Support post compile hook

[chrismccord]

For Phoenix, we would like to have a complete buildpack solution when we ship 1.0, which means we need to be able to build brunch assets after compile. I'm not sure where to start here, but @ericmj has some idea where we need to begin.

[HashNuke]

@chrismccord won't that mean we would need node.js installed too? (https://github.com/ddollar/heroku-buildpack-multi).

\cc: @ericmj

[rwdaigle]

Just an FYI that Heroku Buildpacks have changed a bit. You no longer need the multi-buildpack to specify a build pipeline. Instead, specify each buildpack individually with the following CLI:

$ heroku buildpacks:set https://github.com/HashNuke/heroku-buildpack-elixir.git
$ heroku buildpacks:set https://github.com/heroku/heroku-buildpack-nodejs

Regarding brunch asset compilation, here's how they do it in the official Ruby/Rails buildpack.

[ericmj]

Should we automatically run a post_compile / post_compile.sh file in your root directory or should we take the file from a post_compile option in elixir_buildpack.config?

/cc @josevalim

[josevalim]

I thought the plan was to not support hooks. What changed? :)

[HashNuke]

At work, I was working with a non-Heroku deployed app where the compilers option in mix.exs was used to add a :frontend compiler so that everytime the app is started or compiled, the frontend too gets compiled.

Curious how a post compile hook will help on Heroku since we depend on mutl-buildpack for asset compilation.

[ericmj]

At work, I was working with a non-Heroku deployed app where the compilers option in mix.exs was used to add a :frontend compiler so that everytime the app is started or compiled, the frontend too gets compiled.

The problem is that you might not want to compile assets on every compilation or app start so a Heroku specific compilation step is very useful.

Curious how a post compile hook will help on Heroku since we depend on mutl-buildpack for asset compilation.

Not sure what you are asking here, as long as the node buildpack runs before the elixir buildpack it will work.

[HashNuke]

@ericmj I meant to ask what the use case was for the post-compile hook. I remember there was this discussion earlier in another issue and that that issue was closed.

Sorry read your comment in bed and forgot to reply the other day.

[ericmj]

phoenixframework/phoenix#835

[HashNuke]

@ericmj 👍 thanks for linking. Got it now ~!

[HashNuke]

Yaaay ~!