Addon setup - `ponzu get github.com etc` about ponzu

[nilslice]

@olliephillips - I like the idea, and agree it would probably be very helpful for quickly getting addons and integrating them into the project.

Hows this for a modified version of your proposal:

# this would run: go get -u github.com/bosssauce/fbscheduler
# and copy that package into ./addons
$ ponzu add github.com/bosssauce/fbscheduler

This way the code completion will work straight away and the addon becomes vendored upon the next build.

I'm concerned that automatically adding _ imports to some file is a fix for behavior that I'm not sure we want to encourage.. will have to get more feedback on what the downside of this could be. My worry is that without explicitly importing the addon package somewhere, we open up ourselves to having to somehow determine if the _ import should be made (and is safe to do so), or add more API & documentation so the developer knows how to trigger this auto import..

I guess its a question of how much "magic" is going on which could end up causing more hurt than good. There is already one instance of this in cmd/ponzu here: https://github.com/ponzu-cms/ponzu/blob/master/cmd/ponzu/main.go#L19 but it's truly necessary so that the whole system knows about content types - which are fundamental. Addons could have unexpected side-effects, like you mention.

What if we added a package to the top-level of Ponzu, similar to the following, and move the content package import there replacing the _ "content" import in cmd/ponzu with _ "startup" import:

startup/run.go

// Package startup is meant to serve as a place to import packages to trigger 
// their initialization, start delayed workers, etc. `startup` is imported by the
// `cmd/ponzu` main package, and is run when the server starts up
package startup 

import (
    _ "github.com/ponzu-cms/ponzu/content"
    _ "github.com/bosssauce/fbscheduler"
)

This offers a place to put addon initialization in the event that an addon isn't tied directly to any one content type, but keeps the auto-initialization explicit (and optional), which I have a feeling will avoid potential issues in the future. Upon building, this startup package would be copied into the vendor directory just like content...

[olliephillips]

Yes, add is better than get. Much better. I'll have a stab at that feature if you can use - and not time critical?

Re auto-magically importing addons. Some of what you suggest I will have to digest in the morning - but generally, I think the Addon UX feels a bit odd having to trigger the import in code first, just to see the Addon admin suite in the dashboard.

[nilslice]

If you'd like to work on the feature, please go for it! And feel free to loop me in whenever needed. I'm typically in the #ponzu channel on this Slack if you'd like to join and discuss:
https://invite.slack.golangbridge.org

Take note that the CLI code changes should be made to the ponzu-cms/ponzu package itself, not a project that you create with ponzu new - and there are some contribution docs in the README. You'll need to run $ go install ./... from the ponzu-cms/ponzu package or if you fork it, from your own fork (then using the -fork flag as shown in the README) - sorry if this is all obvious, just trying to leave notes wherever possible so others might find them if they are having trouble contributing.

I would also suggest familiarizing yourself with the copyAll func here: https://github.com/ponzu-cms/ponzu/blob/master/cmd/ponzu/options.go#L334, as well as the various places it is called.. I think you'll probably want to use that when copying a go get package into ./addons - the build process should already account for anything added into ./addons, but it will be something you'll want to verify manually.

re: addon auto _ imports.. I agree that it feels odd, and maybe we simply document the Addon API in such a way that strongly suggests addon developers only run the addon.Register func in the addon package's init func - and nothing else (unless they know exactly how it will impact the system). I do plan on creating a generator for addons, much like content, so $ ponzu gen addon .... is a way to standardize this a bit.

If we can do that elegantly and practically, then I would feel much better about doing the auto _ import. Also, we will need to clearly document that the auto _ import only happens when using $ ponzu add ... so there is no expectation of it happening when someone simply copy/pastes a package into ./addons

[olliephillips]

Thanks, yes I'll look at this. My pleasure.

[nilslice]

Merged #87. Thank you!