What I learned building a development environment in Docker

Because I recently switched to working on an M1 Macbook, I could no longer rely on my Homestead-driven development environment. I have now switched to a newly created setup that runs on Docker instead.

My setup runs the following services:

  • Nginx - webserver.
  • PHP - to serve all PHP requests. Also contains NodeJS to compile css and javascript assets.
  • MySQL - database server.
  • Redis - for caching and session storage.
  • Maildev - for testing emails locally.
  • Selenium - for running Laravel Dusk browser tests.

You can take a look at my setup by looking at the docker-compose.yml file and the additional configuration in the /docker folder.

Below I want to highlight a couple of key things that I learned while building this new setup.

Split up configuration

The docker-compose.yml file tends to grow very big. Split it up by providing a build definition for each server.

Multiple MySql databases

The default MySQL image only provides you an easy way to create a single database. In my case, I wanted to have 2 databases: one for the website and another one for running the acceptance tests.

To achieve this, create a shell script that you want to run when the image is build:

#!/bin/sh

CREATE DATABASE blog;
CREATE DATABASE blog_dusk;
GRANT ALL PRIVILEGES ON *.* TO 'blog'@'%';

Then add a volume to map your local provisioning script onto /docker-entrypoint-initdb.d:

mysql:
  container_name: mysql
  build: ./docker/mysql
  volumes:
    - ./docker/mysql/provisioning:/docker-entrypoint-initdb.d

More details can be found in the MyQSL Docker image documentation.

Docker hostnames in .env

This might be trivial to some, but cost me some headaches. In your environment secrets, do not reference localhost but use the service names you configured.

So, in my case the database hostname is mysql, the Redis hostname is redis and the mail hostname is maildev.

Selenium on ARM

Running the default Selenium Docker images on an M1 machine won’t work. Use the Selenium ARM-specific images instead.

Laravel Dusk environment configuration

First, make sure your DuskTestCase (the base test class) is up-to-date with the stub from the Dusk repository.

In your Dusk environment configuration (.env.dusk.local), set APP_URL='http://nginx' and DUSK_DRIVER_URL='http://selenium:4444/wd/hub.

Maildev instead of Mailhog

Homestead comes with Mailhog to locally test emails. It intercepts emails your Laravel application sends and presents them in a nice web interface.

However, Mailhog has not been updated for about 2 year now and there are a lot of open issues that indicate it is not maintained any longer.

As an alternative, I switched to using Maildev. It works in much the same way and I’m very happy about it.

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