Allow arbitrary user to run atlantis

[jocelynthode]

This PR should allow atlantis to run with an arbitrary uid.

This is particularly useful when running on Openshift for example where by default the uid is arbitrary.

Fixes issue #345

[codecov]

Codecov Report

Merging #346 into master will increase coverage by 0.12%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #346      +/-   ##
==========================================
+ Coverage    70.6%   70.72%   +0.12%     
==========================================
  Files          61       61              
  Lines        3681     3676       -5     
==========================================
+ Hits         2599     2600       +1     
+ Misses        901      895       -6     
  Partials      181      181

Impacted Files	Coverage Δ
server/events/vcs/github_client.go	74.11% <0%> (+0.3%)	⬆️
server/server.go	64.12% <0%> (+1.43%)	⬆️

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[jocelynthode]

@lkysow I removed the fsGroup from the helm chart is there something else to consider as well ?

[lkysow]

Please remove this line.

[jocelynthode]

I have removed the HOME environment variable.

However in the docker-entrypoint.sh I have changed the line added to /etc/passwd to:

echo "${USER_NAME:-default}:x:$(id -u):0:${USER_NAME:-default} user:/home/atlantis:/sbin/nologin" >> /etc/passwd

This way a user running the image on an openshift cluster won't have to set the HOME variable in their deployment to "/home/atlantis" and this way the shell is still setting it.

Is this ok with you ?

[jocelynthode]

I won't be able to test the image incorporating your changes and mine before monday. Could we wait until this to confirm everything is working as expected ?

[lkysow]

@jocelynthode sounds good. Please squash your commits into one if everything works.

[jocelynthode]

@lkysow I was able to test and everything works. However as expected the user has to specify the data dir or specify a HOME environment variable otherwise atlantis tries to clone in /.

I think we should maybe specify somewhere in the doc that the docker image expects either the HOME variable to be "/home/atlantis" or the data-dir variable to be set to "/home/atlantis" as this is currently the only folder that has the correct permissions

[lkysow]

Thanks for all your hard work! Yes I think I'll add an OpenShift section to the deployment docs.