Add the ability to disable Atlantis locking a repo

[gezb]

This change introduces a no-op Locker implementation that when enabled effectively disables the locking of projects and workspace

This is another possible solution to #1212, my initial change just automatically unlock after a plan had run (#1258)

[codecov]

Codecov Report

Merging #1340 (6cf783f) into master (6b36adb) will increase coverage by 0.02%.
The diff coverage is 86.95%.

@@            Coverage Diff             @@
##           master    #1340      +/-   ##
==========================================
+ Coverage   70.01%   70.03%   +0.02%     
==========================================
  Files          74       74              
  Lines        5556     5570      +14     
==========================================
+ Hits         3890     3901      +11     
- Misses       1307     1308       +1     
- Partials      359      361       +2     

Impacted Files	Coverage Δ
cmd/server.go	79.09% <ø> (ø)
server/events/comment_parser.go	93.98% <ø> (ø)
server/user_config.go	100.00% <ø> (ø)
server/server.go	61.97% <50.00%> (-0.28%)	⬇️
server/events/locking/locking.go	100.00% <100.00%> (ø)
server/events/markdown_renderer.go	92.30% <100.00%> (+0.09%)	⬆️

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[gezb]

I'm not sure if I should also not render To delete all plans and locks for the PR, comment: atlantis unlock when commenting back on the pr if this option is enabled?

[acastle]

Definitely a bigger fan of this approach than #1258. Disabling the unlock message as you have done seems appropriate to me as this is what we have done for other flags in the past.

[acastle]

LGTM 🚀

[kevincox]

I have one question about this. Forgive me for not understanding Atlantis internals.

This seems to disable the automatic lock taken by Atlantis. I think this is very helpful. However does the current approach allow manual locking? For example when doing manual work or otherwise applying outside of Atlantis it often is useful to take a "manual" lock. Would this be incompatible with that?

[gezb]

Hi @kevincox yes this option would be incompatible with taking a manual lock as the call to take any repo/project lock does not do anything,

When I revisited this I looked at the easiest way to disable locking without having to make too may changes to the internals of Atlantis because a lot of the comments on the issue around this and my other attempt were along the lines of why bother locking if you are just unlocking once the plan had been run and pointing out the fact that Terraform does it own locking

[kevincox]

I think this is still an improvement as currently our team just ignores locks anyways because most of them are pointless. However it would be nice at some point in the future to have support for manual locking. Since the noise is down this would provide a clear signal that someone is working on something.