[CI] Automatically garbage collect old docker images (GPUOpen-Drivers…

…#1885)

Run the gc script in the nightly AMDVLK wokflow, but only in the
'+clang' configuration. This is so that we do not have multiple workers
trying to delete the same images. We also expect the '+clang'
configuration to be the most robust so that it gets to the end of the
workflow consistently.

Update the gc script to be compatible with python 3.8, which is
installed by default on ubuntu 20.04.

.github/workflows/build-amdvlk-docker.yml

@@ -63,3 +63,7 @@ jobs:
       - name: Push the new image
         run: |
           docker push "$IMAGE_TAG"
+      - name: Garbage collect old docker images
+        if: matrix.feature-set == '+clang'
+        run: |
+          python3 script/gc-amdvlk-docker-images.py

script/gc-amdvlk-docker-images.py

@@ -1,7 +1,7 @@
 #! /usr/bin/env python3
 """Script to garbage collect old amdvlk docker images created by the public CI on GitHub.
 
-Requires python 3.9 or later.
+Requires python 3.8 or later.
 """
 
 import argparse
@@ -11,9 +11,9 @@
 import sys
 
 from collections import defaultdict
-from typing import Any, Optional
+from typing import Any, Dict, List, Optional, Tuple
 
-def _run_cmd(cmd: list[str]) -> tuple[bool, str]:
+def _run_cmd(cmd: List[str]) -> Tuple[bool, str]:
     """
     Runs a shell command capturing its output.
 
@@ -31,7 +31,7 @@ def _run_cmd(cmd: list[str]) -> tuple[bool, str]:
     return True, result.stdout
 
 
-def query_images(artifact_repository_url: str) -> Optional[list[dict[str, Any]]]:
+def query_images(artifact_repository_url: str) -> Optional[List[Dict[str, Any]]]:
     """
     Returns a list of JSON objects representing docker images found under
     |artifact_repository_url|, or None on error.
@@ -52,7 +52,7 @@ def query_images(artifact_repository_url: str) -> Optional[list[dict[str, Any]]]
     return list(json.loads(text))
 
 
-def find_images_to_gc(images: list[dict[str, Any]], num_last_to_keep) -> list[dict[str, Any]]:
+def find_images_to_gc(images: List[Dict[str, Any]], num_last_to_keep) -> List[Dict[str, Any]]:
     """
     Returns a subset of |images| that should be garbage collected. Preserves tagged
     images and also the most recent |num_last_to_keep| for each package.
@@ -72,7 +72,7 @@ def find_images_to_gc(images: list[dict[str, Any]], num_last_to_keep) -> list[di
     return to_gc
 
 
-def delete_images(images: list[dict[str, Any]], dry_run: bool) -> None:
+def delete_images(images: List[Dict[str, Any]], dry_run: bool) -> None:
     """
     Deletes all |images| from the repository. When |dry_run| is True, synthesizes the delete
     commands and logs but does not execute them.