The googlechat channel is a Chat app with an HTTP endpoint. Chat posts events to Habakkuk's HTTP server with a bearer token Google signs for the app's audience; replies go through the Chat API, authorized as the app's service account.

Note

Google Chat is a webhook channel: it needs an http section with a public_url that Google can reach.

Set it up#

In a Google Cloud project, enable the Google Chat API.
Create a service account and a JSON key for it. Replies are sent as this account.
In the Chat API configuration, set the app's connection to an HTTP endpoint URL of <public_url>/channels/<name>, for example https://habakkuk.example.com/channels/gchat.
Note the Authentication Audience you chose there: the project number, or the endpoint URL.
Configure the channel:

yaml

channels:
  gchat:
    type: googlechat
    googlechat:
      audience: "123456789012"                   # the project number or endpoint URL set as the Authentication Audience
      credentials_env: GOOGLE_CHAT_CREDENTIALS   # the service account's JSON key, or a path to it
http:
  listen: 127.0.0.1:8484
  public_url: https://habakkuk.example.com

Chat apps built as Google Workspace add-ons work too.

Access#

allow_from takes the sender's email address or their Chat user name (users/123456789). Anyone else who sends a direct message gets a pairing code.

Spaces and threads#

In spaces the bot answers when mentioned, and replies in the thread.

What works#

Text and uploads in.
Text out, in the thread.
No typing indicator or buttons: approvals are answered with yes or no.

Troubleshooting#

Symptom	Cause and fix
Every event is refused	`audience` does not match the Authentication Audience in the Chat API configuration.
Events arrive but replies fail	Check `credentials_env` holds the service account's JSON key (or a path to it), and that the Chat API is enabled.