skip all pipelines based on what is in the PR

[matttrach]

Proposed Changes

This change will add a pipeline which implements drone-skip-pipeline.
The purpose is to provide some mechanism to automatically skip pipelines which are not necessary due to the files that are being changed. For example, if a markdown file is the only file changed, then we don't need to run functional tests. This will reduce our integration time.

Types of Changes

No new code to k3s, all changes in .drone.yml

Verification

Unfortunately, Drone provides no way to test this outside of letting it run in your repo.

Linked Issues

This addresses #6980.

User-Facing Change

This has no user facing change.

Further Comments

There is another plugin which may give us similar functionality, but is out of date and requires configuration on the drone server, I would like to try this one first to avoid the additional handoffs.
There is more than one way to implement this plugin, the way I have provided is the one with the fewest changes to existing steps, I am open to additional suggestions.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 9.65%. Comparing base (ea094d1) to head (52e532d).
Report is 724 commits behind head on master.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #6996   +/-   ##
======================================
  Coverage    9.65%   9.65%           
======================================
  Files         146     146           
  Lines       10738   10738           
======================================
  Hits         1037    1037           
  Misses       9483    9483           
  Partials      218     218           

Flag	Coverage Δ
unittests	9.65% <ø> (ø)

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[brandond]

I'm not sure what's going on with all the commits that have been added to this branch after approval; please get it back to just the single change before merging.

[matttrach]

sorry, I will. I was finally able to test this and it doesn't work... :(
The plugin is only compiled on amd64, I think I will need to head back to the drawing board on this one.

[matttrach]

converting this to a draft so I don't spam reviewers

[matttrach]

I put everything into a single commit, I believe this is ready for review.

[matttrach]

the diff is unclear here, but if you look at the file I just removed some spacing here to conform to the way the rest of the yaml is written (lists have same spacing as parent)

[matttrach]

This is a trivial spacing change to validate that .md files are ignored.

[cwayne18]

This looks neat thanks! Can we add .github/*, MAINTAINERS, CODEOWNERS to the skip list please?

[matttrach]

done. Also added DCO, channel.yaml, and LICENSE (although they are unlikely to change)

[dereknola]

Is is possible to put all the repeated bash commands into a script file and just call that?

[matttrach]

I think the special exit code has to be executed from the root scope, I can probably add a file and execute it, but it would only reduce 1 line of code per copy.

[brandond]

Do we want this on all CI runs, or just on PR? It feels like we should never skip running CI on merges or tags - basically anything that runs on drone-publish. Should we add something to restrict this to just pull branches on drone-pr?

trigger:
  instance:
  - drone-pr.k3s.io
  ref:
  - refs/pull/*/head

[matttrach]

Definitely don't wanna skip on tags, thanks!
I think bounding the skip to pushes and pull requests should give us a good compromise for how often.

[ivan-claire]

Looks good to me.