refs https://github.com/TryGhost/Team/issues/2482
This change adds a small sleep in between dispatching events in the
worker thread that reads the events from Mailgun. That should reduce the
amount of queries we fire parallel to each other and could cause the
connection pool to run out of connections.
It also reduces the amount of concurrent sending to 2 from 10. Also to
make sure the connection pool doesn't run out of connections while
sending emails, and to reduce the chance of new connections falling back
on a (delayed) replicated database.
fixes https://github.com/TryGhost/Team/issues/2332
Saves events in the database and collects error information.
Do note that we can emit the same events multiple times, and as a result
out of order. That means we should correctly handle that a delivered
event might be fired after a permanent failure. So a delivered event is
ignored if the email is already marked as failed. Also delivered_at is
reset to null when we receive a permanent failure.
fixes https://github.com/TryGhost/Team/issues/2310
This moves the processing of the events from the event-processor to a
new email-event-processor in the email-service package.
- The `EmailEventProcessor` only translates events from
providerId/emailId to their known emailId, memberId and recipientId, and
dispatches the corresponding events.
- Since `EmailEventProcessor` runs in a separate worker thread, we can't
listen for the dispatched events on the main thread. To accomplish this
communication, the events dispatched from the `EmailEventProcessor`
class are 'posted' via the postMessage method and redispatched on the
main thread.
- A new `EmailEventStorage` class reacts to the email events and stores
it in the database. This code mostly corresponds to the (now deleted)
subclass of the old `EmailEventProcessor`
- Updating a members last_seen_at timestamp has moved to the
lastSeenAtUpdater.
- Email events no longer store `ObjectID` because these are not
encodable across threads via postMessage
- Includes new E2E tests that test the storage of all supported Mailgun
events. Note that in these tests we run the processing on the main
thread instead of on a separate thread (couldn't do this because
stubbing is not possible across threads)
There are some missing pieces that will get added in later PRs (this PR
focuses on porting the existing functionality):
- Handling temporary failures/bounces
- Capturing the error messages of bounce events
