Can I use Docker Compose with images that use the builder-pattern?

Question

I'm aware of the new multi-stage build feature, which works nicely with Docker Compose. However, let's say I'm stuck with the builder-pattern (don't ask)... is there any way to have docker-compose up use the build script required by the builder pattern?

Consider the same builder-pattern files from the linked article:

Dockerfile.build

FROM golang:1.7.3
WORKDIR /go/src/github.com/alexellis/href-counter/
RUN go get -d -v golang.org/x/net/html  
COPY app.go .
RUN go get -d -v golang.org/x/net/html \
  && CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .

Dockerfile

FROM alpine:latest  
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY app .
CMD ["./app"]

build.sh

#!/bin/sh
docker build -t alexellis2/href-counter:build . -f Dockerfile.build

docker create --name extract alexellis2/href-counter:build  
docker cp extract:/go/src/github.com/alexellis/href-counter/app ./app  
docker rm -f extract

docker build --no-cache -t alexellis2/href-counter:latest .
rm ./app

I could construct a Docker Compose file kinda like this one, but I have no idea how to cp the files from the temporary Docker container.

docker-compose.yml

version: '3'
services:
  app: 
    build: .
    depends_on:
     - app-build
  app-build:
    build:
      context: .
      dockerfile: Dockerfile.build

I could build the temporary Docker image/container and run the cp by using the first part of the build.sh script from above and then using a stripped down compose file, but, then, I might as well just stick with the script.

Answer 1

An approach can be using 2 docker-compose calls, combined with a directory mapping:

version: '3'
services:
  app: 
    build: .

  app-build:
    build:
      context: .
      dockerfile: Dockerfile.build
    volumes:
       - ./build/:/go/src/github.com/alexellis/href-counter/

Then:

#This will produce local ./build/app artifact
docker-compose build app-build

#Having the previous artifact, will use it:
docker-compose build app

Just change this into Dockerfile:

COPY build/app .

However, I recommend you the Multi Stage Build approach. Hugely simpler than this.

Answer 2

As I understood, you are asking if it is possible to use something like docker cp within the compose file to extract an artifact from the temporary container.

Well, using a shared volume is an option for that.

version: '3'
    services:
      app: 
        build: .
        depends_on:
         - app-build
        volumes:
        - shared:/source        
      app-build:
        build:
          context: .
          dockerfile: Dockerfile.build
        volumes:
        - shared:/output
    volumes:
      - shared:

But you have to add a script in app service which will check if app-build has finished its work and the artifact is ready.

Using shared volumes is a bit risky. You must know what you are doing.

Multiple containers can also share one or more data volumes. However, multiple containers writing to a single shared volume can cause data corruption. https://docs.docker.com/engine/tutorials/dockervolumes/#important-tips-on-using-shared-volumes

There is an issue titled "Add copy to the yaml configuration" on github: https://github.com/docker/compose/issues/1664

I would like to have an option like that in compose file. You can check others' opinions about this on the link above. That issue is closed now but might be opened again.