Docker and PHP

Contents of a Docker directory

The following files must be present to use docker-compose:

docker-compose.yml
Dockerfile

docker-compose build will build the image.

Run a basic PHP Docker image

docker run --rm php:7.4-apache-buster php --version

The --rm argument removes the container after it has finished.

Basic PHP Dockerfile

Build an image and copy in a PHP file:

FROM php:7.4-apache-buster

COPY index.php /var/www/html/

To build the image:

docker build -t phpinfo:latest .

To run the image:

docker run --rm -p 8080:80 phpinfo

Basic PHP Docker Compose

version: "3"
services:
  app:
    image: phpinfo
    container_name: phpinfo
    build:
      context: .
      dockerfile: docker/Dockerfile
    ports:
      - 8080:80

This can be built and run with:

docker-compose up --build -d

-d runs the container as a daemon, and returns the command line immediately.

Dockerfile doesn't have to be in a different directory, but this seems to be something of a convention and perhaps keeps things tidy. By default docker-compose will look for a Dockerfile in the current directory.

Database

Assuming you want to use MariaDB:

version: "3"
services:
    app:
        build: .
        ports:
            - 8080:80
   
    database:
        image: mariadb
        restart: always
        environment: 
            MARIADB_RANDOM_ROOT_PASSWORD: "yes"
            MARIADB_DATABASE: app
            MARIADB_USER: app
            MARIADB_PASSWORD: secret
        ports:
            - 3307:3306

Extensions

PHP extensions can be installed via docker-php-ext-install, e.g. to install the MySQL extension:

RUN docker-php-ext-install pdo_mysql