“Deploying to Heroku” by John Barnette

Deploying to Heroku with git push is awesome. I’m running a couple of different environments, though, and there’s extra stuff that I want to do when I deploy. Rake to the rescue!

Some Assumptions

Okay, here’s how I roll: origin is GitHub. origin/master is the production branch, not the head of development. origin/next is, well, what’s next (you probably call it “staging”). There are local tracking branches for each of these, natch.

New features happen in topic branches, and they’re merged into next when they’re ready. Emergencies and bug fixes are similar, but they also get merged into master and deployed before next is fully baked.

master is only ever updated by bug/emergency branch merges and periodic merges of next. If git merge next isn’t a fast-forward, something’s probably wrong.

There are (at the moment) two Heroku environments, myapp-next and myapp-master. There’s a Git remote for each environment:

$ git remote
heroku-next
origin
heroku-master

Got it? Good.

Deploying

$ rake deploy

Super complicated. In my setup, this task…

Complains if I’m trying to deploy from a branch that doesn’t match an deployment env (deploys can only happen from master and next),
sets the TO environment variable for Hoptoad,
shows a list of all the changes since the last deploy, and how long it’s been,
pushes the current branch to the matching remote, e.g., git push heroku-next next:master,
tells Hoptoad about the deploy, and
sends a fancy email w/changes to the deployment mailing list.

The First Time

$ rake deploy:newb

This task installs the heroku and taps gems if they’re not available, creates and fetches the Heroku remotes for each environment, and makes sure you have local tracking branches for the origin/bleh equivalents of each remote.

What changed?

$ rake deploy:pending

This task shows a list of commits that have happened since the last deploy. It’s a pretty thin wrapper around git log.

I Hate Conclusions

There are a few other lifecycle hooks for attaching stuff that needs to happen before or after the deploy, but that’s pretty much it. A lightly edited version of my lib/tasks/deploy.rake is available in this Gist. Add to it, correct it, abuse it.