config: add global mattermost_api_url and mattermost_api_url_file

[madest92]

Default Mattermost receiver webhook_url/webhook_url_file from global settings

[TheMeier]

Since #4812 was merged could you please try to follow it's pattern where possible?

[madest92]

Since #4812 was merged could you please try to follow it's pattern where possible?

I've reviewed the changes. This doesn't apply to mattermost_api_url/mattermost_api_url_file.

Conflict fixed.

[madest92]

@TheMeier
I'd actually like to do a small refactoring of the MM configuration. Sending messages via attachment, like in Slack.
Move the attachments up a level and add the define templates.

Now you need to write like this:

mattermost_configs:
  - webhook_url: '.....'
    username: '{{ template "__alertmanager" . }}'
    text: ''
    attachments:
      - color: '{{ if eq .Status "firing" }}danger{{ else }}good{{ end }}'
        title: '{{ .CommonAnnotations.summary }}'
        title_link: '{{ template "__alertmanagerURL" . }}'
        text: '{{ range .Alerts }}{{ .Annotations.description }}{{ end }}'

Instead of

mattermost_configs:
  - text: 'if you want update default'
    title: 'if you want update default'
    ....

What do you think about this?
Yes, it will break the current behavior. But it will be more familiar to everyone.

I can submit changes as part of this merge request, or create a new one once the current one is accepted.
What's best?

[TheMeier]

I personally think this should be two separate changes. Adding something is a completly different beast than breaking changes.

[madest92]

Okay, then I'm waiting for the current changes to be accepted.

[madest92]

@TheMeier hi

Do you have any comments on Mr?

[madest92]

@TheMeier hi. Who can give a second approval and merge the changes?

[TheMeier]

I think this is now resolved via #4998

[guoard]

Hi @madest92,

I just realized that you had opened a PR for the same feature before mine was merged. I'm sorry I didn't check for similar open PRs beforehand, I should have looked more carefully before submitting mine.

Thank you for your work on this, and apologies again for the overlap.