RFC: Allow admins to override/extend the default pipeline config

[jolheiser]

woodpecker/shared/constant/constant.go

Lines 19 to 25 in c1adf2e

	// DefaultConfigOrder represent the priority in witch woodpecker search for a pipeline config by default
	// folders are indicated by supplying a trailing slash.
	var DefaultConfigOrder = [...]string{
	".woodpecker/",
	".woodpecker.yaml",
	".woodpecker.yml",
	}

---

I've created a jsonnet extension I plan to use, however right now (as far as I can tell) you need to manually set each repo to check for e.g. .woodpecker.jsonnet.

Assuming this would be useful for anyone else making config extensions, it would be great if the admin could override or extend the list of default paths to look for. I think I would prefer extending over overriding, but I've mentioned it in case anyone disagrees.

Just wanted to open a discussion before working on a PR, but I believe it should more or less be a matter of extending the array (using a slice instead) in the above linked file.
Whether it should also be reflected in the help text might be a bit trickier.

My thought is to just allow for WOODPECKER_EXTRA_DEFAULT_PIPELINE_CONFIGS="foo.jsonnet,bar.star".
The array will need to be converted to a slice, but a quick search leads me to believe that should not affect anything. The PR that added it didn't have any specific reason to make it an array.

[6543]

I would say just add a flag WOODPECKER_DEFAULT_PIPELINE_CONFIGS that uses our default value and anybody vmcan extend or chage it ...

[jolheiser]

That could work. Another thing that would potentially need to change is the dir functionality since it currently only checks for yaml files.

I am open to either, just liked the extending idea since then it would need to look up and repeat defaults if you wanted to add something.

[qwerty287]

This is actually a duplicate of #5428