MonorepoExample

Building independent images from a monorepo

Please note this umbrella project / repo defines two releases:

  defp releases do
    [
      service_c: ...,
      service_d: ...
    ]
  end

And a Dockerfile flexible enough to containerize each release independently.

Building a release container image:

docker buildx build --build-arg MONOREPO_SERVICE=<release-name> -t <release-container-tag> .

For example:

docker buildx build --build-arg MONOREPO_SERVICE=service_c -t monorepo_service_c:latest .
docker buildx build --build-arg MONOREPO_SERVICE=service_d -t monorepo_service_d:latest .

We can also use the alias defined in mix.exs to build all the release container images defined in this repo:

mix docker.build

Check out config/runtime.exs and Direnv .envrc to see how to achieve independent configuration of each of the release containers.

How can we tell that two distinct releases were actually built?

$ docker run --rm -it \
  --env MONOREPO_SERVICE=service_c \
  --env MONOREPO_SERVICE_C_OPTION=${MONOREPO_SERVICE_C_OPTION} \
  docker.io/library/monorepo_service_c:latest start_iex
Erlang/OTP 25 [erts-13.2.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]

Interactive Elixir (1.13.4) - press Ctrl+C to exit (type h() ENTER for help)
iex(service_c@63ce91c04b00)1> Application.started_applications()
[
  ...
  {:service_c, 'service_c', '0.1.0'},
  {:lib_a, 'lib_a', '0.1.0'},
  ...
]
iex(service_c@63ce91c04b00)2> Application.get_all_env(:service_c)
[service_c_option: "service-c-val"]
iex(service_c@63ce91c04b00)2> Application.get_all_env(:service_d)
[]

$ docker run --rm -it \
  --env MONOREPO_SERVICE=service_d \
  --env MONOREPO_SERVICE_D_OPTION=${MONOREPO_SERVICE_D_OPTION} \
  docker.io/library/monorepo_service_d:latest start_iex
Erlang/OTP 25 [erts-13.2.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]

Interactive Elixir (1.13.4) - press Ctrl+C to exit (type h() ENTER for help)
iex(service_d@6573325de339)1> Application.started_applications()
[
  ...
  {:service_d, 'service_d', '0.1.0'},
  {:lib_b, 'lib_b', '0.1.0'},
  ...
]
iex(service_d@6573325de339)1> Application.get_all_env(:service_c)
[]
iex(service_d@6573325de339)1> Application.get_all_env(:service_d)
[service_d_option: "service-d-val"]

erszcz/monorepo-example

MonorepoExample

Building independent images from a monorepo