Clean up local buildah images and manifests after push:

Use a temporary local manifest name to avoid collisions on repeated
publishes, and remove local manifests and intermediate images in a
finally block after push completes.

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>

Author: jacobweinstock

captain/buildah.py

@@ -162,3 +162,14 @@ def manifest_push(
     _log = logger or _default_log
     _log.log(f"buildah manifest push → {dest}")
     run(["buildah", "manifest", "push", "--all", manifest, f"docker://{dest}"])
+
+
+def rmi(
+    image: str,
+    *,
+    logger: StageLogger | None = None,
+) -> None:
+    """Remove a local image or manifest list."""
+    _log = logger or _default_log
+    _log.log(f"buildah rmi {image}")
+    run(["buildah", "rmi", image])

captain/oci.py

@@ -33,6 +33,7 @@
 import tarfile
 from datetime import datetime, timezone
 from pathlib import Path
+from uuid import uuid4
 
 from captain import artifacts, buildah, skopeo
 from captain.config import Config
@@ -206,6 +207,37 @@ def _build_platform_image(
     return current
 
 
+def _create_push_cleanup(
+    image_ids: list[str],
+    dest_ref: str,
+    logger: StageLogger,
+) -> None:
+    """Create a manifest list from *image_ids*, push it to *dest_ref*, and clean up.
+
+    Uses a temporary local manifest name to avoid collisions on repeated
+    publishes.  After a successful (or failed) push, the local manifest
+    and all *image_ids* are removed on a best-effort basis.
+    """
+    temp_name = f"captain-local-{uuid4().hex[:12]}"
+    manifest_id: str | None = None
+    try:
+        manifest_id = buildah.manifest_create(temp_name, logger=logger)
+        for image_id in image_ids:
+            buildah.manifest_add(manifest_id, image_id, logger=logger)
+        buildah.manifest_push(manifest_id, dest_ref, logger=logger)
+    finally:
+        if manifest_id is not None:
+            try:
+                buildah.rmi(manifest_id, logger=logger)
+            except Exception:
+                pass
+        for image_id in image_ids:
+            try:
+                buildah.rmi(image_id, logger=logger)
+            except Exception:
+                pass
+
+
 def _publish_single_arch(
     *,
     layer_tars: list[Path],
@@ -236,10 +268,7 @@ def _publish_single_arch(
         )
         image_ids.append(image_id)
 
-    manifest_id = buildah.manifest_create(ref, logger=logger)
-    for image_id in image_ids:
-        buildah.manifest_add(manifest_id, image_id, logger=logger)
-    buildah.manifest_push(manifest_id, ref, logger=logger)
+    _create_push_cleanup(image_ids, ref, logger)
 
 
 def _publish_combined(
@@ -314,10 +343,7 @@ def _publish_combined(
         )
         image_ids.append(image_id)
 
-    manifest_id = buildah.manifest_create(combined_ref, logger=logger)
-    for image_id in image_ids:
-        buildah.manifest_add(manifest_id, image_id, logger=logger)
-    buildah.manifest_push(manifest_id, combined_ref, logger=logger)
+    _create_push_cleanup(image_ids, combined_ref, logger)
     return True