fix(slack): replace slack GetChannels by GetConversations

[thlacroix]

fixes #1210

channels.list has been deprecated by slack and will break for existing applications in February 2021 (always breaks for new applications).

This PR replaces this call (used to check that the specified channel exists) by the new conversations.list which should by default work in a similar way.

It was needed to bump github.com/nlopes/slack as GetConversations was not available in the current version, but I decided not to go up to the latest as they changed the signature of PostMessage, which was trickier to mock in the tests.

[codecov]

Codecov Report

Merging #1350 (debd858) into master (6b36adb) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1350      +/-   ##
==========================================
+ Coverage   70.01%   70.05%   +0.03%     
==========================================
  Files          74       74              
  Lines        5556     5563       +7     
==========================================
+ Hits         3890     3897       +7     
  Misses       1307     1307              
  Partials      359      359              

Impacted Files	Coverage Δ
server/events/webhooks/slack_client.go	96.36% <100.00%> (+0.53%)	⬆️

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[lkysow]

LGTM

[thlacroix]

Hi @lkysow , when do you think this can be released ?
In February all deployments which currently use the slack integration successfully will break and won't be able to start with their current configs (removing the webhook config would fix it though), so if this can be available by the end of the month that would be great.

[emre141]

@nishkrishnan Do you know about when would be able to new release that is cover this fix ?

[lkysow]

we're going to try and get one out next week

[jmreicha]

Can somebody share a working configuration? I'm still getting initializing server: parsing /repos.yaml file: yaml: unmarshal errors: line 33: field webhooks not found in type raw.GlobalCfg using the following config in my repos.yaml config. I am setting the slack token via environment variable.

...
webhooks:
  - event: apply
    kind: slack
    channel: test-channel

[emre141]

@jmreicha I was used to deploy via helm as following, the link about configmap that is keeping following slack config

https://github.com/runatlantis/helm-charts/blob/main/charts/atlantis/templates/configmap-config.yaml

config: |
  slack-token: "{{ .Values.optiva_slack_token  }}"
  webhooks:
    - event: apply
      kind: slack
      channel: jpn-saasops-imp
      workspace-regex: optiva-inc.slack.com

[jmreicha]

Ah ok, so it needs to be in a separate atlantis.yaml configuration then? That's the only difference I'm seeing.

[jmreicha]

Splitting the configurations seems to work, erroring now with initializing server: initializing webhooks: missing_scope. Is there a list of minimum scopes needed? I have chat:write and incoming-webhook.

[jmreicha]

For anybody else that comes across the error, these permissions seem to be enough to fix it - channels:read, chat:write, groups:read, im:read, incoming-webhook, mpim:read.