gitlab eventsource support for groups

[jwillker]

Is your feature request related to a problem? Please describe.
My company has a GitLab with a lot of groups and subgroups with thousands of projects, so if I want to create an event source to listen to all my company webhooks or a particular group is a huge pain to write all in an EventsSource object, and maintain this updated is another pain, because everyday new projects die and born.

E.g:

apiVersion: argoproj.io/v1alpha1
kind: EventSource
metadata:
  annotations:
  name: gitlab-webhook
  namespace: argo-events
spec:
  gitlab:
    my-company:
      events:
      - JobEvents
      gitlabBaseURL: https://gitlab.my-company.com/api/v4
      projects:
      - my-company/group1/subgroup1/projectA
      - my-company/group1/subgroup1/projectB
      - my-company/group1/subgroup1/projectC
      - my-company/group2/subgroup1/projectA
      - my-company/group2/subgroup72/projectZ
      - ....

I have about 8k projects now 😢

Describe the solution you'd like
It would be nice if the GitlabEventSource had a new field, group that accepts a group path and create the webhook at the group level instead of a specific project. This allows us to receive events from a specific group or all the groups of the company.

Describe alternatives you've considered
Other solutions that I can take is create a EventsSource to a unique project and use their listener URL to create manually a webook in some GitLab groups. This works I have tested but its is ugly and depend of manual actions for each Group.

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[neo502721]

@whynowy I've done some development and I'm testing it now. Can you assign to me ?

[jwillker]

Hey @whynowy and @neo502721, great implementation, but with a little bug:

The group hook is created just like the project hook but missing the secret token.

I`m just opening a PR to fix this: #2550.