Buildpacks should generally just work, but many of them make assumptions about their environment. So Buildstep has a list of officially supported buildpacks that are built-in and ready to be used.
The buildstep script uses a buildstep base container that needs to be built. It must be created before
you can use the buildstep script. To create it, run:
$ docker build -t buildstep .
This will create a container called
progrium/buildstep that contains all supported buildpacks and the
builder script that will actually perform the build using the buildpacks.
Building an App
Running the buildstep script will take an application tar via STDIN and an application container name as
an argument. It will put the application in a new container based on
progrium/buildstep with the specified name.
Then it runs the builder script inside the container.
$ cat myapp.tar | ./buildstep myapp
If you didn't already have an application tar, you can create one on the fly.
$ tar cC /path/to/your/app . | ./buildstep myapp
The resulting container has a built app ready to go. The builder script also parses the Procfile and produces
a starter script that takes a process type. Run your app with:
$ docker run -d myapp /bin/bash -c "/start web"
Buildstep needs to support a buildpack by installing packages needed to run the build and to run the application
it builds. For example, the Python buildpack would need Python to be installed.
To add a new buildpack to buildstep, add commands to install the necessary packages that the buildpack and built
application environment will need to stack/packages.txt and stack/prepare. Then add the buildpack Git URL to the file stack/buildpacks.txt
You'll then have to re-build.