by weibeld

GitHub Readme.md

Heroku Buildpack: Run

Run custom commands during the build process.


This buildpack allows to specify arbitrary commands that will be run in sequence during the build process.

If any command exits with a non-zero code, the build is aborted.


Add the buildpack in addition to any other buildpacks:

heroku buildpacks:add https://github.com/weibeld/heroku-buildpack-run

Set the buildpack as the only buildpack:

heroku buildpacks:set https://github.com/weibeld/heroku-buildpack-run


The commands to run are specified in the BUILDPACK_RUN config variable by using colons as delimiters.

A command can be anything from a user-provided shell script or binary to a native UNIX command. Commands may have arguments as well.

All commands must be executable. That means, shell scripts must have a shebang line (#!/bin/bash or similar) and must have the executable bit set (run chmod +x script.sh on your local machine, then commit and push as usual).


heroku config:set BUILDPACK_RUN='./script.sh:ls -l:bin/myexec foo bar'
git push heroku master

This causes the buildpack to run the following commands in sequence:

  1. ./script.sh
  2. ls -l
  3. bin/myexec foo bar


  • ./script.sh is a user-provided shell script
  • ls -l refers to the native ls command on the build dyno
  • bin/myexec is a user-provided binary

Default value

If the BUILDPACK_RUN config variable is unset, then ./buildpack-run.sh is used as the default command.

So, if you want to run only a shell script, you can name it buildpack-run.sh and omit setting the BUILDPACK_RUN config variable.

Don't forget to make the script executable by running chmod +x buildpack-run.sh on your local machine, then commit and push as usual.

Environment variables

The following special environment variables are available to your commands during the build:

  • BUILD_DIR: absolute path of your app's root directory on the build dyno
  • CACHE_DIR: cache directory that persists between builds
  • ENV_DIR: directory containing the values of all config variables in files

BUILD_DIR corresponds to the working directory during the execution of the buildpack.


Licensed under the MIT License. See LICENSE.md file.