oslo_config.sources package¶
Module contents¶
Oslo.config’s primary source of configuration data are plaintext, INI-like style, configuration files. With the addition of backend drivers support, it is possible to store configuration data in different places and with different formats, as long as there exists a proper driver to connect to those external sources and provide a way to fetch configuration values from them.
A backend driver implementation is divided in two main classes, a driver
class of type ConfigurationSourceDriver
and a configuration source
class of type ConfigurationSource
.
IMPORTANT: At this point, all backend drivers are only able to provide immutable values. This protects applications and services from having options in external sources mutated when they reload configuration files.
-
class
oslo_config.sources.
ConfigurationSource
¶ Bases:
object
A configuration source option for oslo.config.
A configuration source is able to fetch configuration values based on a (group, option) key from an external source that supports key-value mapping such as INI files, key-value stores, secret stores, and so on.
-
abstract
get
(group_name, option_name, opt)¶ Return the value of the option from the group.
- Parameters
group_name (str) – Name of the group.
option_name (str) – Name of the option.
opt (Opt) – The option definition.
- Returns
A tuple (value, location) where value is the option value or oslo_config.sources._NoValue if the (group, option) is not present in the source, and location is a LocationInfo.
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abstract
-
class
oslo_config.sources.
ConfigurationSourceDriver
¶ Bases:
object
A backend driver option for oslo.config.
For each group name listed in config_source on the DEFAULT group, a
ConfigurationSourceDriver
is responsible for creating one new instance of aConfigurationSource
. The proper driver class to be used is selected based on the driver option inside each one of the groups listed in config_source and loaded through entry points managed by stevedore using the namespace oslo.config.driver:[DEFAULT] config_source = source1 config_source = source2 ... [source1] driver = remote_file ... [source2] driver = castellan ...
Each specific driver knows all the available options to properly instatiate a ConfigurationSource using the values comming from the given group in the open_source_from_opt_group() method and is able to generate sample config through the list_options_for_discovery() method.
-
abstract
list_options_for_discovery
()¶ Return the list of options available to configure a new source.
Drivers should advertise all supported options in this method for the purpose of sample generation by oslo-config-generator.
For an example on how to implement this method you can check the remote_file driver at oslo_config.sources._uri.URIConfigurationSourceDriver.
- Returns
a list of supported options of a ConfigurationSource.
-
abstract
open_source_from_opt_group
(conf, group_name)¶ Return an open configuration source.
Uses group_name to find the configuration settings for the new source and then open the configuration source and return it.
If a source cannot be open, raises an appropriate exception.
- Parameters
conf (ConfigOpts) – The active configuration option handler from which to seek configuration values.
group_name (str) – The configuration option group name where the options for the source are stored.
- Returns
an instance of a subclass of ConfigurationSource
-
abstract