mirror of
https://github.com/kevinveenbirkenbach/docker-volume-backup.git
synced 2026-08-01 12:34:50 +00:00
Kevin Veen-Birkenbach
d4317827bd
Backing up a live volume with rsync copies a moving target: a database
written to mid-copy lands on disk in a state no engine ever committed.
Stopping the container avoids that at the cost of downtime.
A snapshot removes both. `--snapshot {btrfs,zfs}` with `--snapshot-subject`
freezes the docker root once per run, and every volume copy is then read
from that frozen tree while the containers keep serving. A restore of such
a copy is an ordinary crash recovery, which every supported engine performs
on its own at startup.
An unsupported filesystem or an unknown snapshot kind fails loudly rather
than degrading to a live copy, since a silent fallback would return exactly
the torn backup the mode exists to prevent. `--shutdown` is rejected
alongside `--snapshot` instead of being ignored: under a snapshot no
container is ever stopped, so accepting the flag would promise downtime
semantics the run does not deliver.
Copies out of a snapshot skip rsync's --checksum verification. The source
is immutable for the lifetime of the copy, so size-and-mtime cannot race,
and dropping the second full read roughly halves the I/O per volume.
backup/app.py grew past what one module could carry and is split into
layout, policy and dumps along the lines it already had internally.
Tests: unit coverage for the new snapshot, layout, policy, volume and cli
units; e2e cases drive real btrfs, zfs and ext4 filesystems on loop devices
in a privileged container, including a MariaDB that is written to across
the snapshot and must recover from the restored copy without losing a
committed row. CI installs zfs and sets E2E_REQUIRE_FILESYSTEMS so a
missing kernel module fails the build instead of silently skipping a
filesystem.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
115 lines
3.4 KiB
Python
115 lines
3.4 KiB
Python
"""Fixtures and paths the e2e suite builds its scenarios from."""
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from __future__ import annotations
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import shutil
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import subprocess
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from pathlib import Path
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from .process import machine_hash, run
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# postgres 18+ mounts at /var/lib/postgresql, not /var/lib/postgresql/data.
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POSTGRES_IMAGE = "postgres:alpine"
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POSTGRES_DATA_DIR = "/var/lib/postgresql"
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MARIADB_IMAGE = "mariadb:latest"
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MARIADB_DATA_DIR = "/var/lib/mysql"
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def backup_run(
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*,
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backups_dir: str,
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repo_name: str,
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compose_dir: str,
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databases_csv: str,
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database_containers: list[str],
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images_no_stop_required: list[str],
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images_no_backup_required: list[str] | None = None,
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dump_only_sql: bool = False,
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) -> None:
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cmd = [
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"baudolo",
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"--compose-dir",
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compose_dir,
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"--hard-restart-projects",
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"mailu",
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"--repo-name",
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repo_name,
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"--databases-csv",
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databases_csv,
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"--backups-dir",
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backups_dir,
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"--database-containers",
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*database_containers,
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"--images-no-stop-required",
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*images_no_stop_required,
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]
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if images_no_backup_required:
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cmd += ["--images-no-backup-required", *images_no_backup_required]
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if dump_only_sql:
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cmd += ["--dump-only-sql"]
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try:
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run(cmd, capture=True, check=True)
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except subprocess.CalledProcessError as e:
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print(">>> baudolo failed (exit code:", e.returncode, ")")
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if e.stdout:
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print(">>> baudolo STDOUT:\n" + e.stdout)
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if e.stderr:
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print(">>> baudolo STDERR:\n" + e.stderr)
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raise
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def latest_version_dir(backups_dir: str, repo_name: str) -> tuple[str, str]:
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"""
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Returns (hash, version) for the latest backup.
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"""
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h = machine_hash()
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root = Path(backups_dir) / h / repo_name
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if not root.is_dir():
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raise FileNotFoundError(str(root))
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versions = sorted([p.name for p in root.iterdir() if p.is_dir()])
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if not versions:
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raise RuntimeError(f"No versions found under {root}")
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return h, versions[-1]
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def backup_path(backups_dir: str, repo_name: str, version: str, volume: str) -> Path:
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h = machine_hash()
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return Path(backups_dir) / h / repo_name / version / volume
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def create_minimal_compose_dir(base: str) -> str:
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"""
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baudolo requires --compose-dir. Create an empty dir with one non-compose subdir.
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"""
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p = Path(base) / "compose-root"
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p.mkdir(parents=True, exist_ok=True)
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(p / "noop").mkdir(parents=True, exist_ok=True)
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return str(p)
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def write_databases_csv(path: str, rows: list[tuple[str, str, str, str]]) -> None:
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"""
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rows: (instance, database, username, password)
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database may be '' (empty) to trigger pg_dumpall behavior if you want, but here we use db name.
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"""
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Path(path).parent.mkdir(parents=True, exist_ok=True)
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with open(path, "w", encoding="utf-8") as f:
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f.write("instance;database;username;password\n")
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for inst, db, user, pw in rows:
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f.write(f"{inst};{db};{user};{pw}\n")
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def cleanup_docker(*, containers: list[str], volumes: list[str]) -> None:
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for c in containers:
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run(["docker", "rm", "-f", c], capture=True, check=False)
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for v in volumes:
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run(["docker", "volume", "rm", "-f", v], capture=True, check=False)
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def ensure_empty_dir(path: str) -> None:
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p = Path(path)
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if p.exists():
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shutil.rmtree(p)
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p.mkdir(parents=True, exist_ok=True)
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