How To Containerize a Laravel Application for Development with Docker Compose on Ubuntu 18.04

Introduction

To containerize an application refers to the process of adapting an application and its components in order to be able to run it in lightweight environments known as containers. Such environments are isolated and disposable, and can be leveraged for developing, testing, and deploying applications to production.

In this guide, we’ll use Docker Compose to containerize a Laravel application for development. When you’re finished, you’ll have a demo Laravel application running on three separate service containers:

• An app service running PHP7.4-FPM;
• A db service running MySQL 5.7;
• An nginx service that uses the app service to parse PHP code before serving the Laravel application to the final user.

To allow for a streamlined development process and facilitate application debugging, we’ll keep application files in sync by using shared volumes. We’ll also see how to use docker-compose exec commands to run Composer and Artisan on the app container.

Prerequisites

• Access to an Ubuntu 18.04 local machine or development server as a non-root user with sudo privileges. If you’re using a remote server, it’s advisable to have an active firewall installed. To set these up, please refer to our Initial Server Setup Guide for Ubuntu 18.04.
• Docker installed on your server, following Steps 1 and 2 of How To Install and Use Docker on Ubuntu 18.04.
• Docker Compose installed on your server, following Step 1 of How To Install Docker Compose on Ubuntu 18.04.

Step 1 — Obtaining the Demo Application

To get started, we’ll fetch the demo Laravel application from its Github repository. We’re interested in the tutorial-01 branch, which contains the basic Laravel application we’ve created in the first guide of this series.

To obtain the application code that is compatible with this tutorial, download release tutorial-1.0.1 to your home directory with:

cd ~
curl -L https://github.com/do-community/travellist-laravel-demo/archive/tutorial-1.0.1.zip -o travellist.zip

We’ll need the unzip command to unpack the application code. In case you haven’t installed this package before, do so now with:

sudo apt update
sudo apt install unzip

Now, unzip the contents of the application and rename the unpacked directory for easier access:

unzip travellist.zip
mv travellist-laravel-demo-tutorial-1.0.1 travellist-demo

Navigate to the travellist-demo directory:

cd travellist-demo

In the next step, we’ll create a .env configuration file to set up the application.

Step 2 — Setting Up the Application’s .env File

The Laravel configuration files are located in a directory called config, inside the application’s root directory. Additionally, a .env file is used to set up environment-dependent configuration, such as credentials and any information that might vary between deploys. This file is not included in revision control.

The values contained in the .env file will take precedence over the values set in regular configuration files located at the config directory. Each installation on a new environment requires a tailored environment file to define things such as database connection settings, debug options, application URL, among other items that may vary depending on which environment the application is running.

We’ll now create a new .env file to customize the configuration options for the development environment we’re setting up. Laravel comes with an example.env file that we can copy to create our own:

cp .env.example .env

Open this file using nano or your text editor of choice:

nano .env

The current .env file from the travellist demo application contains settings to use a local MySQL database, with 127.0.0.1 as database host. We need to update the DB_HOST variable so that it points to the database service we will create in our Docker environment. In this guide, we’ll call our database service db. Go ahead and replace the listed value of DB_HOST with the database service name:

APP_NAME=Travellist
APP_ENV=dev
APP_KEY=
APP_DEBUG=true
APP_URL=http://localhost:8000

LOG_CHANNEL=stack

DB_CONNECTION=mysql
DB_HOST=db
DB_PORT=3306
DB_DATABASE=travellist
DB_USERNAME=travellist_user
DB_PASSWORD=password
...

Feel free to also change the database name, username, and password, if you wish. These variables will be leveraged in a later step where we’ll set up the docker-compose.yml file to configure our services.

Save the file when you’re done editing. If you used nano, you can do that by pressing Ctrl+x, then Y and Enter to confirm.

Step 3 — Setting Up the Application’s Dockerfile

Although both our MySQL and Nginx services will be based on default images obtained from the Docker Hub, we still need to build a custom image for the application container. We’ll create a new Dockerfile for that.

Our travellist image will be based on the php:7.4-fpm official PHP image from Docker Hub. On top of that basic PHP-FPM environment, we’ll install a few extra PHP modules and the Composer dependency management tool.

We’ll also create a new system user; this is necessary to execute artisan and composer commands while developing the application. The uid setting ensures that the user inside the container has the same uid as your system user on your host machine, where you’re running Docker. This way, any files created by these commands are replicated in the host with the correct permissions. This also means that you’ll be able to use your code editor of choice in the host machine to develop the application that is running inside containers.

Create a new Dockerfile with:

nano Dockerfile

Copy the following contents to your Dockerfile:

FROM php:7.4-fpm

# Arguments defined in docker-compose.yml
ARG user
ARG uid

# Install system dependencies
RUN apt-get update && apt-get install -y \
    git \
    curl \
    libpng-dev \
    libonig-dev \
    libxml2-dev \
    zip \
    unzip

# Clear cache
RUN apt-get clean && rm -rf /var/lib/apt/lists/*

# Install PHP extensions
RUN docker-php-ext-install pdo_mysql mbstring exif pcntl bcmath gd

# Get latest Composer
COPY --from=composer:latest /usr/bin/composer /usr/bin/composer

# Create system user to run Composer and Artisan Commands
RUN useradd -G www-data,root -u $uid -d /home/$user $user
RUN mkdir -p /home/$user/.composer && \
    chown -R $user:$user /home/$user

# Set working directory
WORKDIR /var/www

USER $user

Don’t forget to save the file when you’re done.

Our Dockerfile starts by defining the base image we’re using: php:7.4-fpm.

After installing system packages and PHP extensions, we install Composer by copying the composer executable from its latest official image to our own application image.

A new system user is then created and set up using the user and uid arguments that were declared at the beginning of the Dockerfile. These values will be injected by Docker Compose at build time.

Finally, we set the default working dir as /var/www and change to the newly created user. This will make sure you’re connecting as a regular user, and that you’re on the right directory, when running composer and artisan commands on the application container.

Step 4 — Setting Up Nginx Configuration and Database Dump Files

When creating development environments with Docker Compose, it is often necessary to share configuration or initialization files with service containers, in order to set up or bootstrap those services. This practice facilitates making changes to configuration files to fine-tune your environment while you’re developing the application.

We’ll now set up a folder with files that will be used to configure and initialize our service containers.

To set up Nginx, we’ll share a travellist.conf file that will configure how the application is served. Create the docker-compose/nginx folder with:

mkdir -p docker-compose/nginx

Open a new file named travellist.conf within that directory:

nano docker-compose/nginx/travellist.conf

Copy the following Nginx configuration to that file:

server {
    listen 80;
    index index.php index.html;
    error_log  /var/log/nginx/error.log;
    access_log /var/log/nginx/access.log;
    root /var/www/public;
    location ~ \.php$ {
        try_files $uri =404;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass app:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
    }
    location / {
        try_files $uri $uri/ /index.php?$query_string;
        gzip_static on;
    }
}

This file will configure Nginx to listen on port 80 and use index.php as default index page. It will set the document root to /var/www/public, and then configure Nginx to use the app service on port 9000 to process *.php files.

Save and close the file when you’re done editing.

To set up the MySQL database, we’ll share a database dump that will be imported when the container is initialized. This is a feature provided by the MySQL 5.7 image we’ll be using on that container.

Create a new folder for your MySQL initialization files inside the docker-compose folder:

mkdir docker-compose/mysql

Open a new .sql file:

nano docker-compose/mysql/init_db.sql

The following MySQL dump is based on the database we’ve set up in our Laravel on LEMP guide. It will create a new table named places. Then, it will populate the table with a set of sample places.

Add the following code to the file:

DROP TABLE IF EXISTS `places`;

CREATE TABLE `places` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `visited` tinyint(1) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

INSERT INTO `places` (name, visited) VALUES ('Berlin',0),('Budapest',0),('Cincinnati',1),('Denver',0),('Helsinki',0),('Lisbon',0),('Moscow',1),('Nairobi',0),('Oslo',1),('Rio',0),('Tokyo',0);

The places table contains three fields: id, name, and visited. The visited field is a flag used to identify the places that are still to go. Feel free to change the sample places or include new ones. Save and close the file when you’re done.

We’ve finished setting up the application’s Dockerfile and the service configuration files. Next, we’ll set up Docker Compose to use these files when creating our services.

Step 5 — Creating a Multi-Container Environment with Docker Compose

Docker Compose enables you to create multi-container environments for applications running on Docker. It uses service definitions to build fully customizable environments with multiple containers that can share networks and data volumes. This allows for a seamless integration between application components.

To set up our service definitions, we’ll create a new file called docker-compose.yml. Typically, this file is located at the root of the application folder, and it defines your containerized environment, including the base images you will use to build your containers, and how your services will interact.

We’ll define three different services in our docker-compose.yml file: app, db, and nginx.

The app service will build an image called travellist, based on the Dockerfile we’ve previously created. The container defined by this service will run a php-fpm server to parse PHP code and send the results back to the nginx service, which will be running on a separate container. The mysql service defines a container running a MySQL 5.7 server. Our services will share a bridge network named travellist.

The application files will be synchronized on both the app and the nginx services via bind mounts. Bind mounts are useful in development environments because they allow for a performant two-way sync between host machine and containers.

Create a new docker-compose.yml file at the root of the application folder:

nano docker-compose.yml

A typical docker-compose.yml file starts with a version definition, followed by a services node, under which all services are defined. Shared networks are usually defined at the bottom of that file.

To get started, copy this boilerplate code into your docker-compose.yml file:

version: "3.7"
services:


networks:
  travellist:
    driver: bridge

We’ll now edit the services node to include the app, db and nginx services.

The app Service

The app service will set up a container named travellist-app. It builds a new Docker image based on a Dockerfile located in the same path as the docker-compose.yml file. The new image will be saved locally under the name travellist.

Even though the document root being served as the application is located in the nginx container, we need the application files somewhere inside the app container as well, so we’re able to execute command line tasks with the Laravel Artisan tool.

Copy the following service definition under your services node, inside the docker-compose.yml file:

  app:
    build:
      args:
        user: sammy
        uid: 1000
      context: ./
      dockerfile: Dockerfile
    image: travellist
    container_name: travellist-app
    restart: unless-stopped
    working_dir: /var/www/
    volumes:
      - ./:/var/www
    networks:
      - travellist

These settings do the following:

• build: This configuration tells Docker Compose to build a local image for the app service, using the specified path (context) and Dockerfile for instructions. The arguments user and uid are injected into the Dockerfile to customize user creation commands at build time.
• image: The name that will be used for the image being built.
• container_name: Sets up the container name for this service.
• restart: Always restart, unless the service is stopped.
• working_dir: Sets the default directory for this service as /var/www.
• volumes: Creates a shared volume that will synchronize contents from the current directory to /var/www inside the container. Notice that this is not your document root, since that will live in the nginx container.
• networks: Sets up this service to use a network named travellist.

The db Service

The db service uses a pre-built MySQL 5.7 image from Docker Hub. Because Docker Compose automatically loads .env variable files located in the same directory as the docker-compose.yml file, we can obtain our database settings from the Laravel .env file we created in a previous step.

Include the following service definition in your services node, right after the app service:

  db:
    image: mysql:5.7
    container_name: travellist-db
    restart: unless-stopped
    environment:
      MYSQL_DATABASE: ${DB_DATABASE}
      MYSQL_ROOT_PASSWORD: ${DB_PASSWORD}
      MYSQL_PASSWORD: ${DB_PASSWORD}
      MYSQL_USER: ${DB_USERNAME}
      SERVICE_TAGS: dev
      SERVICE_NAME: mysql
    volumes:
      - ./docker-compose/mysql:/docker-entrypoint-initdb.d
    networks:
      - travellist

These settings do the following:

• image: Defines the Docker image that should be used for this container. In this case, we’re using a MySQL 5.7 image from Docker Hub.
• container_name: Sets up the container name for this service: travellist-db.
• restart: Always restart this service, unless it is explicitly stopped.
• environment: Defines environment variables in the new container. We’re using values obtained from the Laravel .env file to set up our MySQL service, which will automatically create a new database and user based on the provided environment variables.
• volumes: Creates a volume to share a .sql database dump that will be used to initialize the application database. The MySQL image will automatically import .sql files placed in the /docker-entrypoint-initdb.d directory inside the container.
• networks: Sets up this service to use a network named travellist.

The nginx Service

The nginx service uses a pre-built Nginx image on top of Alpine, a lightweight Linux distribution. It creates a container named travellist-nginx, and it uses the ports definition to create a redirection from port 8000 on the host system to port 80 inside the container.

Include the following service definition in your services node, right after the db service:

  nginx:
    image: nginx:1.17-alpine
    container_name: travellist-nginx
    restart: unless-stopped
    ports:
      - 8000:80
    volumes:
      - ./:/var/www
      - ./docker-compose/nginx:/etc/nginx/conf.d
    networks:
      - travellist

These settings do the following:

• image: Defines the Docker image that should be used for this container. In this case, we’re using the Alpine Nginx 1.17 image.
• container_name: Sets up the container name for this service: travellist-nginx.
• restart: Always restart this service, unless it is explicitly stopped.
• ports: Sets up a port redirection that will allow external access via port 8000 to the web server running on port 80 inside the container.
• volumes: Creates two shared volumes. The first one will synchronize contents from the current directory to /var/www inside the container. This way, when you make local changes to the application files, they will be quickly reflected in the application being served by Nginx inside the container. The second volume will make sure our Nginx configuration file, located at docker-compose/nginx/travellist.conf, is copied to the container’s Nginx configuration folder.
• networks: Sets up this service to use a network named travellist.

Finished docker-compose.yml File

This is how our finished docker-compose.yml file looks like:

version: "3.7"
services:
  app:
    build:
      args:
        user: sammy
        uid: 1000
      context: ./
      dockerfile: Dockerfile
    image: travellist
    container_name: travellist-app
    restart: unless-stopped
    working_dir: /var/www/
    volumes:
      - ./:/var/www
    networks:
      - travellist

  db:
    image: mysql:5.7
    container_name: travellist-db
    restart: unless-stopped
    environment:
      MYSQL_DATABASE: ${DB_DATABASE}
      MYSQL_ROOT_PASSWORD: ${DB_PASSWORD}
      MYSQL_PASSWORD: ${DB_PASSWORD}
      MYSQL_USER: ${DB_USERNAME}
      SERVICE_TAGS: dev
      SERVICE_NAME: mysql
    volumes:
      - ./docker-compose/mysql:/docker-entrypoint-initdb.d
    networks:
      - travellist

  nginx:
    image: nginx:alpine
    container_name: travellist-nginx
    restart: unless-stopped
    ports:
      - 8000:80
    volumes:
      - ./:/var/www
      - ./docker-compose/nginx:/etc/nginx/conf.d/
    networks:
      - travellist

networks:
  travellist:
    driver: bridge

Make sure you save the file when you’re done.

Step 6 — Running the Application with Docker Compose

We’ll now use docker-compose commands to build the application image and run the services we specified in our setup.

Build the app image with the following command:

docker-compose build app

This command might take a few minutes to complete. You’ll see output similar to this:

Output
Building app
Step 1/11 : FROM php:7.4-fpm
 ---> fa37bd6db22a
Step 2/11 : ARG user
 ---> Running in f71eb33b7459
Removing intermediate container f71eb33b7459
 ---> 533c30216f34
Step 3/11 : ARG uid
 ---> Running in 60d2d2a84cda
Removing intermediate container 60d2d2a84cda
 ---> 497fbf904605
Step 4/11 : RUN apt-get update && apt-get install -y     git     curl     libpng-dev     libonig-dev     ...
Step 7/11 : COPY --from=composer:latest /usr/bin/composer /usr/bin/composer
 ---> e499f74896e3
Step 8/11 : RUN useradd -G www-data,root -u $uid -d /home/$user $user
 ---> Running in 232ef9c7dbd1
Removing intermediate container 232ef9c7dbd1
 ---> 870fa3220ffa
Step 9/11 : RUN mkdir -p /home/$user/.composer &&     chown -R $user:$user /home/$user
 ---> Running in 7ca8c0cb7f09
Removing intermediate container 7ca8c0cb7f09
 ---> 3d2ef9519a8e
Step 10/11 : WORKDIR /var/www
 ---> Running in 4a964f91edfa
Removing intermediate container 4a964f91edfa
 ---> 00ada639da21
Step 11/11 : USER $user
 ---> Running in 9f8e874fede9
Removing intermediate container 9f8e874fede9
 ---> fe176ff4702b

Successfully built fe176ff4702b
Successfully tagged travellist:latest

When the build is finished, you can run the environment in background mode with:

docker-compose up -d

Output
Creating travellist-db    ... done
Creating travellist-app   ... done
Creating travellist-nginx ... done

This will run your containers in the background. To show information about the state of your active services, run:

docker-compose ps

You’ll see output like this:

Output
      Name                    Command              State          Ports        
-------------------------------------------------------------------------------
travellist-app     docker-php-entrypoint php-fpm   Up      9000/tcp            
travellist-db      docker-entrypoint.sh mysqld     Up      3306/tcp, 33060/tcp 
travellist-nginx   nginx -g daemon off;            Up      0.0.0.0:8000->80/tcp

Your environment is now up and running, but we still need to execute a couple commands to finish setting up the application. You can use the docker-compose exec command to execute commands in the service containers, such as an ls -l to show detailed information about files in the application directory:

docker-compose exec app ls -l

Output
total 256
-rw-rw-r-- 1 sammy 1001    738 Jan 15 16:46 Dockerfile
-rw-rw-r-- 1 sammy 1001    101 Jan  7 08:05 README.md
drwxrwxr-x 6 sammy 1001   4096 Jan  7 08:05 app
-rwxr-xr-x 1 sammy 1001   1686 Jan  7 08:05 artisan
drwxrwxr-x 3 sammy 1001   4096 Jan  7 08:05 bootstrap
-rw-rw-r-- 1 sammy 1001   1501 Jan  7 08:05 composer.json
-rw-rw-r-- 1 sammy 1001 179071 Jan  7 08:05 composer.lock
drwxrwxr-x 2 sammy 1001   4096 Jan  7 08:05 config
drwxrwxr-x 5 sammy 1001   4096 Jan  7 08:05 database
drwxrwxr-x 4 sammy 1001   4096 Jan 15 16:46 docker-compose
-rw-rw-r-- 1 sammy 1001   1015 Jan 15 16:45 docker-compose.yml
-rw-rw-r-- 1 sammy 1001   1013 Jan  7 08:05 package.json
-rw-rw-r-- 1 sammy 1001   1405 Jan  7 08:05 phpunit.xml
drwxrwxr-x 2 sammy 1001   4096 Jan  7 08:05 public
-rw-rw-r-- 1 sammy 1001    273 Jan  7 08:05 readme.md
drwxrwxr-x 6 sammy 1001   4096 Jan  7 08:05 resources
drwxrwxr-x 2 sammy 1001   4096 Jan  7 08:05 routes
-rw-rw-r-- 1 sammy 1001    563 Jan  7 08:05 server.php
drwxrwxr-x 5 sammy 1001   4096 Jan  7 08:05 storage
drwxrwxr-x 4 sammy 1001   4096 Jan  7 08:05 tests
-rw-rw-r-- 1 sammy 1001    538 Jan  7 08:05 webpack.mix.js

We’ll now run composer install to install the application dependencies:

docker-compose exec app composer install

You’ll see output like this:

Output
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Package operations: 85 installs, 0 updates, 0 removals
  - Installing doctrine/inflector (1.3.1): Downloading (100%)         
  - Installing doctrine/lexer (1.2.0): Downloading (100%)         
  - Installing dragonmantank/cron-expression (v2.3.0): Downloading (100%)         
  - Installing erusev/parsedown (1.7.4): Downloading (100%)         
  - Installing symfony/polyfill-ctype (v1.13.1): Downloading (100%)         
  - Installing phpoption/phpoption (1.7.2): Downloading (100%)         
  - Installing vlucas/phpdotenv (v3.6.0): Downloading (100%)         
  - Installing symfony/css-selector (v5.0.2): Downloading (100%)        
…
Generating optimized autoload files
> Illuminate\Foundation\ComposerScripts::postAutoloadDump
> @php artisan package:discover --ansi
Discovered Package: facade/ignition
Discovered Package: fideloper/proxy
Discovered Package: laravel/tinker
Discovered Package: nesbot/carbon
Discovered Package: nunomaduro/collision
Package manifest generated successfully.

The last thing we need to do before testing the application is to generate a unique application key with the artisan Laravel command-line tool. This key is used to encrypt user sessions and other sensitive data:

docker-compose exec app php artisan key:generate

Output
Application key set successfully.

Now go to your browser and access your server’s domain name or IP address on port 8000:

http://server_domain_or_IP:8000

You’ll see a page like this:

You can use the logs command to check the logs generated by your services:

docker-compose logs nginx

Attaching to travellist-nginx
travellist-nginx | 192.168.160.1 - - [23/Jan/2020:13:57:25 +0000] "GET / HTTP/1.1" 200 626 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
travellist-nginx | 192.168.160.1 - - [23/Jan/2020:13:57:26 +0000] "GET /favicon.ico HTTP/1.1" 200 0 "http://localhost:8000/" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
travellist-nginx | 192.168.160.1 - - [23/Jan/2020:13:57:42 +0000] "GET / HTTP/1.1" 200 626 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
…

If you want to pause your Docker Compose environment while keeping the state of all its services, run:

docker-compose pause

Output
Pausing travellist-db    ... done
Pausing travellist-nginx ... done
Pausing travellist-app   ... done

You can then resume your services with:

docker-compose unpause

Output
Unpausing travellist-app   ... done
Unpausing travellist-nginx ... done
Unpausing travellist-db    ... done

To shut down your Docker Compose environment and remove all of its containers, networks, and volumes, run:

docker-compose down

Output
Stopping travellist-nginx ... done
Stopping travellist-db    ... done
Stopping travellist-app   ... done
Removing travellist-nginx ... done
Removing travellist-db    ... done
Removing travellist-app   ... done
Removing network travellist-laravel-demo_travellist

For an overview of all Docker Compose commands, please check the Docker Compose command-line reference.

Conclusion

In this guide, we’ve set up a Docker environment with three containers using Docker Compose to define our infrastructure in a YAML file.

From this point on, you can work on your Laravel application without needing to install and set up a local web server for development and testing. Moreover, you’ll be working with a disposable environment that can be easily replicated and distributed, which can be helpful while developing your application and also when moving towards a production environment.