This is a node.js project designed to be run with Google Cloud Functions.

Once the app is running as a Cloud Function, each time the function is invoked, it will go through all the Google Tag Manager containers listed in the config.json file, and query Google Tag Manager's API for what the most recent published version is.

If this version differs from the one in state (stored in a Google Cloud Storage file), a Slack message is pushed notifying about this.

Here are the things you need to have in order for the setup to work:

• Google Cloud Platform project with billing enabled.
• Cloud Functions API and Tag Manager API enabled in the project.
• A service account (you can use the default SA created by the Cloud Functions API) added as a READ user to each Google Tag Manager container you want to audit for changes to the published version.
• A Slack app per Slack workspace you want to publish messages to.
• An Incoming Webhook per GTM account/container, which forwards the message sent by the app to a given channel (or direct message) in the workspace.

It's also recommended to install the gcloud command-line tool.

The instructions for setting up the integration are detailed in this blog post (FORTHCOMING).