feat(backup): add GCS offsite backup executor

Add gcs_backup_executor with git_bundle mode for backing up bare git
repos to Google Cloud Storage. Includes retention management and
bundle verification. Adds google-cloud-storage dependency and
GCS_CREDENTIALS_FILE setting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "the-scheduler"
-version = "1.1.3"
+version = "1.2.0"
 description = "System-wide maintenance orchestration - backups, doc mirroring, cleanup, task automation"
 readme = "README.md"
 requires-python = ">=3.12"
@@ -26,6 +26,8 @@ dependencies = [
     "gitpython~=3.1.43",
     # Security/Auth
     "python-jose[cryptography]~=3.3.0",
+    # Cloud storage
+    "google-cloud-storage~=2.18.0",
 ]
 
 [project.optional-dependencies]

requirements.txt

@@ -26,6 +26,9 @@ gitpython~=3.1.43       # Latest stable
 # Security/Auth
 python-jose[cryptography]~=3.3.0  # JWT handling
 
+# Cloud storage
+google-cloud-storage~=2.18.0  # GCS offsite backups
+
 # Testing
 pytest~=8.3.4              # Test framework
 pytest-asyncio~=0.25.2     # Async test support

src/config.py

@@ -66,6 +66,9 @@ class Settings(BaseSettings):
     backup_retention_weekly: int = Field(default=4, alias="BACKUP_RETENTION_WEEKLY")
     backup_retention_monthly: int = Field(default=12, alias="BACKUP_RETENTION_MONTHLY")
 
+    # Google Cloud Storage
+    gcs_credentials_file: str = Field(default="", alias="GCS_CREDENTIALS_FILE")
+
     # Documentation Mirroring
     docs_mirror_path: str = Field(default="/docs-mirror", alias="DOCS_MIRROR_PATH")
     docs_check_interval: int = Field(default=21600, alias="DOCS_CHECK_INTERVAL")  # 6 hours

src/executors/gcs_backup_executor.py

@@ -0,0 +1,199 @@
+"""
+Google Cloud Storage Backup Executor
+Backs up data to GCS buckets. Supports multiple modes:
+- git_bundle: Creates a git bundle from a bare repo and uploads it
+"""
+import asyncio
+import logging
+import time
+from datetime import datetime
+from pathlib import Path
+from typing import List, Optional
+
+from google.cloud import storage
+
+from src.config import Settings
+
+logger = logging.getLogger(__name__)
+
+
+async def execute(config: dict, settings: Settings) -> str:
+    """
+    Execute GCS backup task.
+
+    Config schema:
+        {
+            "mode": "git_bundle",
+            "bucket": "bucket-name",
+            "prefix": "gitea/settled-reach",
+            "credentials_path": "/secrets/gcs-sa-key.json",
+            "repo_path": "/data/docker-data/gitea/data/git/repositories/user/repo.git",
+            "retention_count": 7,
+            "dry_run": false
+        }
+
+    Args:
+        config: Backup configuration
+        settings: Global scheduler settings
+
+    Returns:
+        Summary of backup operation
+
+    Raises:
+        Exception: On backup failure
+    """
+    mode = config.get('mode')
+    if not mode:
+        raise ValueError("Missing required config field: mode")
+
+    if mode == 'git_bundle':
+        return await _mode_git_bundle(config, settings)
+    else:
+        raise ValueError(f"Unknown backup mode: {mode}")
+
+
+async def _mode_git_bundle(config: dict, settings: Settings) -> str:
+    """Create a git bundle from a bare repo and upload to GCS."""
+    bucket_name = config.get('bucket')
+    prefix = config.get('prefix', '').strip('/')
+    credentials_path = config.get('credentials_path', settings.gcs_credentials_file)
+    repo_path = Path(config.get('repo_path', ''))
+    retention_count = config.get('retention_count', 7)
+    dry_run = config.get('dry_run', False)
+
+    # Validate
+    if not bucket_name:
+        raise ValueError("Missing required config field: bucket")
+    if not repo_path or not str(repo_path).strip():
+        raise ValueError("Missing required config field: repo_path")
+    if not repo_path.exists():
+        raise ValueError(f"Repository path does not exist: {repo_path}")
+    if not (repo_path / 'HEAD').exists():
+        raise ValueError(f"Not a valid git repository: {repo_path}")
+
+    repo_name = repo_path.name.removesuffix('.git')
+    timestamp = datetime.now().strftime('%Y%m%d-%H%M%S')
+    bundle_filename = f"{repo_name}-{timestamp}.bundle"
+    bundle_path = Path(f"/tmp/{bundle_filename}")
+
+    logger.info(f"Starting GCS backup: mode=git_bundle, repo={repo_name}, dry_run={dry_run}")
+
+    try:
+        # Step 1: Create git bundle
+        logger.info(f"Creating git bundle from {repo_path}")
+        start = time.monotonic()
+
+        await _run_command([
+            'git', 'bundle', 'create',
+            str(bundle_path),
+            '--all'
+        ], cwd=repo_path)
+
+        bundle_duration = time.monotonic() - start
+
+        if not bundle_path.exists():
+            raise Exception("Git bundle was not created")
+
+        bundle_size = bundle_path.stat().st_size
+        bundle_size_mb = bundle_size / (1024 * 1024)
+        logger.info(f"Bundle created: {bundle_filename} ({bundle_size_mb:.1f} MB) in {bundle_duration:.1f}s")
+
+        # Step 2: Verify bundle
+        await _run_command([
+            'git', 'bundle', 'verify',
+            str(bundle_path)
+        ], cwd=repo_path)
+        logger.info("Bundle verified OK")
+
+        if dry_run:
+            return (
+                f"[DRY RUN] Would upload {bundle_filename} ({bundle_size_mb:.1f} MB) "
+                f"to gs://{bucket_name}/{prefix}/{bundle_filename}"
+            )
+
+        # Step 3: Upload to GCS
+        gcs_path = f"{prefix}/{bundle_filename}" if prefix else bundle_filename
+        logger.info(f"Uploading to gs://{bucket_name}/{gcs_path}")
+        start = time.monotonic()
+
+        client = storage.Client.from_service_account_json(credentials_path)
+        bucket = client.bucket(bucket_name)
+        blob = bucket.blob(gcs_path)
+        blob.upload_from_filename(str(bundle_path), timeout=3600)
+
+        upload_duration = time.monotonic() - start
+        logger.info(f"Upload complete in {upload_duration:.1f}s")
+
+        # Step 4: Retention cleanup in GCS
+        deleted_count = await _cleanup_gcs_retention(
+            client, bucket_name, prefix, repo_name, retention_count
+        )
+
+        return (
+            f"Backup completed: {bundle_filename} ({bundle_size_mb:.1f} MB). "
+            f"Bundle: {bundle_duration:.1f}s, Upload: {upload_duration:.1f}s. "
+            f"GCS: gs://{bucket_name}/{gcs_path}. "
+            f"Retention: {deleted_count} old bundle(s) removed."
+        )
+
+    finally:
+        # Always clean up the local temp file
+        if bundle_path.exists():
+            bundle_path.unlink()
+            logger.debug(f"Cleaned up temp file: {bundle_path}")
+
+
+async def _cleanup_gcs_retention(
+    client: storage.Client,
+    bucket_name: str,
+    prefix: str,
+    repo_name: str,
+    retention_count: int
+) -> int:
+    """Delete old bundles from GCS, keeping only the most recent retention_count."""
+    if retention_count <= 0:
+        return 0
+
+    bucket = client.bucket(bucket_name)
+    blob_prefix = f"{prefix}/{repo_name}-" if prefix else f"{repo_name}-"
+
+    blobs = list(bucket.list_blobs(prefix=blob_prefix))
+    bundle_blobs = [b for b in blobs if b.name.endswith('.bundle')]
+
+    if len(bundle_blobs) <= retention_count:
+        logger.info(f"Retention OK: {len(bundle_blobs)} bundles (limit: {retention_count})")
+        return 0
+
+    # Sort by name (timestamp in name ensures chronological order)
+    bundle_blobs.sort(key=lambda b: b.name)
+    to_delete = bundle_blobs[:-retention_count]
+
+    for blob in to_delete:
+        logger.info(f"Deleting old bundle: {blob.name}")
+        blob.delete()
+
+    logger.info(f"Retention cleanup: deleted {len(to_delete)} old bundle(s)")
+    return len(to_delete)
+
+
+async def _run_command(
+    cmd: List[str],
+    cwd: Optional[Path] = None,
+) -> str:
+    """Run shell command asynchronously."""
+    logger.debug(f"Running: {' '.join(cmd)} (cwd: {cwd})")
+
+    proc = await asyncio.create_subprocess_exec(
+        *cmd,
+        cwd=cwd,
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE
+    )
+
+    stdout, stderr = await proc.communicate()
+
+    if proc.returncode != 0:
+        error_msg = stderr.decode() if stderr else "Unknown error"
+        raise Exception(f"Command failed: {' '.join(cmd)}\n{error_msg}")
+
+    return stdout.decode()