feat(config): allow customisation of runtime group name (#440)

[mdonadoni]

Closes reanahub/reana-workflow-controller#561

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (36ce4e0) 36.35% compared to head (5cec305) 36.33%.

Additional details and impacted files

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##           master     #440      +/-   ##
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- Coverage   36.35%   36.33%   -0.03%     
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  Files          26       26              
  Lines        1576     1577       +1     
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  Hits          573      573              
- Misses       1003     1004       +1     

Files	Coverage Δ
reana_commons/config.py	0.00% <0.00%> (ø)

[tiborsimko]

Hmm, I wonder whether we need to create a new group name here at all. We do need to use the GID=0 during runtime for the appropriate workspace file access permissions, but cannot we simply use the default root group name directly without introducing a new "reana" group?

$ docker run -i -t --rm docker.io/library/ubuntu:20.04 /bin/bash -c 'grep :0: /etc/group'
root:x:0:

That said, it seems nice and consistent to introduce the new variable WORKFLOW_RUNTIME_GROUP_NAME instead of using hard-coded "root". But perhaps its default value could be simply "root" and not "reana"? And perhaps we might not actually need to create any such a group and just use the default?

[mdonadoni]

Yes, creating a new group is not needed if we keep WORKFLOW_RUNTIME_USER_GID set to zero. However that is needed if the GID is not zero, as otherwise the useradd call fails.

We can check whether the group already exists or not, and if it doesn't then groupadd is called. What do you think?

[mdonadoni]

I have updated reana-workflow-controller's PR to only create the group if there is no group with the given GID

[tiborsimko]

Sounds good. We may perhaps want to set WORKFLOW_RUNTIME_GROUP_NAME to be root by default, so that its value would correspond with WORKFLOW_RUNTIME_USER_GID's default value being 0.

[mdonadoni]

Regarding the default name, I would keep reana as I see two scenarios:

• gid is zero, so normally the root group already exists -> nothing to do
• gid is not zero, so we create a new group reana, as we cannot name this root

What do you think?

[mdonadoni]

After discussing among us, I have changed reana to root and I have also added a comment explaining what to do in case the group id needs to be changed.

[tiborsimko]

Yes, it's nice to have default values expressing the "reality", hence 0=root. And if someone would like to change them, they will find a little "how to" note on what to do.

[tiborsimko]

Works nicely. Left a minor comment about the default value of WORKFLOW_RUNTIME_GROUP_NAME.