docker-compose.yml - make network name configurable via environment variable

Question

I have a docker compose file with env variables for stage specific configurations. As long as env variables are used in values in docker-compose.yml everything is fine, but the problem is with the network name, since it's specified in the tag.

networks:
  mynetwork.${STAGE_NAME}:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: ${STAGE_NETWORK_PREFIX}.0/24

Any chance to get the network name mynetwork.${STAGE_NAME} configurable from outside?

Answer 1

If you have envsubst installed (part or gnu gettext) you can use something like that:

export STAGE_NAME="xyz"
export STAGE_NETWORK_PREFIX="1.2.3.4"
docker-compose -f <(envsubst docker-compose.yml) ...

If your shell does not support process substitution, something like that would do the trick:

envsubst docker-compose.yml | docker-compose -f - ...

Answer 2

It is possible via network name:

networks:
  mynetwork:
    name: ${STAGE_NAME}

where mynetwork - name "inside" stack

${STAGE_NAME} -name for other stacks/services/containers

See comment from docker capitan https://github.com/moby/moby/issues/40819#issuecomment-618726892

Answer 3

I didn't find a way to directly control this, but I noticed that the folder containing the docker-compose.yml is used as prefix when creating the name for the docker network. My solution was to write a wrapper script for docker-compose which creates a new folder with the name of the stage

TARGET=/tmp/$STAGE_NAME

mkdir -p $TARGET

ln -sf $(pwd)/docker-compose.yml $TARGET/docker-compose.yml

cd $TARGET
docker-compose "$@"
cd -

Answer 4

There is a switch -p in docker-compose which allow you to set this prefix to a custom value.