Redis + Docker: PDOException: could not find driver

Question

I'm new to using Redis. I'm running Laravel, MariaDB, and Redis in Docker. I can't seem to get redis to work properly. I get the following error in Laravel Horizon:

PDOException: could not find driver in /var/www/api/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php:46

My guess is that the code is being executed inside the redis container, that has no access to the PHP container.

This is my docker-compose.yml:

# Web server
nginx:
    image: nginx:latest
    restart: always
    links:
    - socketio-server
    ports:
    - "3000:3001"
    - "8081:80"
    volumes:
    - ./api:/var/www/api
    - ./docker/nginx/conf.d/:/etc/nginx/conf.d
    - ./docker/nginx/nginx.conf:/etc/nginx/nginx.conf
    links:
    - php

# PHP
php:
    build: ./docker/php-fpm
    volumes:
    - ./api:/var/www/api
    links:
    - mariadb

# Redis
redis:
    image: redis:latest
    depends_on:
    - php
    expose:
    - "6379"

# Database
mariadb:
    image: mariadb:latest
    restart: always
    ports:
    - "3306:3306"
    volumes:
    - ./database/mariadb/:/var/lib/mysql

# PHP workers
php-worker:
    build:
    context: ./docker/php-worker
    args:
        - PHP_VERSION=7.2
        - INSTALL_PGSQL=false
    volumes:
    - ./:/var/www
    - ./docker/php-worker/supervisor.d:/etc/supervisor.d
    extra_hosts:
    - "dockerhost:10.0.75.1"
    links:
    - redis

Anyone any ideas?

Answer 1

I turned out to be a problem in the 'php-worker' container. I hadn't installed pdo_mysql here. Now everything works fine!

Answer 2

Your assumption that the containers don't have access to each other is correct.

Your PHP container executes the PHP code, so it must have access to the redis container and the mariadb container in order to use them. You do this by adding them to the links array. I see you have already done this for mariadb, but you should add redis as well.

# PHP
php:
    build: ./docker/php-fpm
    volumes:
    - ./api:/var/www/api
    links:
    - mariadb
    - redis

By adding redis to the links array, you can access it in your PHP container with the hostname redis.