CI: Make update-repos more resilient to network issues

The update-repos script currently exits immediately if one of the
underlying Git commands fails (e.g. because of a network issue). If the
repo already exists, then catch this error inside the loop and
carrying on attempting to update other repos, as the network error may
be upstream.

KAS_REPO_REF_DIR is ultimately an optimization and subsequent build
stages should be able to continue if one of the updates fail. Therefore,
ensure the script returns a special error code if at least of the Git
commands fail, and use this to set the allow_failure property of the
job.

If a repo does not exist, fail immediately as before.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

.gitlab-ci.yml

@@ -77,6 +77,8 @@ stages:
 update-repos:
   extends: .setup
   stage: prep
+  allow_failure:
+    exit_codes: 128
   script:
     - |
       flock --verbose --timeout 60 $KAS_REPO_REF_DIR ./ci/update-repos

ci/update-repos

@@ -32,6 +32,7 @@ if __name__ == "__main__":
         sys.exit(1)
 
     base_repodir = pathlib.Path(os.environ["KAS_REPO_REF_DIR"])
+    failed = False
 
     for repo in repositories:
         repodir = base_repodir / repo_shortname(repo)
@@ -41,8 +42,15 @@ if __name__ == "__main__":
             shutil.rmtree(repodir, ignore_errors=True)
 
         if repodir.exists():
-            print("Updating %s..." % repo)
+            try:
-            subprocess.run(["git", "-C", repodir, "-c", "gc.autoDetach=false", "fetch"], check=True)
+                print("Updating %s..." % repo)
+                subprocess.run(["git", "-C", repodir, "-c", "gc.autoDetach=false", "fetch"], check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                failed = True
         else:
             print("Cloning %s..." % repo)
             subprocess.run(["git", "clone", "--bare", repo, repodir], check=True)
+
+    if failed:
+        sys.exit(128)