ci: Post a message on Slack when a new release is published

.github/workflows/release-notification-on-slack.yml

@@ -0,0 +1,19 @@
+name: Slack Post
+on:
+  # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#release
+  release:
+    types: [published]
+jobs:
+  build:
+    name: Slack Post
+    runs-on: ubuntu-latest
+    steps:
+      - run: |
+          echo "New release published ${GITHUB_REF}"
+          pip3 install PyGithub
+          ./bin/announce_release_on_slack.py
+        env:
+          GITHUB_RELEASE_TAG: ${{ basename GITHUB_REF }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
+          SLACK_CHANNEL_ID_RELEASES: ${{ secrets.SLACK_CHANNEL_ID_RELEASES }}

bin/announce_release_on_slack.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+
+# (c) Copyright IBM Corp. 2023
+
+import json
+import logging
+import os
+import re
+import requests
+import sys
+
+from github import Github
+
+
+def ensure_environment_variables_are_present():
+    required_env_vars = ('GITHUB_RELEASE_TAG', 'GITHUB_TOKEN',
+                         'SLACK_BOT_TOKEN', 'SLACK_CHANNEL_ID_RELEASES')
+
+    for v in required_env_vars:
+        if not os.environ.get(v):
+            logging.fatal("A required environment variable is missing: %s", v)
+            sys.exit(1)
+
+
+def get_gh_release_info_text_with_token(release_tag, access_token):
+    g = Github(access_token)
+    repo_name = "instana/ruby-sensor"
+    repo = g.get_repo(repo_name)
+    release = repo.get_release(release_tag)
+
+    logging.info("GH Release fetched successfully %s", release)
+
+    msg = (
+        f":mega: :package: A new version is released in {repo_name}\n"
+        f"Name: {release.title}\n"
+        f"Tag: {release.tag_name}\n"
+        f"Created at: {release.created_at}\n"
+        f"Published at: {release.published_at}\n"
+        f"{release.body}\n")
+
+    logging.info(msg)
+    return msg
+
+
+def reformat_github_md_to_slack_markup(msg):
+    # Based on:
+    # https://github.com/atomist/slack-messages/blob
+    # /c938c67e957345ba6a0015ca3ace1fd779d0979c/lib/Markdown.ts#LL111C1-L116C44
+
+    msg = re.sub(r'^(\s*)[-*](\s+)', r'\1•\2', msg, flags=re.MULTILINE)
+    msg = re.sub(r'(\*|_)\1(\S|\S.*?\S)\1\1(?!\1)', r'<bdmkd>\2</bdmkd>', msg)
+    msg = re.sub(r'(\*|_)(?!\1)(\S|\S.*?\S)\1(?!\1)', r'<itmkd>\2</itmkd>', msg)
+    msg = msg.replace('<bdmkd>', '*').replace('<itmkd>', '_')
+    msg = re.sub(r'^([#]+)\s+([\S ]+)$', r'*\2*', msg, flags=re.MULTILINE)
+
+    # TODO: The message text has to have a partial entity encoding
+    # https://api.slack.com/reference/surfaces/formatting#escaping
+    # Validate it if we can?
+    # A naive replace like this is not enough, because
+    # it might already be encoded and then we would encode again.
+    #s = s.replace('&', '&amp;')
+    #s = s.replace('<', '&lt;')
+    #s = s.replace('>', '&gt;')
+
+    # Use the tester here:
+    # https://api.slack.com/methods/chat.postMessage/test
+    return msg
+
+
+def post_on_slack_channel(slack_token, slack_channel_id, message_text):
+    api_url = "https://slack.com/api/chat.postMessage"
+
+    headers = {"Authorization": f"Bearer {slack_token}",
+               "Content-Type": "application/json"}
+    body = {"channel": slack_channel_id, "text": message_text}
+
+    response = requests.post(api_url, headers=headers, data=json.dumps(body))
+    response_data = json.loads(response.text)
+
+    if response_data["ok"]:
+        logging.info("Message sent successfully!")
+    else:
+        logging.fatal("Error sending message: %s", response_data['error'])
+
+
+def main():
+    # Setting this globally to DEBUG will also debug PyGithub,
+    # which will produce even more log output
+    logging.basicConfig(level=logging.INFO)
+    ensure_environment_variables_are_present()
+
+    msg = get_gh_release_info_text_with_token(os.environ['GITHUB_RELEASE_TAG'],
+                                              os.environ['GITHUB_TOKEN'])
+
+    slack_formatted_msg = reformat_github_md_to_slack_markup(msg)
+
+    post_on_slack_channel(os.environ['SLACK_BOT_TOKEN'],
+                          os.environ['SLACK_CHANNEL_ID_RELEASES'],
+                          slack_formatted_msg)
+
+
+if __name__ == "__main__":
+    main()