Painless PHP (Using docker)

This guide will demonstrate a way of containerisation of php application along with rapid development.

What we will do

1. Inspect source structure.
2. Explaining Dockerfile.
3. Explaining docker-compose.yml.
4. Demonstrating development cycle.

1. Inspect source structure:

.
├── src
│   └── index.php
├── Dockerfile
└── docker-compose.yml

Here the src directory is containing a simple index.php for demonstration purpose. Alongside the src directory i am having a Dockerfile & docker-compose.yml file responsible for containerisation of our project.

2. Explaining Dockerfile:

Dockerfile is responsible for describing our image for docker container. Contents of the docker file is following

FROM php:apache-buster

COPY ./src/* /var/www/html

CMD ["apache2-foreground"]

As a base image i choose php:apache-buster. This image pre-install php and apache server within it. apache server inside of this image serves file from /var/www/html folder

Then i copied the content of src folder into the /var/www/html folder so that all of my developed source code is avaiable inside the image.

Then started the apache server in foreground mode. Actually i copied it from the command of the base image.

So while starting container with image, a container will fireup where apache & php already installed and my source codes are inside the folder where apache serving files from.

3. Explaining docker-compose.yml

docker-compose.yml is responsible for orchastrate the with necessary configuration. Following are the contents of this file

version: '3.2'
services:
  awesome-app:
    build:
      context: .
      dockerfile: Dockerfile
    image: awesome-app:latest
    ports:
    - 80:80
    volumes:
    - type: bind
      source: ./src
      target: /var/www/html

At the very begining of this file I mentioned the compose file version.

Then I declared the services. I named our service awesome-app. Inside the build portion i am specifying the context path Dockerfile to build image from. Then I specify the image name alongside of it's tag. After that I exposed the port 80 into the host, so that I can access the apache from the host.

The last portion is the tricky part. I am binding a volume from hosts ./src directory to /var/www/html inside of the container. The purpose of this volume binding is so that while changing the file inside of my hosts ./src folder all these changes can be seen by the apache running inside the container. As apache can see my changeset inside the src folder so i can change code and see the changed result without restarting or rebulding the image.

4. Demonstrating development cycle.

To demonstrate a development cycle i will do followings

1. Start awesome-app.
2. Check existing output.
3. Change code.
4. Inspect changed output.

1. Start awesome-app

To start my awesome-app we will use docker-compose

docker-compose up -d

This will create a awesome-app container in the background

2. Check existing output

To inspect the output of existing codebase i will use curl

curl -i http://localhost

HTTP/1.1 200 OK
Date: Thu, 25 Aug 2022 19:27:35 GMT
Server: Apache/2.4.38 (Debian)
X-Powered-By: PHP/8.1.9
Content-Length: 12
Content-Type: text/html; charset=UTF-8

Hello world

3. Change code:

Now i will modify code inside index.php

<?php echo "My Awesome app says hello world\n"; ?>

4. Inspect changed output.

curl -i http://localhost

HTTP/1.1 200 OK
Date: Thu, 25 Aug 2022 19:37:24 GMT
Server: Apache/2.4.38 (Debian)
X-Powered-By: PHP/8.1.9
Content-Length: 32
Content-Type: text/html; charset=UTF-8

My Awesome app says hello world

Changes done in the source code is reflected immediately.