Add release-metadata updating script (#19)

* Add release-metadata updating script

* Add some checks, accept github module's output format

Author: rell-fastly

scripts/update-release-metadata.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+import json
+import sys
+import boto3
+import re
+
+
+def fetch_metadata():
+  '''
+  Pull metadata from s3 as byte stream.
+  '''
+  client = boto3.client('s3')
+  try:
+    resp = client.get_object(
+        Bucket='release-metadata',
+        Key='release-versions'
+    )
+  except boto3.S3.Client.exceptions.NoSuchKey:
+    sys.stderr.write('No release-metadata key found.  Check permissions.\n')
+    return 1
+
+  return resp['Body'].read()
+
+
+def write_metadata(data):
+  '''
+  Write metadata file from byte stream.
+  '''
+  client = boto3.client('s3')
+  resp = client.put_object(
+      Body=data,
+      Bucket='release-metadata',
+      Key='release-versions'
+  )
+
+  if resp.ResponseMetadata.HTTPStatusCode != 200:
+    sys.stderr.write('Unable to upload file.  Dumping response metadata.\n')
+    print(resp, file=sys.stderr)
+    return 1
+
+
+def main(module_name, new_ref):
+  if not new_ref.startswith('refs/tags/'):
+    sys.stderr.write(
+        f'Unknown reference format {new_ref}.  Expecting refs/tags/v<version>\n')
+    return 1
+  # extract the version
+  new_tag = re.sub('[A-Za-z/]', '', new_ref)
+
+  print(f'Releasing version {new_tag} of module {module_name}')
+
+  release_data = fetch_metadata()
+  data = json.loads(release_data)
+  module_versions = data.get(module_name)
+  if not module_versions:
+    sys.stderr.write(
+        f'Module {module_name} does not exist in release metadata.\n')
+    return 1
+  if new_tag in module_versions:
+    print(f"Tag {new_tag} is already released for module {module_name}. Exiting.")
+    return 0
+  module_versions.insert(0, new_tag)
+  write_metadata(json.dumps(data).encode('utf-8'))
+
+
+def usage():
+  print("Usage: python3 update-release-metadata.py <module> <ref>")
+  return 2
+
+
+if __name__ == "__main__":
+  if len(sys.argv) != 3:
+    sys.exit(usage())
+  sys.exit(main(*sys.argv[1:]))