kevinveenbirkenbach/docker-volume-backup
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feat(manifest)!: record per volume what the run established

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A finished generation cannot show whether a volume held a database, nor whether a dump was produced for it: under --only-sql a failed dump falls back to a file copy, and the resulting files/ tree looks like any other copy. The run knows both and threw the knowledge away as a printed warning, leaving every reader to guess from file names.

Each generation now carries a manifest.json stating its layout and, per volume, database / dumped / engine. baudolo.generation is the single place those names are spelled; restore/paths.py, backup/db.py and backup/volume.py stop repeating them. It is deliberately import-free so a consumer can read the manifest with nothing but json, on hosts where this package is not installed.

BREAKING CHANGE: BackupException is renamed BackupError. The rename is atomic across the ten modules that define or import it, three of which also carry the manifest change, so it lands in this commit rather than a separate one that could not import.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Kevin Veen-Birkenbach
2026-08-18 01:47:38 +02:00
parent 03da186a06
commit 94637c32aa
22 changed files with 422 additions and 106 deletions
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19
src/baudolo/backup/app.py
View File

@@ -2,9 +2,9 @@
from __future__ import annotations
import os
from contextlib import ExitStack
from datetime import datetime
from pathlib import Path
from .cli import parse_args
from .compose import handle_docker_compose_services
@@ -14,12 +14,13 @@ from .docker import (
docker_volume_names,
filter_stoppable,
)
from .dumps import backup_dumps_for_volume, load_databases_df
from .dumps import VolumeOutcome, backup_dumps_for_volume, load_databases_df
from .layout import (
create_version_directory,
create_volume_directory,
get_machine_id,
stamp_directory,
write_manifest,
)
from .policy import requires_stop, volume_is_fully_ignored
from .snapshot import snapshot_source, volume_snapshot
@@ -34,13 +35,15 @@ def main() -> int:
# order new ones before the existing ones wherever the offset is positive.
backup_time = datetime.now().strftime("%Y%m%d%H%M%S") # noqa: DTZ005
versions_dir = os.path.join(args.backups_dir, machine_id, args.repo_name)
versions_dir = str(Path(args.backups_dir) / machine_id / args.repo_name)
version_dir = create_version_directory(versions_dir, backup_time)
databases_df = None if args.only_files else load_databases_df(args.databases_csv)
print("💾 Start volume backups...", flush=True)
outcomes: dict[str, VolumeOutcome] = {}
with ExitStack() as stack:
resolve_source = None
if args.snapshot:
@@ -69,17 +72,18 @@ def main() -> int:
vol_dir = create_volume_directory(version_dir, volume_name)
found_db = dumped_any = False
outcome = VolumeOutcome(database=False, dumped=False)
if not args.only_files:
found_db, dumped_any = backup_dumps_for_volume(
outcome = backup_dumps_for_volume(
containers=containers,
vol_dir=vol_dir,
databases_df=databases_df,
database_containers=args.database_containers,
)
outcomes[volume_name] = outcome
if args.only_sql and found_db:
if not dumped_any:
if args.only_sql and outcome.database:
if not outcome.dumped:
print(
f"WARNING: only-sql requested but no DB dump was produced for DB volume '{volume_name}'. "
"Falling back to file backup.",
@@ -129,6 +133,7 @@ def main() -> int:
if not args.shutdown:
change_containers_status(stoppable, "start")
write_manifest(version_dir, outcomes)
stamp_directory(version_dir)
print("Finished volume backups.", flush=True)

26
src/baudolo/backup/db.py
View File

@@ -1,16 +1,18 @@
from __future__ import annotations
import logging
import os
import pathlib
import re
import pandas
from typing import TYPE_CHECKING
from baudolo.databases import CLUSTER_ROW, validate_database
from baudolo.generation import CLUSTER_SUFFIX, DUMP_SUFFIX, SQL_DIR
from .docker import docker_exec_argv
from .shell import BackupException, execute_to_file
from .shell import BackupError, execute_to_file
if TYPE_CHECKING:
import pandas as pd
log = logging.getLogger(__name__)
@@ -47,7 +49,7 @@ def backup_database(
volume_dir: str,
db_type: str,
dump_tool: str,
databases_df: pandas.DataFrame,
databases_df: pd.DataFrame,
database_containers: list[str],
) -> bool:
"""
@@ -66,8 +68,8 @@ def backup_database(
log.debug("No database entries for instance '%s'", instance_name)
return False
out_dir = os.path.join(volume_dir, "sql")
pathlib.Path(out_dir).mkdir(parents=True, exist_ok=True)
out_dir = pathlib.Path(volume_dir) / SQL_DIR
out_dir.mkdir(parents=True, exist_ok=True)
produced = False
@@ -85,13 +87,13 @@ def backup_database(
f"'{CLUSTER_ROW}' is currently only supported for Postgres."
)
cluster_file = os.path.join(out_dir, f"{instance_name}.cluster.backup.sql")
cluster_file = str(out_dir / f"{instance_name}{CLUSTER_SUFFIX}")
fallback_pg_dumpall(container, user, password, cluster_file)
produced = True
continue
db_name = db_value
dump_file = os.path.join(out_dir, f"{db_name}.backup.sql")
dump_file = str(out_dir / f"{db_name}{DUMP_SUFFIX}")
if db_type == "mariadb":
# Force TCP so auth matches '<user>'@'%' instead of socket -> 'localhost'.
@@ -136,13 +138,13 @@ def backup_database(
env={"PGPASSWORD": password},
)
produced = True
except BackupException as e:
raise BackupException(
except BackupError as e:
raise BackupError(
f"Postgres dump failed for instance '{instance_name}', "
f"database '{db_name}'. This database was explicitly configured "
"and therefore must succeed.\n"
f"{e}"
)
) from e
continue
return produced

11
src/baudolo/backup/docker.py
View File

@@ -1,8 +1,11 @@
from __future__ import annotations
from collections.abc import Sequence
from typing import TYPE_CHECKING
from .shell import BackupException, execute_shell_command
from .shell import BackupError, execute_shell_command
if TYPE_CHECKING:
from collections.abc import Sequence
def docker_exec_argv(
@@ -34,7 +37,7 @@ def has_tool(container: str, tool: str) -> bool:
"""
try:
execute_shell_command(docker_exec_argv(container, [tool, "--version"]))
except BackupException:
except BackupError:
return False
return True
@@ -74,7 +77,7 @@ def is_swarm_task(container: str) -> bool:
container,
]
)
except BackupException:
except BackupError:
still_listed = execute_shell_command(
[
"docker",

57
src/baudolo/backup/dumps.py
View File

@@ -3,8 +3,9 @@
from __future__ import annotations
import sys
from typing import NamedTuple
import pandas
import pandas as pd
from pandas.errors import EmptyDataError
from baudolo.databases import COLUMNS, DELIMITER
@@ -21,6 +22,19 @@ DUMP_TOOLS: tuple[tuple[str, str], ...] = (
_ENGINE_BY_IMAGE: dict[str, tuple[str, str] | None] = {}
class VolumeOutcome(NamedTuple):
"""What a dump attempt established about one volume.
``database`` says a container serving the volume speaks an engine this
tool can dump; ``dumped`` says a dump was actually written. ``engine`` is
the engine that was detected, or None when none was.
"""
database: bool
dumped: bool
engine: str | None = None
def container_engine(container: str) -> tuple[str, str] | None:
"""The (engine, dump tool) a container can serve, or None for neither.
@@ -55,15 +69,13 @@ def backup_mariadb_or_postgres(
*,
container: str,
volume_dir: str,
databases_df: pandas.DataFrame,
databases_df: pd.DataFrame,
database_containers: list[str],
) -> tuple[bool, bool]:
"""
Returns (is_db_container, dumped_any)
"""
) -> VolumeOutcome:
"""What this container contributes to its volume's outcome."""
engine = container_engine(container)
if engine is None:
return False, False
return VolumeOutcome(database=False, dumped=False)
db_type, dump_tool = engine
dumped = backup_database(
container=container,
@@ -73,20 +85,20 @@ def backup_mariadb_or_postgres(
databases_df=databases_df,
database_containers=database_containers,
)
return True, dumped
return VolumeOutcome(database=True, dumped=dumped, engine=db_type)
def _empty_databases_df() -> pandas.DataFrame:
def _empty_databases_df() -> pd.DataFrame:
"""
Create an empty DataFrame with the expected schema for databases.csv.
This allows the backup to continue without DB dumps when the CSV is missing
or empty (pandas EmptyDataError).
"""
return pandas.DataFrame(columns=list(COLUMNS))
return pd.DataFrame(columns=list(COLUMNS))
def load_databases_df(csv_path: str) -> pandas.DataFrame:
def load_databases_df(csv_path: str) -> pd.DataFrame:
"""
Load databases.csv robustly.
@@ -95,9 +107,7 @@ def load_databases_df(csv_path: str) -> pandas.DataFrame:
- Valid CSV -> return dataframe
"""
try:
return pandas.read_csv(
csv_path, sep=DELIMITER, keep_default_na=False, dtype=str
)
return pd.read_csv(csv_path, sep=DELIMITER, keep_default_na=False, dtype=str)
except FileNotFoundError:
print(
f"WARNING: databases.csv not found: {csv_path}. Continuing without database dumps.",
@@ -118,25 +128,26 @@ def backup_dumps_for_volume(
*,
containers: list[str],
vol_dir: str,
databases_df: pandas.DataFrame,
databases_df: pd.DataFrame,
database_containers: list[str],
) -> tuple[bool, bool]:
"""
Returns (found_db_container, dumped_any)
"""
) -> VolumeOutcome:
"""The volume's outcome across every container that mounts it."""
found_db = False
dumped_any = False
engine: str | None = None
for c in containers:
is_db, dumped = backup_mariadb_or_postgres(
outcome = backup_mariadb_or_postgres(
container=c,
volume_dir=vol_dir,
databases_df=databases_df,
database_containers=database_containers,
)
if is_db:
if outcome.database:
found_db = True
if dumped:
if outcome.dumped:
dumped_any = True
if engine is None:
engine = outcome.engine
return found_db, dumped_any
return VolumeOutcome(database=found_db, dumped=dumped_any, engine=engine)

35
src/baudolo/backup/layout.py
View File

@@ -2,12 +2,14 @@
from __future__ import annotations
import os
import json
import pathlib
from dirval import create_stamp_file
from .shell import BackupException, execute_shell_command
from baudolo.generation import MANIFEST_FILE, manifest_document
from .shell import BackupError, execute_shell_command
def get_machine_id() -> str:
@@ -22,11 +24,11 @@ def stamp_directory(version_dir: str) -> None:
def create_version_directory(versions_dir: str, backup_time: str) -> str:
version_dir = os.path.join(versions_dir, backup_time)
version_dir = str(pathlib.Path(versions_dir) / backup_time)
try:
pathlib.Path(version_dir).mkdir(parents=True)
except FileExistsError:
raise BackupException(
raise BackupError(
f"generation {backup_time} already exists at {version_dir}; "
"another run claimed this second - refusing to write into it, "
"since rsync --delete would overwrite that generation"
@@ -35,6 +37,25 @@ def create_version_directory(versions_dir: str, backup_time: str) -> str:
def create_volume_directory(version_dir: str, volume_name: str) -> str:
path = os.path.join(version_dir, volume_name)
pathlib.Path(path).mkdir(parents=True, exist_ok=True)
return path
path = pathlib.Path(version_dir) / volume_name
path.mkdir(parents=True, exist_ok=True)
return str(path)
def write_manifest(version_dir: str, volumes: dict[str, dict[str, bool]]) -> str:
"""Record the generation's layout and per-volume outcome.
Written before the directory is stamped, so the stamp covers it.
Args:
version_dir: the generation directory.
volumes: per volume name, ``database`` and ``dumped``.
Returns:
The path written.
"""
path = pathlib.Path(version_dir) / MANIFEST_FILE
with path.open("w", encoding="utf-8") as handle:
json.dump(manifest_document(volumes), handle, indent=2, sort_keys=True)
handle.write("\n")
return str(path)

18
src/baudolo/backup/shell.py
View File

@@ -9,10 +9,14 @@ from __future__ import annotations
import os
import subprocess
from collections.abc import Mapping, Sequence
from pathlib import Path
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from collections.abc import Mapping, Sequence
class BackupException(Exception):
class BackupError(Exception):
"""Generic exception for backup errors."""
@@ -21,7 +25,7 @@ def _child_env(env: Mapping[str, str] | None) -> dict[str, str] | None:
def _fail(command: Sequence[str], returncode: int, out: bytes, err: bytes) -> None:
raise BackupException(
raise BackupError(
f"Error in command: {' '.join(command)}\n"
f"Output: {out}\nError: {err}\n"
f"Exit code: {returncode}"
@@ -59,13 +63,13 @@ def execute_to_file(
"""
command = list(command)
print(" ".join(command), flush=True)
tmp = f"{out_file}.tmp"
with open(tmp, "wb") as handle:
tmp = Path(f"{out_file}.tmp")
with tmp.open("wb") as handle:
process = subprocess.Popen(
command, stdout=handle, stderr=subprocess.PIPE, env=_child_env(env)
)
_, err = process.communicate()
if process.returncode != 0:
os.unlink(tmp)
tmp.unlink()
_fail(command, process.returncode, b"", err)
os.replace(tmp, out_file)
tmp.replace(out_file)

32
src/baudolo/backup/snapshot.py
View File

@@ -21,11 +21,16 @@ keeps its snapshot.
from __future__ import annotations
import os
from collections.abc import Callable, Iterator
from contextlib import contextmanager
from pathlib import Path
from typing import TYPE_CHECKING
from .shell import BackupException, execute_shell_command
from .volume import Backing
from .shell import BackupError, execute_shell_command
if TYPE_CHECKING:
from collections.abc import Callable, Iterator
from .volume import Backing
KINDS = ("btrfs", "zfs")
@@ -36,10 +41,15 @@ class SnapshotError(RuntimeError):
def _resolver(subject: str, root: str) -> Callable[[str], str]:
def resolve(path: str) -> str:
relative = os.path.relpath(os.path.abspath(path), os.path.abspath(subject))
# Exception: abspath, not Path.resolve() - resolve() follows symlinks,
# which would let a symlinked volume test as inside the subject.
relative = os.path.relpath(
os.path.abspath(path), # noqa: PTH100
os.path.abspath(subject), # noqa: PTH100
)
if relative.startswith(".."):
raise SnapshotError(f"{path} lies outside the snapshot subject {subject}")
resolved = root if relative == "." else os.path.join(root, relative)
resolved = root if relative == "." else str(Path(root) / relative)
# abspath drops a trailing separator, and rsync reads "dir/" as its
# contents where "dir" means the directory itself.
@@ -54,7 +64,7 @@ def _btrfs(
# The snapshot goes inside the subject, never beside it: the kernel rejects
# a snapshot whose destination is on another filesystem, which is exactly
# what the parent directory is when the subject is a mountpoint of its own.
target = os.path.join(os.path.abspath(subject), f".{name}")
target = str(Path(os.path.abspath(subject)) / f".{name}") # noqa: PTH100 - see _resolver
run(["btrfs", "subvolume", "snapshot", "-r", subject, target])
return target, ["btrfs", "subvolume", "delete", target]
@@ -67,7 +77,7 @@ def _zfs(
if not dataset:
raise SnapshotError(f"no zfs dataset is mounted at {subject}")
run(["zfs", "snapshot", f"{dataset}@{name}"])
root = os.path.join(subject, ".zfs", "snapshot", name)
root = str(Path(subject) / ".zfs" / "snapshot" / name)
return root, ["zfs", "destroy", f"{dataset}@{name}"]
@@ -99,7 +109,9 @@ def unsnapshotted(backing: Backing, subject: str) -> str | None:
if os.path.ismount(real):
return f"its mountpoint {backing.mountpoint} sits on its own mount"
try:
crosses = os.stat(real).st_dev != os.stat(os.path.realpath(subject)).st_dev
crosses = (
Path(real).stat().st_dev != Path(os.path.realpath(subject)).stat().st_dev
)
except OSError as error:
return f"its mountpoint {backing.mountpoint} could not be read: {error}"
if crosses:
@@ -123,7 +135,7 @@ def snapshot_source(
source = resolve(backing.source)
except SnapshotError as error:
return None, str(error)
if not os.path.isdir(source):
if not Path(source).is_dir():
return None, "it was created after the snapshot was taken"
return source, ""
@@ -159,6 +171,6 @@ def volume_snapshot(
finally:
try:
run(remove)
except BackupException as error:
except BackupError as error:
# Raising here would also mask whatever the body raised.
print(f"WARNING: {root} could not be removed: {error}", flush=True)

12
src/baudolo/backup/volume.py
View File

@@ -5,7 +5,9 @@ import os
import pathlib
from dataclasses import dataclass, field
from .shell import BackupException, execute_shell_command
from baudolo.generation import FILES_DIR
from .shell import BackupError, execute_shell_command
@dataclass(frozen=True)
@@ -45,8 +47,8 @@ def get_last_backup_dir(
) -> str | None:
versions = sorted(os.listdir(versions_dir), reverse=True)
for version in versions:
candidate = os.path.join(versions_dir, version, volume_name, "files", "")
if candidate != current_backup_dir and os.path.isdir(candidate):
candidate = f"{pathlib.Path(versions_dir) / version / volume_name / FILES_DIR}/"
if candidate != current_backup_dir and pathlib.Path(candidate).is_dir():
return candidate
return None
@@ -69,7 +71,7 @@ def backup_volume(
source: directory to read from - the volume's mountpoint, or its path
inside a snapshot.
"""
dest = os.path.join(volume_dir, "files") + "/"
dest = f"{pathlib.Path(volume_dir) / FILES_DIR}/"
pathlib.Path(dest).mkdir(parents=True, exist_ok=True)
last = get_last_backup_dir(versions_dir, volume_name, dest)
@@ -82,7 +84,7 @@ def backup_volume(
try:
execute_shell_command(cmd)
except BackupException as e:
except BackupError as e:
if "file has vanished" in str(e):
print(
"Warning: Some files vanished before transfer. Continuing.", flush=True