Update Compass DB after a user changes recurring event(s) in Google Calendar

[tyler-dane]

Feature Description

Functionality

1. Signup/login for compass
2. Make change in compass or gcal
3. Wait a few seconds
4. Event is updated in Compass

Use Case

Additional Context

Acceptance Criteria

Implementation

Gcal will submit a notification saying something changed, and the Compass backend will need to determine whether the change included recurring events and, if so call the correct event service method (from #321)

• Determine if Compass already has the most recent event data in its database or not. This is the key step that could improve performance. Because if the user made the change in Compass, then we know that Compass has the most up-to-date data in its database already and can thus ignore the google notification to avoid recreating the same data we already have. This would save network requests and time.
  • Keep in mind, though, that determining where the event came from might be tricky. If it becomes too complicated, then ignore this requirement. It's acceptable to let us rewrite the same data for this PR if needed. In the future we can optimize.
• After determining whether to process the change or not, check if the new event data from gcal already exists in the Compass database. You can probably do this by looking up the google event id.
• If it does exist in our database already, then update it with the new data. This will likely involve making a new call to gcal API, as the gcal notification response doesn't include the full payload for the updated event(s)
• If it doesn't exist in our database, that means the user created a new event in google calendar. In this case, create a new document in the compass database.