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Dockerfile builds

Dockerfile builds allow you to build your application using a Dockerfile instead of the default Buildpacks. This is useful if you have a complex build process, or if you are already using Docker locally and want better parity between environments.

Requirements

Configuration with apppack.toml

At a minimum, you need to define your build system and services in apppack.toml. Here is an example of a simple apppack.toml file that uses Dockerfile builds and defines a single web service:

[build]
system = "dockerfile"

[services.web]
command = "npm start"

See the apppack.toml reference for more information.

Installed packages

Your final container must include the following commands so AppPack can run tools like shell:

  • bash
  • date
  • sh
  • sleep
  • pgrep
  • test

These are typically included in the base image you are using, but if you are using a minimal image, you may need to install them. How you install them depends on your base image, but usually they will come as part of bash, coreutils, and procps. To test if your image has these commands, you can run the following command:

# replace $YOUR_IMAGE with the name of your image
docker run --rm -it $YOUR_IMAGE /bin/sh -c 'for c in bash date sleep pgrep test; do command -v $c || echo ✘ $c MISSING; done'

If you see any commands flagged as MISSING, you'll need to install them to take full advantage of AppPack.

Here are some examples of installing the necessary commands for some common minimal images:

RUN apt-get update && apt-get install -y --no-install-recommends procps

RUN apk add --no-cache bash