Docker – Nginx, PHP, MySQL – Laravel artisan migrate connection refused

I have Laravel running in Docker with 3 containers – Nginx, MySQL 8 And PHP 8.

I have the following docker-compose.yaml

version: '3.8'

services: 
  server:
    build:
      context: .
      dockerfile: dockerfiles/nginx.dockerfile
    ports: 
      - '8000:80'
    volumes: 
      - ./src:/var/www/html
      - ./nginx/nginx.conf:/etc/nginx/conf.d/default.conf:ro
    container_name: server
    depends_on: 
      - app
      - db
  app:
    build:
      context: .
      dockerfile: dockerfiles/php.dockerfile
    volumes: 
      - ./src:/var/www/html:delegated
    container_name: app
  db:
    image: mysql:8.0
    env_file: 
      - ./env/mysql.env
    container_name: db

This command:

docker-compose up -d server

Launches 3 containers:

CONTAINER ID   IMAGE                COMMAND                  CREATED          STATUS         PORTS                  NAMES
5ff5cbefd12e   toolkit_server   "/docker-entrypoint.…"   9 seconds ago    Up 3 seconds   0.0.0.0:8000->80/tcp   server
c7f3c9753909   toolkit_app      "docker-php-entrypoi…"   14 seconds ago   Up 8 seconds   9000/tcp               app
d7b421bd3c3b   mysql:8.0        "docker-entrypoint.s…"   14 seconds ago   Up 9 seconds   3306/tcp, 33060/tcp    db

I want to run php artisan migrate, so I try it like so:

docker-compose exec app php artisan migrate

This gives me the following error:

 IlluminateDatabaseQueryException 
 SQLSTATE[HY000] [2002] Connection refused (SQL: select * from information_schema.tables where table_schema = toolkit and table_name = migrations and table_type = 'BASE TABLE')

My mysql.env file is like so:

MYSQL_DATABASE=toolkit
MYSQL_USER=root
MYSQL_PASSWORD=password
MYSQL_ROOT_PASSWORD=password

AND .env:

DB_CONNECTION=mysql
DB_HOST=db
DB_PORT=3306
DB_DATABASE=toolkit
DB_USERNAME=root
DB_PASSWORD=password

I’ve tried changing ports, host, but I just can’t get access – I must have messed something up somewhere.