Restore detailed backup mail reports with bounded local delivery

lib/report.py

@@ -0,0 +1,136 @@
+#!/usr/bin/env python3
+"""Build private UTF-8 backup reports; never read executable config/credentials.
+
+Sizes are captured before staging cleanup. Delivery uses only the local MTA and
+has a timeout; a reporting failure never turns a failed backup into a success.
+"""
+import argparse
+from collections import deque
+import datetime as dt
+from email.message import EmailMessage
+from email.policy import SMTP
+import json
+import os
+from pathlib import Path
+import socket
+import subprocess
+import sys
+import time
+
+
+def allocated(path):
+    """Report disk allocation, like du in the old report, without following links."""
+    result = subprocess.run(['du', '-s', '-B1', '--', str(path)],
+                            capture_output=True, text=True, timeout=30, check=True)
+    return int(result.stdout.split()[0])
+
+
+def snapshot(output, staging, archives):
+    data = {'staged': {}, 'archives': {}}
+    if staging and Path(staging).is_dir():
+        root = Path(staging)
+        # Measure components independently; the total accounts for shared links.
+        paths = sorted((root/'files').glob('*')) + [root/'db', root/'meta']
+        for path in paths:
+            if path.exists():
+                data['staged'][path.name] = allocated(path)
+        data['staging_total'] = allocated(root)
+    if archives and Path(archives).is_dir():
+        for path in sorted(Path(archives).glob('*.tar.*')):
+            if path.is_file() and not path.is_symlink():
+                data['archives'][path.name] = path.stat().st_size
+    Path(output).write_text(json.dumps(data), encoding='utf-8')
+
+
+def human(value):
+    for unit in ('B', 'KiB', 'MiB', 'GiB', 'TiB'):
+        if value < 1024 or unit == 'TiB':
+            return f'{value:.1f} {unit}'
+        value /= 1024
+
+
+def deliver(args):
+    host = socket.getfqdn()
+    now = dt.datetime.now().astimezone()
+    state = 'SUCCESS' if args.exit_code == 0 else 'FAIL'
+    try:
+        sizes = json.loads(Path(args.sizes).read_text())
+    except (OSError, ValueError):
+        sizes = {}
+    # Bounded memory even for long-running rclone logs. Tail length is configurable.
+    with open(args.log, encoding='utf-8', errors='replace') as stream:
+        tail = ''.join(deque(stream, maxlen=args.tail_lines))
+    upload = {'NOT_STARTED': 'Nicht gestartet', 'DISABLED': 'Deaktiviert (nur lokal)',
+              'COPY': 'Nicht abgeschlossen: Upload', 'CHECK': 'Nicht abgeschlossen: Rückleseprüfung',
+              'MARKER': 'Nicht abgeschlossen: Abschlussmarker',
+              'VERIFIED': 'OK (Inhalt und Abschlussmarker zurückgelesen)'}[args.upload_status]
+    body = [
+        'Backup Report', '=============', f'Zeit: {now.isoformat(timespec="seconds")}',
+        f'Host: {host}', f'Status: {state}', f'Exit code: {args.exit_code}',
+        f'Dauer: {max(0, int(time.time()) - args.started)}s', f'Lauf: {args.run}',
+        f'Letzte Phase: {args.phase}', '', f'Config: {args.config}', f'Log: {args.log}',
+        f'Workdir: {args.workdir}', f'Archive dir: {args.archive_dir}',
+        f'Kompression: {args.compression}', '', 'Remote', '------',
+        f'Upload: {str(args.upload_status != "DISABLED").lower()}',
+        f'Remote base: {args.remote or "nicht konfiguriert"}', f'Upload Status: {upload}',
+        'Die separate Update-Abnahme steht in result.txt; dies ist der Backup-Bericht.',
+        '', 'Größen', '------', 'Staging: belegter Speicher vor Bereinigung; Archive: Dateigrößen.',
+    ]
+    for label, value in sizes.get('staged', {}).items():
+        body.append(f'{label} staged: {human(value)}')
+    body.append('Staging total: '+(human(sizes['staging_total']) if 'staging_total' in sizes else 'nicht verfügbar'))
+    body.extend(['', 'Archive', '-------'])
+    for name, value in sizes.get('archives', {}).items():
+        body.append(f'{name}: {human(value)} ({value} Bytes)')
+    if not sizes.get('archives'):
+        body.append('Keine Archive erfasst.')
+    else:
+        body.append('Archive total: '+human(sum(sizes['archives'].values())))
+    body.extend(['', f'Log-Auszug (letzte {args.tail_lines} Zeilen)', '-----------------', tail])
+    message = EmailMessage(policy=SMTP)
+    # EmailMessage rejects CR/LF in headers and encodes non-ASCII safely.
+    sender = args.sender or f'app-backup@{host}'
+    if not args.to.strip() or not sender.strip():
+        raise ValueError('Mail recipient and sender must not be empty')
+    message['From'] = sender
+    message['To'] = args.to
+    message['Subject'] = f'{args.subject_prefix} {state} {host} {args.run}'
+    message['Date'] = now
+    message.set_content('\n'.join(body), charset='utf-8')
+    raw = message.as_bytes()
+    Path(args.output).write_bytes(raw)
+    # -oi prevents a single dot in a log line from terminating the message.
+    # Headers supply recipients; no shell or SMTP credentials are involved.
+    subprocess.run([args.sendmail, '-oi', '-t'], input=raw, check=True, timeout=args.timeout)
+    print(f'Mail report handed to local MTA: {args.output}')
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    commands = parser.add_subparsers(dest='command', required=True)
+    snap = commands.add_parser('snapshot')
+    for name in ('output', 'staging', 'archives'):
+        snap.add_argument(name)
+    mail = commands.add_parser('deliver')
+    for name in ('sizes', 'log', 'output', 'to', 'sender', 'subject-prefix', 'run', 'phase',
+                 'upload-status', 'config', 'workdir', 'archive-dir', 'compression', 'remote', 'sendmail'):
+        mail.add_argument('--'+name, required=True)
+    for name in ('exit-code', 'started', 'tail-lines', 'timeout'):
+        mail.add_argument('--'+name, type=int, required=True)
+    args = parser.parse_args()
+    if args.command == 'snapshot':
+        snapshot(args.output, args.staging, args.archives)
+    else:
+        if not 0 <= args.tail_lines <= 10000 or not 1 <= args.timeout <= 300:
+            raise ValueError('Invalid mail tail length or timeout')
+        deliver(args)
+
+
+if __name__ == '__main__':
+    os.umask(0o077)
+    try:
+        main()
+    except Exception as exc:
+        # Do not echo header values or MTA arguments which might include addresses.
+        print(f'WARNING: mail report failed ({type(exc).__name__}); inspect local report/MTA.', file=sys.stderr)
+        sys.exit(1)