PDK as a general purpose Puppet validator

[natemccurdy]

Use Case

It's annoying when I'm helping folks learn Puppet or improve their existing Puppet code that the PDK requires it to be run from within a PDK'ified module. Some times all you want to do is puppet-lint a random manifest in your home directory or puppet parser validate some old module code that hasn't been converted to the PDK.
As it is today, this is impossible to do unless you create a PDK'ified module, cd into it, then run your pdk commands.

The PDK solves the problem of bringing a Ruby environment + Puppet + useful gems onto a system using native packages. I'd very much like to leverage that to be able to run pdk validate from anywhere on my system to validate arbitrary Puppet code.
I don't want to have re-invent the wheel of installing Ruby+Puppet+Gems seeing as all that is already on my system.

I think this same feature set would make it easy to run pre-commit hooks on a monorepo or validate/unit test code without having to cd to that module first.

Describe the Solution You Would Like

Example 1: From my home directory, I want to validate Puppet code:

~ $ pdk validate some/non/module/path/foo.pp
~ $ pdk validate some/non/module/dir/

Example 2: From my home directory, I want to run specific linters:

~ $ pdk validate --linters=puppet-lint arbitrary/path/foo.pp
~ $ pdk validate --linters=rubocop arbitrary/path/foo.rb

Example 3: Executing unit tests for a module while you're in ~

~ $ pdk test unit --module /a/module/in/a/sub_directory

Example 4: Running unit tests on all sub-directories that are modules

~/control-repo $ pdk test unit site-modules/

[glennsarti]

Initial thoughts

Examples 1 and 2 should be relatively easy-ish to do as validate doesn't require state to be saved in a module directory.

Examples 3 is probably easy to do. Even a hacky fix like changing cwd on the fly would do it.

Example 4 looks complicated due to spec fixtures. Also your description says "Running validators" but your code is "test unit" So I'll assume you meant Running testers

[natemccurdy]

Ah good catch, yes I did mean running unit tests for Example 4. I've updated my original comment.

For a comparison of the kind of thing we have to do now to get Example 1 working, I've created a Gemfile in my home directory that is a copy of PDK's, and also stubbed out a minimal metadata.json in my home directory.
This lets me run the following from ~:

[nate@laptop ~ ]$ pdk bundle exec puppet-lint relative/path/to/manifest.pp