feat(slack): Add slack service

[caseyhebebrand]

Introduces a Slack service that is conditional on the presence of a token. The initial use case is to fetch public channels within a workspace.

[spinnakerbot]

We prefer that non-test backend code be written in Java or Kotlin, rather than Groovy. The following files have been added and written in Groovy:

• gate-web/src/main/groovy/com/netflix/spinnaker/gate/config/SlackConfig.groovy

• gate-web/src/main/groovy/com/netflix/spinnaker/gate/controllers/SlackController.groovy

• gate-web/src/main/groovy/com/netflix/spinnaker/gate/services/SlackService.groovy

See our server-side commit conventions here.

[spinnakerbot]

The following commits need their title changed:

• 90e4dc6: Fetch channels from Slack

• 9c4456b: Remove archived channels

Please format your commit title into the form:

<type>(<scope>): <subject>, e.g. fix(kubernetes): address NPE in status check

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[srekapalli]

Few minor observations. Also tests are missing :).

[emjburns]

I'd love for you to convert these files to java. We are trying to not add any more groovy code. That means that parsing the response from slack will be more of a pain in the ass, but it should be fine. Let me know if you need help or an example file to work from

[caseyhebebrand]

I'd love for you to convert these files to java. We are trying to not add any more groovy code. That means that parsing the response from slack will be more of a pain in the ass, but it should be fine. Let me know if you need help or an example file to work from

No worries, I can do that.

[jeyrschabu]

lgtm.

(I personally don't see value in a single unit test that would just assert that a mock got invoked)

[jeyrschabu]

Can you ensure gate starts up normally even without this config. Just so we don't break folks in OSS

[caseyhebebrand]

I added another @ConditionalOnProperty to check for the url as well

[emjburns]

Speaking from lots of experience, it's best to make sure that gate starts up locally without this property as well as with this property. I've broken OSS several times because I forgot to check that :)

[caseyhebebrand]

Confirmed that gate OSS runs without any slack config :)

[caseyhebebrand]

lgtm.

(I personally don't see value in a single unit test that would just assert that a mock got invoked)

I agree, especially since this is just proxying to slack with no other business logic.

[jeyrschabu]

I think this is fine since the controller is the only thing depending on SlackService.

Another approach would be to annotate this controller with @ConditionalOnBean(SlackService.class) then annotate SlackConfig.slackService with @ConditionalOnProperty("slack.....") but you don't have to do this. (maybe until slackService gets used elsewhere)