Communicating between ros services in docker-compose

[nicholasadr]

Sometimes it might be desirable to run multiple ros nodes in separate docker containers. The following docker-compose file shows how we can do so.

Some note:

• There are two separate Dockerfiles for each service (ros-server and ros-client) contained in separate directory ./server/ and ./client/ as indicated in context
• We created a custom network in order to assign static IPs to each container. This way, we can assign $ROS_IPs and point client's $ROS_MASTER_URI towards the server's IP that will start the rosmaster
• In this case the ros server runs a Deep Learning server

docker-compose.yml example:

version: '2.3'
services:
  ros-server:
    networks:
      ros-network:
        ipv4_address: ${dSERVER_IP}
    image: ros-server:v1.0.0
    build:
      context: ./server
      args:
        user: ${dUSER}
        group: ${dGROUP}
        uid: ${dUID}
        gid: ${dGID}
    environment:
      - "ROS_IP=${dSERVER_IP}"
    user: "${dUID?err}:${dGID?err}"
    runtime: nvidia
    tty: true
    ports:
    - "${dJUPYTER_PORT?err}:8888"
    - "${dTENSORBOARD_PORT?err}:6006"
    volumes:
    - "${dDRIVE?err}:/data"
    - "${dWORKSPACE?err}:/home/${dUSER}/workspace"
  ros-client:
    networks:
      ros-network:
        ipv4_address: ${dCLIENT_IP}
    image: ros-client:v1.0.0
    build:
      context: ./client
      args:
        user: ${dUSER}
        group: ${dGROUP}
        uid: ${dUID}
        gid: ${dGID}
    environment:
      - "ROS_IP=${dCLIENT_IP}"
      - "ROS_MASTER_URI=http://${dSERVER_IP}:11311"
    user: "${dUID?err}:${dGID?err}"
    runtime: nvidia
    tty: true
    volumes:
    - "${dDRIVE?err}:/data"
    - "${dWORKSPACE?err}:/home/${dUSER}/workspace"

networks:
  ros-network:
    driver: bridge
    ipam:
      config:
        - subnet: 10.5.0.0/16
          gateway: 10.5.0.1

.env contains:

dSERVER_IP=10.5.0.5
dCLIENT_IP=10.5.0.6

References:

• https://stackoverflow.com/questions/39493490/provide-static-ip-to-docker-containers-via-docker-compose
• https://docs.docker.com/compose/networking/
• https://answers.ros.org/question/228292/exposing-ros-containers-to-host-machine/