ecr_gc: Iterate through all tags, reduce prints (#42492)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42492

There's a potential for multiple tags to be created for the same digest
so we should iterate through all potential tags so that we're not
deleting digests that are associated with tags that we actually want.

Also, reduced the number of prints in this script to only the absolutely
necessary prints. (i.e. only the deleted images)

Signed-off-by: Eli Uriegas <eliuriegas@fb.com>

Test Plan: Imported from OSS

Reviewed By: ezyang

Differential Revision: D22909248

Pulled By: seemethere

fbshipit-source-id: 7f2e540d133485ed6464e413b01ef67aa73df432

.circleci/ecr_gc_docker/gc.py

@@ -88,6 +88,9 @@ parser = argparse.ArgumentParser(description="Delete old Docker tags from regist
 parser.add_argument(
     "--dry-run", action="store_true", help="Dry run; print tags that would be deleted"
 )
+parser.add_argument(
+    "--debug", action="store_true", help="Debug, print ignored / saved tags"
+)
 parser.add_argument(
     "--keep-stable-days",
     type=int,
@@ -164,51 +167,48 @@ for repo in repos(client):
 
     # Keep list of image digests to delete for this repository
     digest_to_delete = []
-    print(repositoryName)
 
     for image in images(client, repo):
         tags = image.get("imageTags")
         if not isinstance(tags, (list,)) or len(tags) == 0:
             continue
-
-        tag = tags[0]
         created = image["imagePushedAt"]
         age = now - created
-        if any([
-                looks_like_git_sha(tag),
-                tag.isdigit(),
-                tag.count("-") == 4,  # TODO: Remove, this no longer applies as tags are now built using a SHA1
-                tag in ignore_tags]):
-            window = stable_window
-            if tag in ignore_tags:
-                stable_window_tags.append((repositoryName, tag, "", age, created))
-            elif age < window:
-                stable_window_tags.append((repositoryName, tag, window, age, created))
-        else:
-            window = unstable_window
+        for tag in tags:
+            if any([
+                    looks_like_git_sha(tag),
+                    tag.isdigit(),
+                    tag.count("-") == 4,  # TODO: Remove, this no longer applies as tags are now built using a SHA1
+                    tag in ignore_tags]):
+                window = stable_window
+                if tag in ignore_tags:
+                    stable_window_tags.append((repositoryName, tag, "", age, created))
+                elif age < window:
+                    stable_window_tags.append((repositoryName, tag, window, age, created))
+            else:
+                window = unstable_window
 
-        if tag in ignore_tags:
-            print("Ignoring tag {}:{} (age: {})".format(repositoryName, tag, age))
-            continue
-        if age < window:
-            print("Not deleting manifest for tag {}:{} (age: {})".format(repositoryName, tag, age))
-            continue
-
-        if args.dry_run:
-            print("(dry run) Deleting manifest for tag {}:{} (age: {})".format(repositoryName, tag, age))
+            if tag in ignore_tags or age < window:
+                if args.debug:
+                    print("Ignoring {}:{} (age: {})".format(repositoryName, tag, age))
+                break
         else:
-            print("Deleting manifest for tag{}:{} (age: {})".format(repositoryName, tag, age))
+            for tag in tags:
+                print("{}Deleting {}:{} (age: {})".format("(dry run) " if args.dry_run else "", repositoryName, tag, age))
             digest_to_delete.append(image["imageDigest"])
+    if args.dry_run:
+        if args.debug:
+            print("Skipping actual deletion, moving on...")
+    else:
+        # Issue batch delete for all images to delete for this repository
+        # Note that as of 2018-07-25, the maximum number of images you can
+        # delete in a single batch is 100, so chunk our list into batches of
+        # 100
+        for c in chunks(digest_to_delete, 100):
+            client.batch_delete_image(
+                registryId="308535385114",
+                repositoryName=repositoryName,
+                imageIds=[{"imageDigest": digest} for digest in c],
+            )
 
-    # Issue batch delete for all images to delete for this repository
-    # Note that as of 2018-07-25, the maximum number of images you can
-    # delete in a single batch is 100, so chunk our list into batches of
-    # 100
-    for c in chunks(digest_to_delete, 100):
-        client.batch_delete_image(
-            registryId="308535385114",
-            repositoryName=repositoryName,
-            imageIds=[{"imageDigest": digest} for digest in c],
-        )
-
-    save_to_s3(args.filter_prefix, stable_window_tags)
+        save_to_s3(args.filter_prefix, stable_window_tags)