Docker-Compose: Different Build Context Path and Dockerfile File Path

I was writing an application and I had to dockerize it.

I wrote a Dockerfile to build my application and run it. Things were OK when I ran it using docker command alone.

But I had to run the application using docker-compose. I wrote a docker-compose.yml file to build as well as run the application. Here I am going to show only a simple application for the demonstration. Following is my Dockerfile content.

FROM golang:alpine
ADD code/hello.go /code/
WORKDIR /
CMD [“go”, “run”, “code/hello.go”]

hello.go is simple echo program that will print hello world. Location of hello.go is /workspace/docker-helloworld/code and of Dockerfile is /workspace/docker-helloworld/docker.

workspace
   |- docker-helloworld
       |- code
           |- hello.go
       |- docker
           |- Dockerfile

As you see, Dockerfile and my application are at different location. Build Context for my application will be /workspace/docker-helloworld while the location of Dockerfile is in different directory.

Fortunately, docker-compose allow us to define separate build context path and Dockerfile file path. Follow is definition of my docker-compose entry:

helloworld:
  build:
    context: /workspace/docker-helloworld
    dockerfile: /workspace/docker-helloworld/docker/Dockerfile
  image: hello-world