My application uses the Push Notifications API (also known as Channel Subscriptions or Webhooks in the documentation) with the Reports API to get real-time updates about auth tokens.
Every 6 hours, our application makes a request to https://www.googleapis.com/admin/reports/v1/activity/users/all/applications/token/watch (as per the documentation at https://developers.google.com/admin-sdk/reports/v1/reference/activities/watch and https://developers.google.com/admin-sdk/reports/v1/guides/push). That request includes address=https://example.com/google_tokens. That URL then immediately receives a "sync" request with no body, but headers like this:
X-Goog-Channel-Expiration: Fri, 19 Oct 2018 20:55:08 GMT
X-Goog-Channel-ID: 62c1c0ed-8519-4f00-836f-2cbc113a1d2e
X-Goog-Message-Number: 1
X-Goog-Resource-ID: JfrjzGpcrVZETb17lpUzzOEVbDw
X-Goog-Resource-State: sync
X-Goog-Resource-URI: https://www.googleapis.com/admin/reports/v1/activity/users/all/applications/token?alt=json
Until about 8 days ago, we would then start getting requests at that URL whenever someone uses GSuite SSO to sign into another app. We are still getting the sync requests, but no other push notifications have been received. We aren't getting any data from this API any more. Prior to 8 days ago this was all working perfectly. We have not made any changes to that infrastructure.
The last non-sync webhook was received around 2018-10-11 22:00 UTC. We are still getting the sync requests whenever we use the /watch API.
We have another application on the same infrastructure that also uses the Push Notifications API, but for admin/directory/v1/users instead. That application has been working perfectly all this time. So, what could be causing us to not receive anything after the sync requests for tokens?
