Add Gitea build, container tests and registry publication

ci/main-head.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+"""Read the current main head without placing an access token in arguments/logs."""
+import json
+import os
+import sys
+import urllib.error
+import urllib.request
+
+url = os.environ['GITEA_SERVER_URL'].rstrip('/') + '/api/v1/repos/' + os.environ['CI_REPOSITORY'] + '/branches/main'
+request = urllib.request.Request(url, headers={'Authorization': 'token ' + os.environ['REGISTRY_TOKEN']})
+try:
+    with urllib.request.urlopen(request, timeout=30) as response:
+        print(json.load(response)['commit']['id'])
+except (urllib.error.URLError, KeyError, ValueError) as error:
+    print(f'Cannot verify current main head ({type(error).__name__})', file=sys.stderr)
+    sys.exit(1)