Add CI and deploy summaries

.gitea/workflows/release.py

@@ -231,6 +231,8 @@ def build(output):
             )
             signature.write_text(image + '\n')
         release = {'version': 1, 'sha': sha, 'images': {}, 'inputs': {}}
+        built = []
+        reused = []
         for name, (context, dockerfile) in IMAGES.items():
             image = f'gcr.forust.xyz/forust/{name}'
             inputs = fingerprint(context, dockerfile)
@@ -255,8 +257,10 @@ def build(output):
             if exists:
                 print(f'Reuse {name}: inputs unchanged')
                 digest = old_digest
+                reused.append((name, image, digest))
             else:
                 print(f'Build {name}', flush=True)
+                built.append((name, image))
                 metadata = Path(docker_config) / 'metadata.json'
                 command(
                     'docker',
@@ -286,6 +290,23 @@ def build(output):
             release['inputs'][image] = inputs
         validate_release(release, sha)
         output.write_text(json.dumps(release, indent=2) + '\n')
+        summary = os.environ.get('GITHUB_STEP_SUMMARY')
+        if summary:
+            lines = [f'## Image release for `{sha}`', '', '### Built']
+            lines.extend(f'- `{name}` — `{image}`' for name, image in built)
+            if not built:
+                lines.append('- None')
+            lines.extend(['', '### Reused from successful CI'])
+            lines.extend(f'- `{name}` — `{image}@{digest}`' for name, image, digest in reused)
+            if not reused:
+                lines.append('- None')
+            lines.extend(['', '### Release digests'])
+            lines.extend(
+                f'- `{name}` — `{image}@{release["images"][image]}`'
+                for name in IMAGES
+                for image in [f'gcr.forust.xyz/forust/{name}']
+            )
+            Path(summary).write_text('\n'.join(lines) + '\n')
     finally:
         # Cleanup errors must neither leak credentials nor mask the original build error.
         try: