borgmatic/atticmatic/backends/shared.py

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from datetime import datetime
import os
import re
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import platform
import subprocess
from atticmatic.config import Section_format, option
from atticmatic.verbosity import VERBOSITY_SOME, VERBOSITY_LOTS
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# Common backend functionality shared by Attic and Borg. As the two backup
# commands diverge, these shared functions will likely need to be replaced
# with non-shared functions within atticmatic.backends.attic and
# atticmatic.backends.borg.
CONFIG_FORMAT = (
Section_format(
'location',
(
option('source_directories'),
option('repository'),
),
),
Section_format(
'storage',
(
option('encryption_passphrase', required=False),
),
),
Section_format(
'retention',
(
option('keep_within', required=False),
option('keep_hourly', int, required=False),
option('keep_daily', int, required=False),
option('keep_weekly', int, required=False),
option('keep_monthly', int, required=False),
option('keep_yearly', int, required=False),
option('prefix', required=False),
),
),
Section_format(
'consistency',
(
option('checks', required=False),
),
)
)
def initialize(storage_config, command):
passphrase = storage_config.get('encryption_passphrase')
if passphrase:
os.environ['{}_PASSPHRASE'.format(command.upper())] = passphrase
def create_archive(
excludes_filename, verbosity, storage_config, source_directories, repository, command,
one_file_system=None,
):
'''
Given an excludes filename (or None), a vebosity flag, a storage config dict, a space-separated
list of source directories, a local or remote repository path, and a command to run, create an
attic archive.
'''
sources = tuple(re.split('\s+', source_directories))
exclude_flags = ('--exclude-from', excludes_filename) if excludes_filename else ()
compression = storage_config.get('compression', None)
compression_flags = ('--compression', compression) if compression else ()
one_file_system_flags = ('--one-file-system',) if one_file_system else ()
verbosity_flags = {
VERBOSITY_SOME: ('--stats',),
VERBOSITY_LOTS: ('--verbose', '--stats'),
}.get(verbosity, ())
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full_command = (
command, 'create',
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'{repo}::{hostname}-{timestamp}'.format(
repo=repository,
hostname=platform.node(),
timestamp=datetime.now().isoformat(),
),
) + sources + exclude_flags + compression_flags + one_file_system_flags + \
verbosity_flags
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subprocess.check_call(full_command)
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def _make_prune_flags(retention_config):
'''
Given a retention config dict mapping from option name to value, tranform it into an iterable of
command-line name-value flag pairs.
For example, given a retention config of:
{'keep_weekly': 4, 'keep_monthly': 6}
This will be returned as an iterable of:
(
('--keep-weekly', '4'),
('--keep-monthly', '6'),
)
'''
return (
('--' + option_name.replace('_', '-'), str(retention_config[option_name]))
for option_name, value in retention_config.items()
)
def prune_archives(verbosity, repository, retention_config, command):
'''
Given a verbosity flag, a local or remote repository path, a retention config dict, and a
command to run, prune attic archives according the the retention policy specified in that
configuration.
'''
verbosity_flags = {
VERBOSITY_SOME: ('--stats',),
VERBOSITY_LOTS: ('--verbose', '--stats'),
}.get(verbosity, ())
full_command = (
command, 'prune',
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repository,
) + tuple(
element
for pair in _make_prune_flags(retention_config)
for element in pair
) + verbosity_flags
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subprocess.check_call(full_command)
DEFAULT_CHECKS = ('repository', 'archives')
def _parse_checks(consistency_config):
'''
Given a consistency config with a space-separated "checks" option, transform it to a tuple of
named checks to run.
For example, given a retention config of:
{'checks': 'repository archives'}
This will be returned as:
('repository', 'archives')
If no "checks" option is present, return the DEFAULT_CHECKS. If the checks value is the string
"disabled", return an empty tuple, meaning that no checks should be run.
'''
checks = consistency_config.get('checks', '').strip()
if not checks:
return DEFAULT_CHECKS
return tuple(
check for check in consistency_config['checks'].split(' ')
if check.lower() not in ('disabled', '')
)
def _make_check_flags(checks, check_last=None):
'''
Given a parsed sequence of checks, transform it into tuple of command-line flags.
For example, given parsed checks of:
('repository',)
This will be returned as:
('--repository-only',)
Additionally, if a check_last value is given, a "--last" flag will be added. Note that only
Borg supports this flag.
'''
last_flag = ('--last', check_last) if check_last else ()
if checks == DEFAULT_CHECKS:
return last_flag
return tuple(
'--{}-only'.format(check) for check in checks
) + last_flag
def check_archives(verbosity, repository, consistency_config, command):
'''
Given a verbosity flag, a local or remote repository path, a consistency config dict, and a
command to run, check the contained attic archives for consistency.
If there are no consistency checks to run, skip running them.
'''
checks = _parse_checks(consistency_config)
check_last = consistency_config.get('check_last', None)
if not checks:
return
verbosity_flags = {
VERBOSITY_SOME: ('--verbose',),
VERBOSITY_LOTS: ('--verbose',),
}.get(verbosity, ())
full_command = (
command, 'check',
repository,
) + _make_check_flags(checks, check_last) + verbosity_flags
# The check command spews to stdout even without the verbose flag. Suppress it.
stdout = None if verbosity_flags else open(os.devnull, 'w')
subprocess.check_call(full_command, stdout=stdout)