Override config via environment

[jbergstroem]

When playing with dockerfiles and multiple repos (main usecase for me is part of CI) it would be nice to be able to override specific config settings via environment; for instance YAMLLINT_CONFIG="line-length.max=81" yamllint foo.yaml. This makes it easier to override a few settings without having to check in a config in each repo you're testing against.

[adrienverge]

I agree it could be cool. But I'd rather have a YAML-formatted config, like for the -d option.

By the way, did you know you can already use this?

YAMLLINT_CONFIG="{extends: relaxed, rules: {line-length: {max: 81}}}"
yamllint -d "$YAMLLINT_CONFIG" foo.yaml

[jbergstroem]

@adrienverge said: did you know you can already pass config as env?

Didn't. Thanks!

@adrienverge said: YAMLLINT_CONFIG=..

I considered format as well; suggested something different than YAML in my original comment because I felt a simpler dot notation was closer to your average bash experience. I guess it doesn't scale as well, but the idea was to have the option of changing "just the one thing"; not really passing a full config.

I guess there are two minor opportunities for improvements here. Consider a use case similar to:

# Override while calling this docker instance in your CI pipeline
ENV YAML_ARGS=""

# ...

CMD ["yamllint", "-d '${YAML_ARGS}'"]

..and overriding this from your ci script.

1. Allowing "empty" configs by assuming they default:

$ docker run --rm -v $(PWD):/yaml sdesbure/yamllint yamllint -d "" .gitlab-ci.yml
invalid config: not a dict

2. Avoiding -d by reading a defined environment variable

I guess both can be handled in wrappers but I thought it be worth bringing it up. Feel free to close this issue unless you feel we should make either improvement actionable.

[adrienverge]

Hey,

Both 1. and 2. make sense!
Contributions are welcome (they need to come with tests).

[grzesuav]

@adrienverge When I have config in file and want just to override one rule, can I do it with existing mechanism somehow ?

[adrienverge]

@grzesuav you can do this:

YAMLLINT_CONFIG="{extends: /my/config/file.yaml, rules: {line-length: {max: 20}}}"
yamllint -d "$YAMLLINT_CONFIG" foo.yaml

[grzesuav]

ok, thanks :)

anyway I think overriding specific setting with env variable would be useful in this case. Do you have any preference around the behavior ?