.sleep() for the appropriate time so that the max_rate is never exceeded. If max_rate is 0, will not ratelimit. The maximum recommended rate should not exceed (1000 * incr_by) a second as eventlet.sleep() does involve some overhead. Returns running_time that should be used for subsequent calls.

Parameters:

running_time – the running time in milliseconds of the next allowable request. Best to start at zero.
max_rate – The maximum rate per second allowed for the process.
incr_by – How much to increment the counter. Useful if you want to ratelimit 1024 bytes/sec and have differing sizes of requests. Must be > 0 to engage rate-limiting behavior.
rate_buffer – Number of seconds the rate counter can drop and be allowed to catch up (at a faster than listed rate). A larger number will result in larger spikes in rate but better average accuracy. Must be > 0 to engage rate-limiting behavior.

swift.common.utils.readconf(conf_path, section_name=None, log_name=None, defaults=None, raw=False)¶

Read config file(s) and return config items as a dict

Parameters:	conf_path – path to config file/directory, or a file-like object (hasattr readline) section_name – config section to read (will return all sections if not defined) log_name – name to be used with logging (will use section_name if not defined) defaults – dict of default values to pre-populate the config with
Returns:	dict of config items
Raises:	ValueError – if section_name does not exist IOError – if reading the file failed

swift.common.utils.register_swift_info(name=’swift’, admin=False, **kwargs)¶

Registers information about the swift cluster to be retrieved with calls to get_swift_info.

NOTE: Do not use “.” in the param: name or any keys in kwargs. “.” is used: in the disallowed_sections to remove unwanted keys from /info.

Parameters:	name – string, the section name to place the information under. admin – boolean, if True, information will be registered to an admin section which can optionally be withheld when requesting the information. kwargs – key value arguments representing the information to be added.
Raises:	ValueError – if name or any of the keys in kwargs has “.” in it

swift.common.utils.reiterate(iterable)¶

Consume the first item from an iterator, then re-chain it to the rest of the iterator. This is useful when you want to make sure the prologue to downstream generators have been executed before continuing.

Parameters:	iterable – an iterable object

swift.common.utils.remove_file(path)¶

Quiet wrapper for os.unlink, OSErrors are suppressed

Parameters:	path – first and only argument passed to os.unlink

swift.common.utils.renamer(old, new, fsync=True)¶

Attempt to fix / hide race conditions like empty object directories being removed by backend processes during uploads, by retrying.

The containing directory of ‘new’ and of all newly created directories are fsync’d by default. This _will_ come at a performance penalty. In cases where these additional fsyncs are not necessary, it is expected that the caller of renamer() turn it off explicitly.

Parameters:	old – old path to be renamed new – new path to be renamed to fsync – fsync on containing directory of new and also all the newly created directories.

swift.common.utils.replication(func)¶

Decorator to declare which methods are accessible for different type of servers:

If option replication_server is None then this decorator doesn’t matter.
If option replication_server is True then ONLY decorated with this decorator methods will be started.
If option replication_server is False then decorated with this decorator methods will NOT be started.

Parameters:	func – function to mark accessible for replication

swift.common.utils.rsync_ip(ip)¶

Transform ip string to an rsync-compatible form

Will return ipv4 addresses unchanged, but will nest ipv6 addresses inside square brackets.

Parameters:	ip – an ip string (ipv4 or ipv6)
Returns:	a string ip address

swift.common.utils.rsync_module_interpolation(template, device)¶

Interpolate devices variables inside a rsync module template

Parameters:	template – rsync module template as a string device – a device from a ring
Returns:	a string with all variables replaced by device attributes

swift.common.utils.search_tree(root, glob_match, ext=”, exts=None, dir_ext=None)¶

Look in root, for any files/dirs matching glob, recursively traversing any found directories looking for files ending with ext

Parameters:

root – start of search path
glob_match – glob to match in root, matching dirs are traversed with os.walk
ext – only files that end in ext will be returned
exts – a list of file extensions; only files that end in one of these extensions will be returned; if set this list overrides any extension specified using the ‘ext’ param.
dir_ext – if present directories that end with dir_ext will not be traversed and instead will be returned as a matched path

Returns:

list of full paths to matching files, sorted

swift.common.utils.server_handled_successfully(status_int)¶

True for successful responses or error codes that are not Swift’s fault, False otherwise. For example, 500 is definitely the server’s fault, but 412 is an error code (4xx are all errors) that is due to a header the client sent.

If one is tracking error rates to monitor server health, one would be advised to use a function like this one, lest a client cause a flurry of 404s or 416s and make a spurious spike in your errors graph.

swift.common.utils.split_path(path, minsegs=1, maxsegs=None, rest_with_last=False)¶

Validate and split the given HTTP request path.

Examples:

['a'] = split_path('/a')
['a', None] = split_path('/a', 1, 2)
['a', 'c'] = split_path('/a/c', 1, 2)
['a', 'c', 'o/r'] = split_path('/a/c/o/r', 1, 3, True)

Parameters:	path – HTTP Request path to be split minsegs – Minimum number of segments to be extracted maxsegs – Maximum number of segments to be extracted rest_with_last – If True, trailing data will be returned as part of last segment. If False, and there is trailing data, raises ValueError.
Returns:	list of segments with a length of maxsegs (non-existent segments will return as None)
Raises:	ValueError – if given an invalid path

swift.common.utils.storage_directory(datadir, partition, name_hash)¶

Get the storage directory

Parameters:	datadir – Base data directory partition – Partition name_hash – Account, container or object name hash
Returns:	Storage directory

swift.common.utils.streq_const_time(s1, s2)¶

Constant-time string comparison.

Params s1:	the first string
Params s2:	the second string
Returns:	True if the strings are equal.

This function takes two strings and compares them. It is intended to be used when doing a comparison for authentication purposes to help guard against timing attacks.

swift.common.utils.timing_stats(**dec_kwargs)¶: Returns a decorator that logs timing events or errors for public methods in swift’s wsgi server controllers, based on response code.

swift.common.utils.tpool_reraise(func, *args, **kwargs)¶: Hack to work around Eventlet’s tpool not catching and reraising Timeouts.

swift.common.utils.unlink_older_than(path, mtime)¶

Remove any file in a given path that was last modified before mtime.

Parameters:	path – path to remove file from mtime – timestamp of oldest file to keep

swift.common.utils.unlink_paths_older_than(filepaths, mtime)¶

Remove any files from the given list that were last modified before mtime.

Parameters:	filepaths – a list of strings, the full paths of files to check mtime – timestamp of oldest file to keep

swift.common.utils.urlparse(url)¶

urlparse augmentation. This is necessary because urlparse can’t handle RFC 2732 URLs.

Parameters:	url – URL to parse.

swift.common.utils.validate_device_partition(device, partition)¶

Validate that a device and a partition are valid and won’t lead to directory traversal when used.

Parameters:	device – device to validate partition – partition to validate
Raises:	ValueError – if given an invalid device or partition

swift.common.utils.validate_sync_to(value, allowed_sync_hosts, realms_conf)¶

Validates an X-Container-Sync-To header value, returning the validated endpoint, realm, and realm_key, or an error string.

Parameters:	value – The X-Container-Sync-To header value to validate. allowed_sync_hosts – A list of allowed hosts in endpoints, if realms_conf does not apply. realms_conf – A instance of swift.common.container_sync_realms.ContainerSyncRealms to validate against.
Returns:	A tuple of (error_string, validated_endpoint, realm, realm_key). The error_string will None if the rest of the values have been validated. The validated_endpoint will be the validated endpoint to sync to. The realm and realm_key will be set if validation was done through realms_conf.

swift.common.utils.whataremyips(bind_ip=None)¶

Get “our” IP addresses (“us” being the set of services configured by one *.conf file). If our REST listens on a specific address, return it. Otherwise, if listen on ‘0.0.0.0’ or ‘::’ return all addresses, including the loopback.

Parameters:	bind_ip (str) – Optional bind_ip from a config file; may be IP address or hostname.
Returns:	list of Strings of ip addresses

swift.common.utils.write_file(path, contents)¶

Write contents to file at path

Parameters:	path – any path, subdirs will be created as needed contents – data to write to file, will be converted to string

swift.common.utils.write_pickle(obj, dest, tmp=None, pickle_protocol=0)¶

Ensure that a pickle file gets written to disk. The file is first written to a tmp location, ensure it is synced to disk, then perform a move to its final location

Parameters:	obj – python object to be pickled dest – path of final destination file tmp – path to tmp to use, defaults to None pickle_protocol – protocol to pickle the obj with, defaults to 0

WSGI¶

WSGI tools for use with swift.

class swift.common.wsgi.ConfigDirLoader(conf_dir)¶

Bases: swift.common.wsgi.NamedConfigLoader

Read configuration from multiple files under the given path.

class swift.common.wsgi.ConfigString(config_string)¶

Bases: swift.common.wsgi.NamedConfigLoader

Wrap a raw config string up for paste.deploy.

If you give one of these to our loadcontext (e.g. give it to our appconfig) we’ll intercept it and get it routed to the right loader.

class swift.common.wsgi.NamedConfigLoader(filename)¶

Bases: paste.deploy.loadwsgi.ConfigLoader

Patch paste.deploy’s ConfigLoader so each context object will know what config section it came from.

class swift.common.wsgi.PipelineWrapper(context)¶

Bases: object

This class provides a number of utility methods for modifying the composition of a wsgi pipeline.

create_filter(entry_point_name)¶

Creates a context for a filter that can subsequently be added to a pipeline context.

Parameters:	entry_point_name – entry point of the middleware (Swift only)
Returns:	a filter context

index(entry_point_name)¶

Returns the first index of the given entry point name in the pipeline.

Raises ValueError if the given module is not in the pipeline.

insert_filter(ctx, index=0)¶

Inserts a filter module into the pipeline context.

Parameters:	ctx – the context to be inserted index – (optional) index at which filter should be inserted in the list of pipeline filters. Default is 0, which means the start of the pipeline.

startswith(entry_point_name)¶

Tests if the pipeline starts with the given entry point name.

Parameters:	entry_point_name – entry point of middleware or app (Swift only)
Returns:	True if entry_point_name is first in pipeline, False otherwise

class swift.common.wsgi.PortPidState(servers_per_port, logger)¶

Bases: object

A helper class for ServersPerPortStrategy to track listen sockets and PIDs for each port.

Parameters:	servers_per_port (int) – The configured number of servers per port. logger – The server’s `LogAdaptor`

all_socks()¶: Yield all current listen sockets.

forget_pid(pid)¶

Idempotently forget a PID. It’s okay if the PID is no longer in our data structure (it could have been removed by the “orphan port” removal in new_worker_socks()).

Parameters:	pid (int) – The PID which exited.

forget_port(port)¶: Idempotently forget a port, closing the listen socket at most once.

not_tracking(port)¶

Return True if the specified port is not being tracked.

Parameters:	port (int) – A port to check.

port_for_sock(sock)¶

Parameters:	sock (socket) – A tracked bound listen socket
Returns:	The port the socket is bound to.

port_index_pairs()¶

Returns current (port, server index) pairs.

Returns:	A set of (port, server_idx) tuples for currently-tracked ports, sockets, and PIDs.

sock_for_port(port)¶

Parameters:	port (int) – The port whose socket is desired.
Returns:	The bound listen socket for the given port.

track_port(port, sock)¶

Start tracking servers for the given port and listen socket.

Parameters:	port (int) – The port to start tracking sock (socket) – The bound listen socket for the port.

class swift.common.wsgi.RestrictedGreenPool(size=1024)¶

Bases: eventlet.greenpool.GreenPool

Works the same as GreenPool, but if the size is specified as one, then the spawn_n() method will invoke waitall() before returning to prevent the caller from doing any other work (like calling accept()).

class swift.common.wsgi.ServersPerPortStrategy(conf, logger, servers_per_port)¶

Bases: object

WSGI server management strategy object for an object-server with one listen port per unique local port in the storage policy rings. The servers_per_port integer config setting determines how many workers are run per port.

Used in run_wsgi().

Parameters:	conf (dict) – Server configuration dictionary. logger – The server’s `LogAdaptor` object. servers_per_port (int) – The number of workers to run per port.

bind_ports()¶: Bind one listen socket per unique local storage policy ring port. Then do all the work of drop_privileges except the actual dropping of privileges (each forked-off worker will do that post-fork in post_fork_hook()).

log_sock_exit(sock, server_idx)¶: Log a server’s exit.

loop_timeout()¶

Return timeout before checking for reloaded rings.

Returns:	The time to wait for a child to exit before checking for reloaded rings (new ports).

new_worker_socks()¶

Yield a sequence of (socket, server_idx) tuples for each server which should be forked-off and started.

Any sockets for “orphaned” ports no longer in any ring will be closed (causing their associated workers to gracefully exit) after all new sockets have been yielded.

The server_idx item for each socket will passed into the log_sock_exit() and register_worker_start() methods.

no_fork_sock()¶: This strategy does not support running in the foreground.

post_fork_hook()¶: Called in each child process, prior to starting the actual wsgi server, to drop privileges.

register_worker_exit(pid)¶

Called when a worker has exited.

Parameters:	pid (int) – The PID of the worker that exited.

register_worker_start(sock, server_idx, pid)¶

Called when a new worker is started.

Parameters:	sock (socket) – The listen socket for the worker just started. server_idx – The socket’s server_idx as yielded by `new_worker_socks()`. pid (int) – The new worker process’ PID

shutdown_sockets()¶: Shutdown any listen sockets.

class swift.common.wsgi.WSGIContext(wsgi_app)¶

Bases: object

This class provides a means to provide context (scope) for a middleware filter to have access to the wsgi start_response results like the request status and headers.

class swift.common.wsgi.WorkersStrategy(conf, logger)¶

Bases: object

WSGI server management strategy object for a single bind port and listen socket shared by a configured number of forked-off workers.

Used in run_wsgi().

Parameters:	conf (dict) – Server configuration dictionary. logger – The server’s `LogAdaptor` object.

bind_ports()¶: Bind the one listen socket for this strategy and drop privileges (since the parent process will never need to bind again).

log_sock_exit(sock, _unused)¶

Log a server’s exit.

Parameters:	sock (socket) – The listen socket for the worker just started. _unused – The socket’s opaque_data yielded by `new_worker_socks()`.

loop_timeout()¶

We want to keep from busy-waiting, but we also need a non-None value so the main loop gets a chance to tell whether it should keep running or not (e.g. SIGHUP received).

So we return 0.5.

new_worker_socks()¶

Yield a sequence of (socket, opqaue_data) tuples for each server which should be forked-off and started.

The opaque_data item for each socket will passed into the log_sock_exit() and register_worker_start() methods where it will be ignored.

no_fork_sock()¶: Return a server listen socket if the server should run in the foreground (no fork).

post_fork_hook()¶: Perform any initialization in a forked-off child process prior to starting the wsgi server.

register_worker_exit(pid)¶

Called when a worker has exited.

Parameters:	pid (int) – The PID of the worker that exited.

register_worker_start(sock, _unused, pid)¶

Called when a new worker is started.

Parameters:	sock (socket) – The listen socket for the worker just started. _unused – The socket’s opaque_data yielded by new_worker_socks(). pid (int) – The new worker process’ PID

shutdown_sockets()¶: Shutdown any listen sockets.

swift.common.wsgi.get_socket(conf)¶

Bind socket to bind ip:port in conf

Parameters:	conf – Configuration dict to read settings from
Returns:	a socket object as returned from socket.listen or ssl.wrap_socket if conf specifies cert_file

swift.common.wsgi.init_request_processor(conf_path, app_section, *args, **kwargs)¶

Loads common settings from conf Sets the logger Loads the request processor

Parameters:	conf_path – Path to paste.deploy style configuration file/directory app_section – App name from conf file to load config from
Returns:	the loaded application entry point
Raises:	ConfigFileError – Exception is raised for config file error

swift.common.wsgi.loadapp(conf_file, global_conf=None, allow_modify_pipeline=True)¶: Loads a context from a config file, and if the context is a pipeline then presents the app with the opportunity to modify the pipeline.

swift.common.wsgi.make_env(env, method=None, path=None, agent=’Swift’, query_string=None, swift_source=None)¶

Returns a new fresh WSGI environment.

Parameters:

env – The WSGI environment to base the new environment on.
method – The new REQUEST_METHOD or None to use the original.
path – The new path_info or none to use the original. path should NOT be quoted. When building a url, a Webob Request (in accordance with wsgi spec) will quote env[‘PATH_INFO’]. url += quote(environ[‘PATH_INFO’])
query_string – The new query_string or none to use the original. When building a url, a Webob Request will append the query string directly to the url. url += ‘?’ + env[‘QUERY_STRING’]
agent – The HTTP user agent to use; default ‘Swift’. You can put %(orig)s in the agent to have it replaced with the original env’s HTTP_USER_AGENT, such as ‘%(orig)s StaticWeb’. You also set agent to None to use the original env’s HTTP_USER_AGENT or ” to have no HTTP_USER_AGENT.
swift_source – Used to mark the request as originating out of middleware. Will be logged in proxy logs.

Returns:

Fresh WSGI environment.

swift.common.wsgi.make_pre_authed_env(env, method=None, path=None, agent=’Swift’, query_string=None, swift_source=None)¶: Same as make_env() but with preauthorization.

swift.common.wsgi.make_pre_authed_request(env, method=None, path=None, body=None, headers=None, agent=’Swift’, swift_source=None)¶: Same as make_subrequest() but with preauthorization.

swift.common.wsgi.make_subrequest(env, method=None, path=None, body=None, headers=None, agent=’Swift’, swift_source=None, make_env=<function make_env>)¶

Makes a new swob.Request based on the current env but with the parameters specified.

Parameters:

env – The WSGI environment to base the new request on.
method – HTTP method of new request; default is from the original env.
path – HTTP path of new request; default is from the original env. path should be compatible with what you would send to Request.blank. path should be quoted and it can include a query string. for example: ‘/a%20space?unicode_str%E8%AA%9E=y%20es’
body – HTTP body of new request; empty by default.
headers – Extra HTTP headers of new request; None by default.
agent – The HTTP user agent to use; default ‘Swift’. You can put %(orig)s in the agent to have it replaced with the original env’s HTTP_USER_AGENT, such as ‘%(orig)s StaticWeb’. You also set agent to None to use the original env’s HTTP_USER_AGENT or ” to have no HTTP_USER_AGENT.
swift_source – Used to mark the request as originating out of middleware. Will be logged in proxy logs.
make_env – make_subrequest calls this make_env to help build the swob.Request.

Returns:

Fresh swob.Request object.

swift.common.wsgi.monkey_patch_mimetools()¶: mimetools.Message defaults content-type to “text/plain” This changes it to default to None, so we can detect missing headers.

swift.common.wsgi.pipeline_property(name, **kwargs)¶

Create a property accessor for the given name. The property will dig through the bound instance on which it was accessed for an attribute “app” and check that object for an attribute of the given name. If the “app” object does not have such an attribute, it will look for an attribute “app” on THAT object and continue it’s search from there. If the named attribute cannot be found accessing the property will raise AttributeError.

If a default kwarg is provided you get that instead of the AttributeError. When found the attribute will be cached on instance with the property accessor using the same name as the attribute prefixed with a leading underscore.

swift.common.wsgi.run_wsgi(conf_path, app_section, *args, **kwargs)¶

Runs the server according to some strategy. The default strategy runs a specified number of workers in pre-fork model. The object-server (only) may use a servers-per-port strategy if its config has a servers_per_port setting with a value greater than zero.

Parameters:	conf_path – Path to paste.deploy style configuration file/directory app_section – App name from conf file to load config from
Returns:	0 if successful, nonzero otherwise

swift.common.wsgi.wrap_conf_type(f)¶: Wrap a function whos first argument is a paste.deploy style config uri, such that you can pass it an un-adorned raw filesystem path (or config string) and the config directive (either config:, config_dir:, or config_str:) will be added automatically based on the type of entity (either a file or directory, or if no such entity on the file system - just a string) before passing it through to the paste.deploy function.

Storage Policy¶

class swift.common.storage_policy.BaseStoragePolicy(idx, name=”, is_default=False, is_deprecated=False, object_ring=None, aliases=”)¶

Bases: object

Represents a storage policy. Not meant to be instantiated directly; implement a derived subclasses (e.g. StoragePolicy, ECStoragePolicy, etc) or use reload_storage_policies() to load POLICIES from swift.conf.

The object_ring property is lazy loaded once the service’s swift_dir is known via get_object_ring(), but it may be over-ridden via object_ring kwarg at create time for testing or actively loaded with load_ring().

add_name(name)¶

Adds an alias name to the storage policy. Shouldn’t be called directly from the storage policy but instead through the storage policy collection class, so lookups by name resolve correctly.

Parameters:	name – a new alias for the storage policy

change_primary_name(name)¶

Changes the primary/default name of the policy to a specified name.

Parameters:	name – a string name to replace the current primary name.

get_info(config=False)¶

Return the info dict and conf file options for this policy.

Parameters:	config – boolean, if True all config options are returned

load_ring(swift_dir)¶

Load the ring for this policy immediately.

Parameters:	swift_dir – path to rings

quorum¶: Number of successful backend requests needed for the proxy to consider the client request successful.

classmethod register(policy_type)¶: Decorator for Storage Policy implementations to register their StoragePolicy class. This will also set the policy_type attribute on the registered implementation.

remove_name(name)¶

Removes an alias name from the storage policy. Shouldn’t be called directly from the storage policy but instead through the storage policy collection class, so lookups by name resolve correctly. If the name removed is the primary name then the next available alias will be adopted as the new primary name.

Parameters:	name – a name assigned to the storage policy

class swift.common.storage_policy.ECStoragePolicy(idx, name=”, aliases=”, is_default=False, is_deprecated=False, object_ring=None, ec_segment_size=1048576, ec_type=None, ec_ndata=None, ec_nparity=None, ec_duplication_factor=1)¶

Bases: swift.common.storage_policy.BaseStoragePolicy

Represents a storage policy of type ‘erasure_coding’.

Not meant to be instantiated directly; use reload_storage_policies() to load POLICIES from swift.conf.

ec_scheme_description¶: This short hand form of the important parts of the ec schema is stored in Object System Metadata on the EC Fragment Archives for debugging.

fragment_size¶

Maximum length of a fragment, including header.

NB: a fragment archive is a sequence of 0 or more max-length fragments followed by one possibly-shorter fragment.

get_backend_index(node_index)¶

Backend index for PyECLib

Parameters:	node_index – integer of node index
Returns:	integer of actual fragment index. if param is not an integer, return None instead

load_ring(swift_dir)¶

Load the ring for this policy immediately.

Parameters:	swift_dir – path to rings

quorum¶

Number of successful backend requests needed for the proxy to consider the client PUT request successful.

The quorum size for EC policies defines the minimum number of data + parity elements required to be able to guarantee the desired fault tolerance, which is the number of data elements supplemented by the minimum number of parity elements required by the chosen erasure coding scheme.

For example, for Reed-Solomon, the minimum number parity elements required is 1, and thus the quorum_size requirement is ec_ndata + 1.

Given the number of parity elements required is not the same for every erasure coding scheme, consult PyECLib for min_parity_fragments_needed()

class swift.common.storage_policy.StoragePolicy(idx, name=”, is_default=False, is_deprecated=False, object_ring=None, aliases=”)¶

Bases: swift.common.storage_policy.BaseStoragePolicy

Represents a storage policy of type ‘replication’. Default storage policy class unless otherwise overridden from swift.conf.

Not meant to be instantiated directly; use reload_storage_policies() to load POLICIES from swift.conf.

quorum¶

Quorum concept in the replication case:: floor(number of replica / 2) + 1

class swift.common.storage_policy.StoragePolicyCollection(pols)¶

Bases: object

This class represents the collection of valid storage policies for the cluster and is instantiated as StoragePolicy objects are added to the collection when swift.conf is parsed by parse_storage_policies().

When a StoragePolicyCollection is created, the following validation is enforced:

If a policy with index 0 is not declared and no other policies defined, Swift will create one
The policy index must be a non-negative integer
If no policy is declared as the default and no other policies are defined, the policy with index 0 is set as the default
Policy indexes must be unique
Policy names are required
Policy names are case insensitive
Policy names must contain only letters, digits or a dash
Policy names must be unique
The policy name ‘Policy-0’ can only be used for the policy with index 0
If any policies are defined, exactly one policy must be declared default
Deprecated policies can not be declared the default

add_policy_alias(policy_index, *aliases)¶

Adds a new name or names to a policy

Parameters:	policy_index – index of a policy in this policy collection. aliases – arbitrary number of string policy names to add.

change_policy_primary_name(policy_index, new_name)¶

Changes the primary or default name of a policy. The new primary name can be an alias that already belongs to the policy or a completely new name.

Parameters:	policy_index – index of a policy in this policy collection. new_name – a string name to set as the new default name.

get_by_index(index)¶

Find a storage policy by its index.

An index of None will be treated as 0.

Parameters:	index – numeric index of the storage policy
Returns:	storage policy, or None if no such policy

get_by_name(name)¶

Find a storage policy by its name.

Parameters:	name – name of the policy
Returns:	storage policy, or None

get_object_ring(policy_idx, swift_dir)¶

Get the ring object to use to handle a request based on its policy.

An index of None will be treated as 0.

Parameters:	policy_idx – policy index as defined in swift.conf swift_dir – swift_dir used by the caller
Returns:	appropriate ring object

get_policy_info()¶

Build info about policies for the /info endpoint

Returns:	list of dicts containing relevant policy information

remove_policy_alias(*aliases)¶

Removes a name or names from a policy. If the name removed is the primary name then the next available alias will be adopted as the new primary name.

Parameters:	aliases – arbitrary number of existing policy names to remove.

class swift.common.storage_policy.StoragePolicySingleton¶

Bases: object

An instance of this class is the primary interface to storage policies exposed as a module level global named POLICIES. This global reference wraps _POLICIES which is normally instantiated by parsing swift.conf and will result in an instance of StoragePolicyCollection.

You should never patch this instance directly, instead patch the module level _POLICIES instance so that swift code which imported POLICIES directly will reference the patched StoragePolicyCollection.

swift.common.storage_policy.get_policy_string(base, policy_or_index)¶

Helper function to construct a string from a base and the policy. Used to encode the policy index into either a file name or a directory name by various modules.

Parameters:	base – the base string policy_or_index – StoragePolicy instance, or an index (string or int), if None the legacy storage Policy-0 is assumed.
Returns:	base name with policy index added
Raises:	PolicyError – if no policy exists with the given policy_index

swift.common.storage_policy.parse_storage_policies(conf)¶

Parse storage policies in swift.conf - note that validation is done when the StoragePolicyCollection is instantiated.

Parameters:	conf – ConfigParser parser object for swift.conf

swift.common.storage_policy.reload_storage_policies()¶: Reload POLICIES from swift.conf.

swift.common.storage_policy.split_policy_string(policy_string)¶

Helper function to convert a string representing a base and a policy. Used to decode the policy from either a file name or a directory name by various modules.

Parameters:	policy_string – base name with policy index added
Raises:	PolicyError – if given index does not map to a valid policy
Returns:	a tuple, in the form (base, policy) where base is the base string and policy is the StoragePolicy instance for the index encoded in the policy_string.

OpenStack

Misc¶

ACLs¶

Buffered HTTP¶

Constraints¶

Container Sync Realms¶

Direct Client¶

Exceptions¶

Internal Client¶

Manager¶

MemCacheD¶

Request Helpers¶

Swob¶

Utils¶

WSGI¶

Storage Policy¶

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OpenStack

Misc¶

ACLs¶

Buffered HTTP¶

Constraints¶

Container Sync Realms¶

Direct Client¶

Exceptions¶

Internal Client¶

Manager¶

MemCacheD¶

Request Helpers¶

Swob¶

Utils¶

WSGI¶

Storage Policy¶

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