freezer.engine.engine module¶
- class freezer.engine.engine.BackupEngine(storage)¶
Bases:
object
The main part of making a backup and making a restore is the mechanism of implementing it. For a long time Freezer had only one mechanism of doing it - invoking gnutar and it was heavy hard-coded.
Currently we are going to support many different approaches. One of them is rsync. Having many different implementations requires to have an abstraction level
This class is an abstraction over all implementations.
Workflow:
invoke backup
try to download metadata for incremental
create a dataflow between backup_stream and storage.write_backup Backup_stream is producer of data, for tar backup it creates a gnutar subprocess and start to read data from stdout Storage write_backup is consumer of data, it creates a thread that store data in storage. Both streams communicate in non-blocking mode
invoke post_backup - now it uploads metadata file
restore backup
define all incremental backups
for each incremental backup create a dataflow between storage.read_backup and restore_stream Read_backup is data producer, it reads data chunk by chunk from the specified storage and pushes the chunks into a queue. Restore stream is a consumer, that is actually does restore (for tar it is a thread that creates gnutar subprocess and feeds chunks to stdin of this thread.
- backup(backup_resource, hostname_backup_name, no_incremental, max_level, always_level, restart_always_level, queue_size=2)¶
Here we now location of all interesting artifacts like metadata Should return stream for storing data. :return: stream
- abstract backup_data(backup_path, manifest_path)¶
- Parameters
backup_path –
manifest_path –
- Returns
- backup_stream(backup_resource, rich_queue, manifest_path)¶
- Parameters
rich_queue (freezer.streaming.RichQueue) –
manifest_path (list[str]) –
- Returns
- abstract metadata(backup_resource)¶
- abstract property name¶
- Return type
str
- Returns
Engine name
- read_blocks(backup, write_pipe, read_pipe, except_queue)¶
- restore(hostname_backup_name, restore_resource, overwrite, recent_to_date, backup_media=None)¶
- Parameters
hostname_backup_name –
restore_path –
overwrite –
recent_to_date –
- abstract restore_level(restore_path, read_pipe, backup, except_queue)¶