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https://github.com/kevinveenbirkenbach/docker-volume-backup.git
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Kevin Veen-Birkenbach
94637c32aa
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>
76 lines
2.4 KiB
Python
76 lines
2.4 KiB
Python
"""Running external commands without a shell.
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Every command is an argv list. A database name, a password or a container name
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therefore cannot close a quote and start a second command, which a formatted
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string handed to ``shell=True`` allowed.
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"""
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from __future__ import annotations
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import os
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import subprocess
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from pathlib import Path
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from typing import TYPE_CHECKING
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if TYPE_CHECKING:
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from collections.abc import Mapping, Sequence
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class BackupError(Exception):
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"""Generic exception for backup errors."""
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def _child_env(env: Mapping[str, str] | None) -> dict[str, str] | None:
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return None if env is None else {**os.environ, **env}
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def _fail(command: Sequence[str], returncode: int, out: bytes, err: bytes) -> None:
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raise BackupError(
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f"Error in command: {' '.join(command)}\n"
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f"Output: {out}\nError: {err}\n"
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f"Exit code: {returncode}"
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)
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def execute_shell_command(
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command: Sequence[str], *, env: Mapping[str, str] | None = None
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) -> list[str]:
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"""Run *command* and return its stdout lines.
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Args:
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command: argv, the program first.
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env: variables added to the child's environment, for values that must
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not appear in the argv of a process listing.
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"""
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command = list(command)
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print(" ".join(command), flush=True)
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process = subprocess.Popen(
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command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=_child_env(env)
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)
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out, err = process.communicate()
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if process.returncode != 0:
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_fail(command, process.returncode, out, err)
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return [line.decode("utf-8") for line in out.splitlines()]
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def execute_to_file(
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command: Sequence[str], out_file: str, *, env: Mapping[str, str] | None = None
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) -> None:
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"""Run *command*, writing its stdout to *out_file* only once it succeeded.
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The output goes to a sibling temporary file first, so a partial or empty
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stream from a failing dump never takes the place of a valid backup.
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"""
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command = list(command)
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print(" ".join(command), flush=True)
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tmp = Path(f"{out_file}.tmp")
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with tmp.open("wb") as handle:
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process = subprocess.Popen(
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command, stdout=handle, stderr=subprocess.PIPE, env=_child_env(env)
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)
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_, err = process.communicate()
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if process.returncode != 0:
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tmp.unlink()
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_fail(command, process.returncode, b"", err)
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tmp.replace(out_file)
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