Mongo Express container with Docker Compose

docker-compose.yml

Example container configuration:

    mongo-express:
        image: mongo-express
        container_name: mongo-express
        ports:
            - 8081:8081
        volumes:
            - ./.docker/mongo-express/docker-entrypoint.sh:/docker-entrypoint.sh
        env_file:
            - .env
        environment:
            ME_CONFIG_MONGODB_SERVER: mongodb
            ME_CONFIG_MONGODB_ADMINUSERNAME: ${MONGO_INITDB_ROOT_USERNAME}
            ME_CONFIG_MONGODB_ADMINPASSWORD: ${MONGO_INITDB_ROOT_PASSWORD}
            ME_CONFIG_BASICAUTH_USERNAME: ${ME_CONFIG_BASICAUTH_USERNAME}
            ME_CONFIG_BASICAUTH_PASSWORD: ${ME_CONFIG_BASICAUTH_PASSWORD}
        depends_on:
            - mongodb

What does it all mean?

        image: mongo-express

Specifies an image to use.

        container_name: mongo-express

Specifies a custom container name, rather than a generated default name.

        volumes:

Mounts host paths or named volumes, specified as sub-options to a service.

In case of the above configuration:

            - .docker/mongo-express/docker-entrypoint.sh:/docker-entrypoint.sh

will mount local .docker/mongo-express/docker-entrypoint.sh file as /docker-entrypoint.sh in the container, allowing easy modifications to the container initialization file.

This is a slightly modified original Mongo Express initialization script with only change being the modified value of max_tries=20 instead of original 5, to give the main mongodb container enough time to start and be connectable to.

        env_file:
            - .env

Add environment variables from a file. Can be a single value or a list.

        ports:
            - 8081:8081

Port mapping defined in short syntax: HOST:CONTAINER.

8081:8081 means that port 8081 on host will forward all its traffic to port 8081 in the container.

        environment:
            ME_CONFIG_MONGODB_SERVER: mongodb
            ME_CONFIG_MONGODB_ADMINUSERNAME: ${MONGO_INITDB_ROOT_USERNAME}
            ME_CONFIG_MONGODB_ADMINPASSWORD: ${MONGO_INITDB_ROOT_PASSWORD}
            ME_CONFIG_BASICAUTH_USERNAME: ${ME_CONFIG_BASICAUTH_USERNAME}
            ME_CONFIG_BASICAUTH_PASSWORD: ${ME_CONFIG_BASICAUTH_PASSWORD}

Add environment variables, either as an array or a dictionary.

        depends_on:
            - mongodb

Express dependency between services, so that they are started in the dependency order.

.docker/mongo-express/docker-entrypoint.sh

This is a slightly modified original Mongo Express initialization script with only change being the modified value of max_tries=20 instead of original 5, to give the main mongodb container enough time to start and be connectable to.

#!/bin/bash
set -eo pipefail

# This is a very small modification of the original docker script taken from
# https://github.com/mongo-express/mongo-express-docker/blob/master/docker-entrypoint.sh
# with only change being the modified value of max_tries=20 instead of original 5,
# to give the main mongodb container enough time to start and be connectable to.
# Also, see https://docs.docker.com/compose/startup-order/

# if command does not start with mongo-express, run the command instead of the entrypoint
if [ "${1}" != "mongo-express" ]; then
    exec "$@"
fi

function wait_tcp_port {
    local host="$1" port="$2"
    local max_tries=20 tries=1

    # see http://tldp.org/LDP/abs/html/devref1.html for description of this syntax.
    while ! exec 6<>/dev/tcp/$host/$port && [[ $tries -lt $max_tries ]]; do
        sleep 10s
        tries=$(( tries + 1 ))
        echo "$(date) retrying to connect to $host:$port ($tries/$max_tries)"
    done
    exec 6>&-
}

# if ME_CONFIG_MONGODB_SERVER has a comma in it, we're pointing to a replica set (https://github.com/mongo-express/mongo-express-docker/issues/21)
if [[ "$ME_CONFIG_MONGODB_SERVER" != *,* ]]; then
    # wait for the mongo server to be available
    echo Waiting for ${ME_CONFIG_MONGODB_SERVER}:${ME_CONFIG_MONGODB_PORT:-27017}...
    wait_tcp_port "${ME_CONFIG_MONGODB_SERVER}" "${ME_CONFIG_MONGODB_PORT:-27017}"
fi

# run mongo-express
exec node app

.env.dist

# Mongo Express
ME_CONFIG_BASICAUTH_USERNAME=admin
ME_CONFIG_BASICAUTH_PASSWORD=admin