Add dry run option

tools/update_required_branch_checks.py

@@ -13,16 +13,31 @@
 # limitations under the License.
 """Updates the requires status checks for a branch."""
 
+import argparse
 from github import Github
 from typing import List
 
 YOUR_GITHUB_TOKEN = ''
 
+TARGET_REPO = 'youtube/cobalt'
+
+EXCLUDED_CHECK_PATTERNS = ['feedback/copybara', '_on_device_', r'${{']
+
 # Exclude rc_11 and COBALT_9 releases.
 MINIMUM_LTS_RELEASE_NUMBER = 19
 LATEST_LTS_RELEASE_NUMBER = 24
 
 
+def parse_args():
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--dry_run',
+      action='store_true',
+      default=False,
+      help='Only print protection updates.')
+  return parser.parse_args()
+
+
 def get_protected_branches() -> List[str]:
   branches = ['main']
   for i in range(MINIMUM_LTS_RELEASE_NUMBER, LATEST_LTS_RELEASE_NUMBER + 1):
@@ -32,23 +47,27 @@ def get_protected_branches() -> List[str]:
 
 def initialize_repo_connection():
   g = Github(YOUR_GITHUB_TOKEN)
-  return g.get_repo('youtube/cobalt')
+  return g.get_repo(TARGET_REPO)
 
 
 def get_checks_for_branch(repo, branch: str):
-  latest_open_pr = repo.get_pulls(
-      state='open', sort='updated', base=branch, direction='desc')[0]
-  latest_pr_commit = repo.get_commit(latest_open_pr.head)
+  prs = repo.get_pulls(
+      state='open', sort='updated', base=branch, direction='desc')
+  try:
+    latest_pr = prs[0]
+  except IndexError:
+    prs = repo.get_pulls(
+        state='closed', sort='updated', base=branch, direction='desc')
+    latest_pr = prs[0]
+  latest_pr_commit = repo.get_commit(latest_pr.head.sha)
   checks = latest_pr_commit.get_check_runs()
   return checks
 
 
 def should_include_run(check_run) -> bool:
-  # Filter out check runs that have '_on_device_' in the name.
-  if '_on_device_' in check_run.name:
-    return False
-  if check_run.name == 'feedback/copybara':
-    return False
+  for pattern in EXCLUDED_CHECK_PATTERNS:
+    if pattern in check_run.name:
+      return False
   return True
 
 
@@ -59,17 +78,28 @@ def get_required_checks_for_branch(repo, branch: str) -> List[str]:
   return check_names
 
 
+def print_checks(branch: str, check_names: List[str]):
+  print(f'Checks for {branch}:')
+  for check_name in check_names:
+    print(check_name)
+  print()
+
+
 def update_protection_for_branch(repo, branch: str, check_names: List[str]):
   branch = repo.get_branch(branch)
   branch.edit_protection(contexts=check_names)
 
 
 def main():
+  args = parse_args()
   branches = get_protected_branches()
   repo = initialize_repo_connection()
   for branch in branches:
     required_checks = get_required_checks_for_branch(repo, branch)
-    update_protection_for_branch(repo, branch, required_checks)
+    if args.dry_run:
+      print_checks(branch, required_checks)
+    else:
+      update_protection_for_branch(repo, branch, required_checks)
 
 
 if __name__ == '__main__':