I think this is an interesting idea, I always wanted to do plugins for adding extra string formats.

What kind of uses would this unlock beyond what you can achieve with the template config file? I'm not against it, just curious what you have in mind

As far as I'm aware the template config file doesn't let you alter the way in which templates are processed, it just lets you configure which templates are used, the output filename, etc. But if I am missing something let me know.

With this plugin setup you are able to add additional functions to the funcmap for template processing. For a silly example, let's say you needed to use a rot13 function in your templates.

You can write the following plugin:

package main

import "text/template"

func rot13(s string) string {
	// implement me
	return s
}

func AddFuncs(f template.FuncMap) {
	f["rot13"] = rot13
}

Build it as a plugin, which will create plugin.so:
go build -buildmode=plugin plugin.go

Use your plugin function within one of your custom templates:
{{ rot13 .Item }}

And then run swagger generate using the plugin:
swagger generate cli -t gen --spec=spec.json -T templates -p plugin.so

I do not actually have a specific use-case that needs this at the moment, but the idea is that in the future if you need some additional templating functionality you don't need to add it to the go-swagger codebase like I did with #2741, you can just pull in your own plugins and modify them as needed.

Fixed up an issue with tests and got the windows build fixed. The failing AppVeyor tests are due to an unrelated issue (#2762).

@casualjim Curious if you have any further feedback on this, and my explained use case above.

This looks good to me

This model could also be used for strfmt extensions which is an often requested feature

This looks good to me

This model could also be used for strfmt extensions which is an often requested feature

Thanks Ivan! Should be ready to merge now.

I will look into the strfmt use case as well.