CI status updates sent as direct message to author of commit

[koonwen]

This PR changes the channel routing logic for CI updates. The old behavior used to send ci updates to the default channel specified in the config. The new behavior now sends the ci update as a direct message to the author of the commit.

How it works

The slack post_message api is able to send a direct message to a slack user by filling the channel field instead with the user_id. Since the Github commit author email and the slack profile email is the same, I have injected a new slack api call to get the user_id of a profile from a user's email address.

Test

expect tests in test/slack_payloads.expected have been updated showing the slack notifications being sent to the author of the commit via the user_id

References

#81

[rr0gi]

This will probably get complaints from people who didn't break build but push on top of broken build, the ideal solution should notify only the first person who broke build, but we can try with this simple solution, easy to revert if too much noise.

PS unrelated to PR but monorobot should be switched to slack lib cc @sewenthy

[Khady]

Since the Github commit author email and the slack profile email is the same

This isn't actually true for everyone. But I would say that it's still better than nothing. Later on we can figure out a way to inject a list of people.

[koonwen]

This isn't actually true for everyone. But I would say that it's still better than nothing. Later on we can figure out a way to inject a list of people.

@Khady Right, I thought that might be an issue. Initially I was hoping to have the lookup_user function use a dynamic cache but it could easily also load in some list of user mappings. I can look at adding that