by glmaljkovich


Reaction Commerce Buildpack

This buildpack is a fork of meteor-buildpack-horse with our modifications to ease deployment and overcome common failures (like boot timeout).

To use this with heroku:

  1. Set up your app to deploy to heroku with git.

  2. Set this repository as the buildpack URL:

     heroku buildpacks:set
  3. Add the MongoLab addon:

     heroku addons:create mongolab
  4. Set the ROOT_URL environment variable. This is required for bundling and running the app. Either define it explicitly, or enable the Dyno Metadata labs addon to default to https://<appname>

     heroku config:set ROOT_URL="https://<appname>" # or other URL

Once that's done, you can deploy your app using this build pack any time by pushing to heroku:

git push heroku master


The following are some important environment variables for bundling and running your meteor app on heroku. Depending on your settings, you may need to override these on heroku. See heroku's documentation for how to set these.

  • ROOT_URL: The root URL for your app, needed for bundling as well as running. If you enable the Dyno Metadata labs addon and ROOT_URL is undefined, it will default to https://<appname>
  • MONGO_URL: The URL to mongodb. It not defined, it will default the value of MONGODB_URI, MONGOLAB_URI, or MONGOHQ_URL (in order). If you don't use mongolab as a regular addon (and none of the fallbacks are defined), you'll need to set this.
  • METEOR_APP_DIR: The relative path to the root of your meteor app within your git repository (i.e. the path to the directory that contains .meteor/). The buildpack will look in the root of your repository and app/ subdirectory; if you put your app anywhere else (like src/), define this variable to tell the buildpack where to look.
  • BUILDPACK_PRELAUNCH_REACTION: If your app uses packages that need to compile their assets on first run, you may need reaction to launch prior to bundling. If this applies for you, define BUILDPACK_PRELAUNCH_REACTION=1. Reference issue.
  • REACTION_TIMEOUT: If BUILDPACK_PRELAUNCH_REACTION is set wait for this many seconds before killing Reaction. Defaults to 600 (10 minutes).
  • BUILDPACK_VERBOSE: Set BUILDPACK_VERBOSE=1 to enable verbose bash debugging during slug compilation. Only takes effect after the environment variables have been loaded.
  • BUILDPACK_CLEAR_CACHE: This buildpack stores the meteor installation in the CACHE_DIR to speed up subsequent builds. Set BUILDPACK_CLEAR_CACHE=1 to clear this cache on startup.
  • BUILD_OPTIONS: Set to any additional options you'd like to add to the invocation of meteor build, for example --debug or --allow-incompatible-update.

Boot proxy

Sometimes reaction takes too much time to start and Heroku thinks that there's a problem with your app. To sidestep this we have a simple proxy that answers every request until it's ready.

It accepts the following environment variables:

  • USE_BOOT_PROXY: Set USE_BOOT_PROXY=1 to enable it. It's disabled by default.
  • PING_PATH: The route we use to test if your app is ready. Defaults to /. You need to add a leading slash.
  • PING_INTERVAL: Interval between probes, in seconds. Defaults to 1 second.
  • BOOT_TIMEOUT: Maximum time to wait for your app in seconds. Defaults to 3600 (1 Hour). If reached we exit with an error.
  • BOOTING_URL: Proxies transparently to this url while your app is booting if provided.


The basic buildpack should function correctly for any normal-ish meteor app, with or without npm-container. For extra steps needed for your particular build, just add shell scripts to the extra folder and they will get sourced into the build.

Extras included in this branch:

  • If MONGO_URL is empty, set it to the value of MONGODB_URI, MONGOLAB_URI, or MONGOHQ_URL (in order).
  • If ROOT_URL is empty and HEROKU_APP_NAME is available, set ROOT_URL to https://$

Where things go

This buildpack creates a directory .meteor/heroku_build ($COMPILE_DIR) inside the app checkout, and puts all the binaries and the built app in there. So it ends up having the usual unixy bin/, lib/, share etc subdirectories. Those directories are added to $PATH and $LD_LIBRARY_PATH appropriately.

So $COMPILE_DIR/bin etc are great places to put any extra binaries or stuff if you need to in custom extras.