Crashlytics integration akin to Bugsnag

[kitallis]

Context

This is the current set of health metics data stored by Tramline:

# Table name: release_health_metrics
#  daily_users                :bigint
#  daily_users_with_errors    :bigint
#  errors_count               :bigint
#  new_errors_count           :bigint
#  sessions                   :bigint
#  sessions_in_last_day       :bigint
#  sessions_with_errors       :bigint
#  total_sessions_in_last_day :bigint

We will need to transform the data from Crashlytics into a similar form and store it in Tramline.

Figure out the query required to get this data. Make sure to filter by the correct version code and version name.

Fetch frequency can be lower than Bugsnag (every 30 minutes?).

Once the data is fetched and stored, the rest of the health rule application logic remains the same. So, all that is needed from this issue to fetch, transform and store the release health metrics data.

Crashlytics is special because there's no direct API to get this data. We expect Firebase to be connected to the user's account, and we would make calls to the BQ dataset instead. Link to sample BQ data exported to a spreadsheet.

Requirements

• Write an API layer and integration layer for Crashlytics
• Ensure the interfaces adhere to the common functions, see Bugsnag integration

Acceptance Criteria

• UI change required only in connecting the integration, the rest should work seamlessly.
• Hook up the APIs and integration layer
• Unit tests & some API-mocked fixture-driven tests
• Ensure things work as closely as Bugsnag. Test manually properly.
• Find an estimate of the costs associated with each query. This will help us tweak polling rate and help communicate the unprecedented costs (if any) to our users.

Additional Notes

Here's a sample BQ query that can be used as a starting point for all the other queries to be written:

SELECT
  COUNT(DISTINCT event_id) AS number_of_crashes,
  FORMAT_TIMESTAMP("%F", event_timestamp) AS date_of_crashes
FROM
 `decoded-theme-355014.firebase_crashlytics.com_tramline_ueno_ANDROID_REALTIME`
GROUP BY
  date_of_crashes
ORDER BY
  date_of_crashes DESC
LIMIT 30;

[gitstart-connector]

Issue synced into GitStart. Please review, edit and hand it off to GitStart by following this link.

[gitstart-connector]

This issue has been handed off to GitStart: https://clients.gitstart.com/tramline/11653/tickets/TRAB-645

[kitallis]

Some additional definitions, referenced from https://bugsnagapiv2.docs.apiary.io/#reference/projects/releases/view-a-release

• errors_introduced_count: the new errors that have been introduced in this release
• errors_seen_count: the total errors that have been seen in this release
• sessions_count_in_last_24h: total number sessions for the release in the last 24h
• total_sessions_count: total number of sessions for the release
• unhandled_sessions_count: total number of sessions for the release that have had an exception/error
• accumulative_daily_users_with_unhandled: the total number of users in the release with errors
• accumulative_daily_users_seen: the total number of users in the release