Add cached image quickstart

bot_bottle/image_cache.py

@@ -0,0 +1,38 @@
+"""Shared helpers for cached-image quickstart warnings."""
+
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from pathlib import Path
+
+try:
+    from .config_store import ConfigStore
+    from .log import warn
+except ImportError:
+    from config_store import ConfigStore  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+    from log import warn  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+
+
+def warn_if_stale(label: str, created_at: datetime) -> None:
+    threshold_days = ConfigStore().cached_image_stale_warning_days()
+    if threshold_days < 0:
+        return
+    now = datetime.now(timezone.utc)
+    created = created_at.astimezone(timezone.utc)
+    age = now - created
+    if age.total_seconds() <= threshold_days * 86400:
+        return
+    warn(
+        f"cached {label} is {age.days} day(s) old; "
+        "quickstart does not verify it matches the current Dockerfile/context"
+    )
+
+
+def warn_if_stale_path(label: str, path: Path) -> None:
+    warn_if_stale(
+        label,
+        datetime.fromtimestamp(path.stat().st_mtime, tz=timezone.utc),
+    )
+
+
+__all__ = ["warn_if_stale", "warn_if_stale_path"]