Hi, I wanted to bring up a conversation in hopes that we as a community can create a specification for something I am calling module schemas. Before I get into that I want to provide a little background info.
This all started a few years ago when hiera first came out. Data seperation in the form of parameters and auto hiera lookups quickly became the norm and reusable modules exploded into what the forge is today . Because of the popularity of hiera, data validation is now a major problem though. Without good data, excellent modules become useless. Puppet 4 and stdlib brought many new functions and ways to validate incoming data, and I consider puppet 4 to now be a loosely typed language now. Hell, there was even this a long time ago: https://github.com/puppetlabs/puppetlabs-kwalify <https://github.com/puppetlabs/puppetlabs-kwalify> But puppet only does so much, and while having validation reside in code might make troubleshooting a snap, there is still a delay in the feedback loop when the code is tightly coupled with an external “database” of data. Data that is inserted by non puppet developers who don’t know YAML or data structures. So with that said I want to introduce something new to puppet module development, called module schemas. A module schema is a specification that details the inner workings of a module. For right now this means a detailed specification of all the parameters for classes and definitions used inside a module who’s goal is to make it impossible to insert a bad data structure. But ideally, we can specify so much more (functions, types, providers, templates) even hiera calls in weird places like templates and functions, which are usually things that do not get documented and are hard to reference and usually requires looking at source code. What does such a schema look like? Here is a example schema for the apache module which contains 446 parameters!. https://github.com/logicminds/puppet_module_schemas/blob/master/apache_schema.yaml The most immediate use case for such a schema is hiera validation as I have outlined here: http://logicminds.github.io/blog/2016/01/16/testing-hiera-data <http://logicminds.github.io/blog/2016/01/16/testing-hiera-data>. Which works AWESOME!. We are validating hiera data and not YAML and doing it under 500 ms for every commit on every single file. As a community we need a solution for validating hiera data. Its my belief that schemas are the way to go. After all hiera data is now in modules with no way to easily validate. Other use cases that come to mind: - generating documentation (Many modules on the forge usually contain a static map of parameters used inside the module). If a schema was present, we could just generate that same map automatically. - useful for other 3rd party tools like puppet strings Parameter specification lookup - Imagine a face that shows internal puppet module specifications. I am not talking about puppet-strings, this would detail the parameters given a class, or an example parameter value given a parameter name. Scenario: - puppet module puppetlabs/apache (outputs all the parameters, classes for that module) in a specified format (json or yaml) - puppet module puppetlabs-apache::class_name (outputs all the parameters for the class in a specified format (json or yaml) - puppet module puppetlabs-apache::class_name::param1 (outputs an example value for that parameter, as well as the default value) in a specified format (json or yaml) Foreman and Puppet Console need this level of detail as well. Currently, both of these solutions spend quite a bit of time parsing code to show parameters for UI display. It would be much easier if a schema was available that detailed this level of data. Think of the speed improvements that could be had if this information was “cached” in a file. These solutions currently load or intelligently scan all the puppet code for every puppet environment to get the parameters and defaults. Here is how we can create a schema http://logicminds.github.io/blog/2016/01/15/how-to-build-a-module-schema/ <http://logicminds.github.io/blog/2016/01/15/how-to-build-a-module-schema/> (which I even automated with retrospect-puppet (https://github.com/nwops/puppet-retrospec.git <https://github.com/nwops/puppet-retrospec.git>) However, we all need to agree on something before schemas can ever be a “thing”. We need a schema for module schemas. This is important because as soon as 3rd party tools or scripts start to use schemas and later we decide the schema needs changing, everything breaks. Tools need a specification to work from. So with this in mind and an example schema here: https://github.com/logicminds/puppet_module_schemas/blob/master/apache_schema.yaml <https://github.com/logicminds/puppet_module_schemas/blob/master/apache_schema.yaml>. How can this be improved? What should we add? About the only change I was pondering was adding another object for the types themselves. https://github.com/logicminds/puppet_module_schemas/blob/master/specification_with_types.yaml <https://github.com/logicminds/puppet_module_schemas/blob/master/specification_with_types.yaml> What are your thoughts? What steps do we need to take to make this a supported specification? What would you desire in a module schema? Am I the only one that thinks this is a killer solution? Corey Osman -- You received this message because you are subscribed to the Google Groups "Puppet Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to puppet-dev+unsubscr...@googlegroups.com. 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