ops(web): bound immutable release history

vehicle-data-platform/deploy/prune-release-history.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+
+from __future__ import print_function
+
+import argparse
+import os
+import shutil
+from pathlib import Path
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Keep a bounded number of immutable platform releases.')
+    parser.add_argument('root')
+    parser.add_argument('limit', type=int)
+    parser.add_argument('protected', nargs='*')
+    args = parser.parse_args()
+
+    root = Path(args.root).resolve()
+    releases = (root / 'releases').resolve()
+    if root == Path('/') or releases.parent != root or not releases.is_dir():
+        raise SystemExit('unsafe or missing release root: {}'.format(releases))
+    if args.limit < 2:
+        raise SystemExit('release history limit must be at least 2')
+
+    protected = set()
+    for value in args.protected:
+        path = Path(value).resolve()
+        if path.parent != releases or not path.is_dir():
+            raise SystemExit('protected release is outside the release root: {}'.format(path))
+        protected.add(path)
+
+    candidates = [path.resolve() for path in releases.iterdir() if path.is_dir() and not path.is_symlink()]
+    candidates.sort(key=lambda path: path.stat().st_mtime, reverse=True)
+    keep = set(protected)
+    for path in candidates:
+        if len(keep) >= args.limit:
+            break
+        keep.add(path)
+
+    removed = 0
+    for path in candidates:
+        if path in keep:
+            continue
+        if path.parent != releases:
+            raise SystemExit('refusing to remove a nested or escaped path: {}'.format(path))
+        shutil.rmtree(str(path))
+        removed += 1
+
+    print('release_prune=ok before={} kept={} removed={}'.format(len(candidates), len(keep), removed))
+
+
+if __name__ == '__main__':
+    main()