Connecting to RabbitMQ container with docker-compose

Aha! I fixed it. @Ijaz was totally correct - the RabbitMQ service takes a while to start, and my worker tries to connect before it's running.

I tried using a delay, but this failed when the RabbitMQ took longer than usual.

This is also indicative of a larger architectural problem - what happens if the queuing service (RabbitMQ in my case) goes offline during production? Right now, my entire site fails. There needs to be some built-in redundancy and polling.

As described this this related answer, we can use healthchecks in docker-compose 3+:

version: "3"services:  rabbitmq:    image: rabbitmq    command: rabbitmq-server    expose:      - 5672      - 15672    healthcheck:      test: [ "CMD", "nc", "-z", "localhost", "5672" ]      interval: 5s      timeout: 15s      retries: 1  worker:    image: worker    restart: on-failure    depends_on:      - rabbitmq

Now, the worker container will restart a few times while the rabbitmq container stays unhealthy. rabbitmq immediately becomes healthy when nc -z localhost 5672 succeeds - i.e. when the queuing is live!

Maybe you dont need to expose/map the ports on the host if you are just accessing the service from another container.

From the documentation:

Expose Expose ports without publishing them to the host machine - they’ll only be accessible to linked services. Only the internal port can be specified.

expose: - "3000" - "8000"

So it should be like this:

version: "3"services:  rabbitmq:    image: rabbitmq    command: rabbitmq-server    expose:      - "5672"      - "15672"  worker:    build: ./worker    depends_on:      - rabbitmq    # Allow access to docker daemon    volumes:      - /var/run/docker.sock:/var/run/docker.sock

also make sure to connect to rabitmq only when its ready to server on port.

Here is the correct working example :

    version: "3.8"    services:    rabbitmq:        image: rabbitmq:3.7.28-management        #container_name: rabbitmq        volumes:            - ./etc/rabbitmq/conf:/etc/rabbitmq/            - ./etc/rabbitmq/data/:/var/lib/rabbitmq/            - ./etc/rabbitmq/logs/:/var/log/rabbitmq/        environment:            RABBITMQ_ERLANG_COOKIE: ${RABBITMQ_ERLANG_COOKIE:-secret_cookie}            RABBITMQ_DEFAULT_USER: ${RABBITMQ_DEFAULT_USER:-admin}            RABBITMQ_DEFAULT_PASS: ${RABBITMQ_DEFAULT_PASS:-admin}        ports:            - 5672:5672    #amqp            - 15672:15672  #http            - 15692:15692  #prometheus        healthcheck:        test: [ "CMD", "rabbitmqctl", "status"]        interval: 5s        timeout: 20s        retries: 5    mysql:        image: mysql        restart: always        volumes:        - ./etc/mysql/data:/var/lib/mysql        - ./etc/mysql/scripts:/docker-entrypoint-initdb.d        environment:        MYSQL_ROOT_PASSWORD: root        MYSQL_DATABASE: mysqldb        MYSQL_USER: ${MYSQL_DEFAULT_USER:-testuser}        MYSQL_PASSWORD: ${MYSQL_DEFAULT_PASSWORD:-testuser}        ports:        - "3306:3306"        healthcheck:        test: ["CMD", "mysqladmin" ,"ping", "-h", "localhost"]        timeout: 20s        retries: 10    trigger-batch-process-job:        build: .        environment:        - RMQ_USER=${RABBITMQ_DEFAULT_USER:-admin}        - RMQ_PASS=${RABBITMQ_DEFAULT_PASS:-admin}        - RMQ_HOST=${RABBITMQ_DEFAULT_HOST:-rabbitmq}        - RMQ_PORT=${RABBITMQ_DEFAULT_PORT:-5672}        - DB_USER=${MYSQL_DEFAULT_USER:-testuser}        - DB_PASS=${MYSQL_DEFAULT_PASSWORD:-testuser}        - DB_SERVER=mysql        - DB_NAME=mysqldb        - DB_PORT=3306        depends_on:        mysql:            condition: service_healthy        rabbitmq:            condition: service_healthy