How to use docker with drupal and drush?

I have spent way too much time getting this to work. Here are my findings.

Like OP I never got the drush image to work on the local docker network so it seemed simpler to me to bundle drush via composer with the drupal image (see Dockerfile below).

That works somewhat, if you exec into the container you can run drush status, but it won't connect to the mysql server. There are two reasons for this:

1. The package mysql-client is needed to connect remotely to the database (since we are running this on a local docker network).

2. The mysql hostname needs to be explicitly set in the docker-compose file (or docker run command).

This is my Dockerfile:

FROM drupal:8.3.7-apache# Install packagesRUN rm /bin/sh && ln -s /bin/bash /bin/sh && \    apt-get update && apt-get install --no-install-recommends -y \    curl \    wget \    vim \    git \    unzip \    mysql-client# Install ComposerRUN curl -sS https://getcomposer.org/installer | php && \    mv composer.phar /usr/local/bin/composer && \    ln -s /root/.composer/vendor/bin/drush /usr/local/bin/drush# Install DrushRUN composer global require drush/drush && \    composer global update# Clean repositoryRUN apt-get clean && rm -rf /var/lib/apt/lists/*

The important packages are curl (obviously) and mysql-client.

And these are the relevant parts of the docker-compose.yml:

version: '3.3'services:  drupal:    image: drupal    build: ./docker/drupal    env_file:      - ./docker/environment.env    ports:      - "8080:80"    depends_on:      - mysql    restart: always  phpmyadmin:    image: phpmyadmin/phpmyadmin:latest    volumes:      - ./docker/phpmyadmin/config.user.inc.php:/etc/phpmyadmin/config.user.inc.php    env_file:      - ./docker/intervention/environment.env    ports:      - "8080:80"    depends_on:      - mysql    restart: always  mysql:    image: mysql    build: ./docker/mysql    env_file:      - ./docker/environment.env    hostname: mysql    ports:      - 3306:3306    volumes:      - mysql-data-d8:/var/lib/mysql    restart: alwaysvolumes:  mysql-data-d8:

Why explicitly setting the hostname works

The second problem above is particularly devilish since drush use the configuration from settings.php to connect to mysql. But the 'host' key in the databases array is interpreted differently by drupal and drush apparently. Here is the relevant section from settings.php:

$databases = array (  'default' => array (    'default' => array (      'database' => $envs['MYSQL_DATABASE'] ?? '',      'username' => $envs['MYSQL_USER'] ?? '',      'password' => $envs['MYSQL_PASSWORD'] ?? '',      'host' => 'mysql',//php_sapi_name() === 'cli' ? 'a8597b38be21' : 'mysql',      'port' => '3306',      'driver' => 'mysql',      'prefix' => 'drupal_',      'charset' => 'utf8mb4',      'collation' => 'utf8mb4_general_ci',      'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',    ),  ),);

The out commented line after 'host' => 'mysql' is a previous attempt taken from another SO answer and illustrates the problem, drush use the command line server API which is different from whatever drupal uses. The alternate hostname is the hash id of the running container, which can be found by running the sql (from phpmyadmin for example):

SHOW VARIABLES WHERE Variable_name = 'hostname' (taken form this)

This value changes every time the container is updated, so to make it persist, the hostname is explicitely stated in docker-compose.yml, se above.

Edit: I've made a small project to host a drupal + drush + phpmyadmin development environment based on this: https://github.com/glaux/drupal8docker

As always with Docker there are many options to use drush. But notice that in order drush to have access to the database (eg mysql) there should be volumes from mysql container on Drupal such as:

 version: '2' services:   drupal:     image: drupal:8.0.4-apache     volumes_from:       - mysql   mysql:     image: mysql     volumes:       - /var/lib/mysql       - /usr/bin...

Here are the most common.

1) Mount your local drush to the Drupal container:

version: '2'services:  drupal:    image: drupal:8.0.4-apache    volumes:      # Mount local drush to your container.      - /usr/local/bin/drush:/drush/drush

2) Create a data only docker image for drush and volume the executable to your Drupal container. See an example at https://github.com/RobLoach/drush-docker/issues/32#issuecomment-222321265.

3) Install Drush into Drupal container after it has run. Eg:

$ docker exec -ti <MY_DRUPAL_CONTAINER> \ bash -c 'php -r "readfile('https://s3.amazonaws.com/files.drush.org/drush.phar');" \> drush  && chmod +x drush && mv drush /usr/local/bin'

4) Install Drush on Drupal by creating a Docker image (using a Dockerfile). Example:

FROM drupal:8.0.4-apacheMAINTAINER ...RUN php -r "readfile('https://s3.amazonaws.com/files.drush.org/drush.phar');" > drush \&& chmod +x drush \&& mv drush /usr/local/bin

5) Use another container with drush and volume it to the Drupal container using the docker-compose.yml. Example:

version: '2'services:  drupal:    image: drupal:8.0.4-apache    volumes_from:      - drush  drush:    image: drush/drush    volumes:      - /usr/local/bin/drush      - /usr/local/bin/composer

In order to make Drush work effectively - you're better off running it from within the container that is running Drupal. For that, add a one liner in your Dockerfile.

# Set base Image/tag here. FROM drupal:8-fpm # Get a global installation of Drush on the web / drupal container RUN php -r "readfile('http://files.drush.org/drush.phar');" > drush && chmod +x drush && mv drush /usr/bin/

For actual usage, you're better off shipping separate Drush aliases for usage - both from the container and the host (via public key SSH). As an example, look at these aliases and consider the entire setup as a reference implementation: https://github.com/srijanaravali/docker-blueprint/blob/master/docker-utils/drush/local.aliases.drushrc.php

You can transport these aliases into the container by having something like this in your Dockerfile:

# Push our aliases into the container ~/.drush ADD /path/to/your/drush-aliases/* ~/.drush/

or - for shared control with the host, you can consider having it mounted as a volume in your docker-compose.yml.

volumes:  - ~/.drush/:/root/.drush/

You can now run Drush commands on the container like this: docker exec drush @alias <command>. You can bash alias that to be something less keyboard intensive, ofcourse.

Or, Use drush from your host by invoking the SSH alias you shipped instead - drush @alias-ssh <command>