How to pass arguments within docker-compose?

Docker 1.9 allows to pass arguments to a dockerfile. See link: https://docs.docker.com/engine/reference/builder/#arg

How can I pass the same arguments within docker-compose.yml?
Please provide an example too, if possible.

Solution 1:

Now docker-compose supports variable substitution.

Compose uses the variable values from the shell environment in which docker-compose is run. For example, suppose the shell contains POSTGRES_VERSION=9.3 and you supply this configuration in your docker-compose.yml file:

db:
  image: "postgres:${POSTGRES_VERSION}"

When you run docker-compose up with this configuration, Compose looks for the POSTGRES_VERSION environment variable in the shell and substitutes its value in. For this example, Compose resolves the image to postgres:9.3 before running the configuration.

Solution 2:

This can now be done as of docker-compose v2+ as part of the build object;

docker-compose.yml

version: '2'
services:
    my_image_name:
        build:
            context: . #current dir as build context
            args:
                var1: 1
                var2: c

See the docker compose docs.

In the above example "var1" and "var2" will be sent to the build environment.

Note: any env variables (specified by using the environment block) which have the same name as args variable(s) will override that variable.

Solution 3:

This feature was added in Compose file format 1.6.

Reference: https://docs.docker.com/compose/compose-file/#args

services:
  web:
    build:
      context: .
      args:
        FOO: foo

Solution 4:

Something to add to these answers that the args are picked up only when using docker-compose up --build and not when using docker-compose build. If you want to build and run in separate steps, you need use docker-compose build --build-arg YOUR_ENV_VAR=${YOUR_ENV_VAR}or docker build --build-arg YOUR_ENV_VAR=${YOUR_ENV_VAR}

Solution 5:

1. Create a variable environment on Linux shell:

   export TAG=0.1.2
   

2. Set variable inside docker-compose.yml

   db:
     image: "redis:${TAG}"
   

3. Verify if value was replaced

   docker-compose config