Replace regex with winnow based parser
#255
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This file is intended to define valid `Procfile` inputs and parser behavior separate from implementation. It may be updated in the future based on upstream requirements (CNB spec or kubernetes spec) or through future discussion.
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| # CNB Procfile format specification | |||
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I like that this exists, but I wonder if this spec should be shared/enforced more widely?
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shared
You mean you're wanting more feedback from a diverse group of people (such as other Heroku teams) or you're wanting to promote the format to a larger group outside of Heroku such as language communities (or both)?
I'm open to both. I'm also open to suggestions. Perhaps we link to the SPEC from the readme and make it more prominent.
enforced
We could share the logic by providing a stand-alone parser utility that converts it to some other format like json or toml. We could start by calling both parsers in cedar and instrumenting failures. While people are using # like comments in today's procfile, technically any leading character would work //.
I also had the idea that I could expose the parser or ship it via crates.io so that other buildpacks could use it. Some buildpacks have logic like "If app has a Procfile..." but it would be more robust to share the same parsing logic.
Getting a little ahead of myself. We could also consider upstreaming RFC 1123 to the CNB spec to make it more clear so then it's not "the procfile buildpack supports the intersection of kubernetes and CNB" and then becomes simply "the procfile buildpack supports the CNB spec".
* Use "separated" instead of terminated/preceded * Add a missing word * Specify that spaces are not part of they key * Document duplicate key behavior
Replace the existing
Regexbased "parser" with an actual honest-to-goodness parser/combinator based parser.Procfilevalidation more strict #73How to review
Some suggestions on how to review this:
procfile.rs. Some of them were useful for development, the majority are asserting overall behavior and edge cases