borgmatic-collective/borgmatic
borgmatic-collective/borgmatic
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Factoring out some utility functions (#261).

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This commit is contained in:
Dan Helfman 2024-11-21 20:17:57 -08:00
parent ab7acceff6
commit 87f36caf8d
2 changed files with 73 additions and 48 deletions
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2
borgmatic/config/paths.py
View File

@ -55,7 +55,7 @@ def replace_temporary_subdirectory_with_glob(path):
else subdirectory
)
for subdirectory in path.split(os.path.sep)
)
),
)

119
borgmatic/hooks/zfs.py
View File

@ -22,6 +22,71 @@ BORGMATIC_SNAPSHOT_PREFIX = 'borgmatic-'
BORGMATIC_USER_PROPERTY = 'org.torsion.borgmatic:backup'
def get_datasets_to_backup(zfs_command, source_directories):
'''
Given a ZFS command to run and a sequence of configured source directories, find the
intersection between the current ZFS dataset mount points and the configured borgmatic source
directories. The idea is that these are the requested datasets to snapshot. But also include any
datasets tagged with a borgmatic-specific user property whether or not they appear in source
directories.
Return the result as a sequence of (dataset name, mount point) pairs.
'''
list_command = (
zfs_command,
'list',
'-H',
'-t',
'filesystem',
'-o',
f'name,mountpoint,{BORGMATIC_USER_PROPERTY}',
)
list_output = borgmatic.execute.execute_command_and_capture_output(list_command)
source_directories_set = set(source_directories)
return tuple(
(dataset_name, mount_point)
for line in list_output.splitlines()
for (dataset_name, mount_point, user_property_value) in (line.rstrip().split('\t'),)
if mount_point in source_directories_set or user_property_value == 'auto'
)
def snapshot_dataset(zfs_command, full_snapshot_name):
'''
Given a ZFS command to run and a snapshot name of the form "dataset@snapshot", create a new ZFS
snapshot.
'''
borgmatic.execute.execute_command(
(
zfs_command,
'snapshot',
'-r',
full_snapshot_name,
),
output_log_level=logging.DEBUG,
)
def mount_snapshot(mount_command, full_snapshot_name, snapshot_mount_path):
'''
Given a mount command to run, an existing snapshot name of the form "dataset@snapshot", and the
path where the snapshot should be mounted, mount the snapshot (making any necessary directories
first).
'''
os.makedirs(snapshot_mount_path, mode=0o700, exist_ok=True)
borgmatic.execute.execute_command(
(
mount_command,
'-t',
'zfs',
full_snapshot_name,
snapshot_mount_path,
),
output_log_level=logging.DEBUG,
)
def dump_data_sources(
hook_config,
config,
@ -47,31 +112,9 @@ def dump_data_sources(
# List ZFS datasets to get their mount points.
zfs_command = hook_config.get('zfs_command', 'zfs')
list_command = (
zfs_command,
'list',
'-H',
'-t',
'filesystem',
'-o',
f'name,mountpoint,{BORGMATIC_USER_PROPERTY}',
)
list_output = borgmatic.execute.execute_command_and_capture_output(list_command)
source_directories_set = set(source_directories)
# Find the intersection between the dataset mount points and the configured borgmatic source
# directories, the idea being that these are the requested datasets to snapshot. But also
# include any datasets tagged with a borgmatic-specific user property whether or not they
# appear in source directories.
requested_datasets = tuple(
(dataset_name, mount_point)
for line in list_output.splitlines()
for (dataset_name, mount_point, user_property_value) in (line.rstrip().split('\t'),)
if mount_point in source_directories_set or user_property_value == 'auto'
)
requested_datasets = get_datasets_to_backup(zfs_command, source_directories)
# Snapshot each dataset, rewriting source directories to use the snapshot paths.
snapshot_paths = []
snapshot_name = f'{BORGMATIC_SNAPSHOT_PREFIX}{os.getpid()}'
for dataset_name, mount_point in requested_datasets:
@ -79,46 +122,28 @@ def dump_data_sources(
logger.debug(f'{log_prefix}: Creating ZFS snapshot {full_snapshot_name}{dry_run_label}')
if not dry_run:
borgmatic.execute.execute_command(
(
zfs_command,
'snapshot',
'-r',
full_snapshot_name,
),
output_log_level=logging.DEBUG,
)
snapshot_dataset(zfs_command, full_snapshot_name)
# Mount the snapshot into a particular named temporary directory so that the snapshot ends
# up in the Borg archive at the "original" dataset mount point path.
snapshot_path_for_borg = os.path.join(
snapshot_mount_path_for_borg = os.path.join(
os.path.normpath(borgmatic_runtime_directory),
'zfs_snapshots',
'.',
mount_point.lstrip(os.path.sep),
)
snapshot_path = os.path.normpath(snapshot_path_for_borg)
snapshot_mount_path = os.path.normpath(snapshot_mount_path_for_borg)
logger.debug(
f'{log_prefix}: Mounting ZFS snapshot {full_snapshot_name} at {snapshot_path}{dry_run_label}'
f'{log_prefix}: Mounting ZFS snapshot {full_snapshot_name} at {snapshot_mount_path}{dry_run_label}'
)
if not dry_run:
os.makedirs(snapshot_path, mode=0o700, exist_ok=True)
borgmatic.execute.execute_command(
(
hook_config.get('mount_command', 'mount'),
'-t',
'zfs',
f'{dataset_name}@{snapshot_name}',
snapshot_path,
),
output_log_level=logging.DEBUG,
)
mount_snapshot(hook_config.get('mount_command', 'mount'), full_snapshot_name, snapshot_mount_path)
if mount_point in source_directories:
source_directories.remove(mount_point)
source_directories.append(snapshot_path_for_borg)
source_directories.append(snapshot_mount_path_for_borg)
return []