How to Install PHP Composer Inside a Docker Container

PHP Composer is a dependency manager for PHP allowing developers to manage project dependencies, libraries, and packages efficiently. Installing Composer inside a Docker container provides a consistent environment across different systems, ensuring that the application behaves the same way on every machine. In this article, we explain the installation process of PHP Composer inside a Docker Container from setting up the Dockerfile to running Composer commands within the container.

What is Docker?

Docker enables developers to create, deploy, and run applications in containers. The Containers are lightweight, portable, and self-sufficient environments that encapsulate everything needed to run an application including code, runtime, libraries, and system tools.

Key Features

• Containerization: Encapsulates an application and its dependencies into a single container that can run consistently across different environments.
• Portability: Containers can run on any system that supports Docker including on-premises servers, cloud environments, and developer laptops.
• Isolation: Provides isolated environments for applications which enhances security and ensures that dependencies do not conflict.
• Efficiency: Containers are lightweight and share the host system's kernel making them more efficient than traditional virtual machines.

What is Composer?

The Composer is a dependency management tool for PHP and It is similar to npm for node.js It allows us to declare the libraries our project depends on and manage them for us.

Key Features

• Dependency Management: Automatically handles the dependencies of your project and you can specify libraries of your project depends on and Composer will manage them for you.
• Autoloading: This provides an easy way to auto-load classes in your project without manually including them.
• Versioning: Ensure that you are using the correct versions of libraries preventing conflicts and breaking changes.
• Repository Management: Supports private and public repositories for packages allowing you to specify where to get dependencies from.

Steps to Install Composer

Step 1: Download Composer

Download composer-setup.exe from the official website.

Step 2 : Install Composer

Once Download is completed. Now It's time to install It. For this open the composer-setup.exe

Now click on Next button then you redirect to another screen look like below. In that screen select add path option and click on next.

Now It will ask user for conformation to install the composer inside the system and Click on install button.

Once click on Install button The System will start the installation process.

Step 3 : Verify Installation

Once Composer is installed. Now It's time to verify the installation by using below command.

composer --version

Primary Terminologies

Here we list out Primary Terminologies for understanding the what is Docker and PHP Composer.

• PHP Composer: A Tool for dependency management in PHP allowing you to declare the libraries our project depends on and managing them for you.
• Docker: A Platform that enables developers to create, deploy and run applications in containers. Containers are lightweight, portable and can run on any System that has Docker installed.
• Dockerfile: A text document that contains all the commands to assemble an image. Using a Dockerfile we can create a customized Docker image.
• Container: A lightweight, Standalone, executable package that includes everything needed to run a piece of software including the code, Runtime, System tools, Libraries and settings.

System Requirements

• Operating System: Any OS that supports Docker like Windows, Linux and macOS
• Docker: Docker Engine installed and running.
• PHP installed inside the Docker container recommended PHP 7.3 or later.
• Composer installed inside the Docker container
• 4GB of RAM and a multi-core CPU are recommended

Install PHP Composer Inside A Docker Container

Here we explain a step by step process to install PHP composer inside a Docker container with related examples and outputs for your reference. Here we created a project and we created a Dockerfile in It and create a public folder in it and in public folder create a index.php file. And write the Dockerfile configuration in that for installing PHP Composer using Docker for your reference.

Step 1 : Setting Up the Dockerfile

First Create a new directory for your project and navigate into it. In that folder create a Dockerfile inside the directory. For follow below commands.

mkdir my-php-project
cd my-php-project

Now create a Dockerfile In that folder.

Step 2 : Create Dockerfile

Now open the Dockerfile in a text editor and add the following content. Below we provide Dockerfile source code for your reference.

# Use the official PHP image as the base image
FROM php:7.4-cli

# Set working directory
WORKDIR /app

# Install Composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer

# Copy the existing application directory contents to the working directory
COPY . /app

# Install application dependencies
RUN composer install

# Command to run your application or PHP script
CMD ["php", "your-script.php"]

Step 3 : Create PHP File

Now create a index.php file in the public folder of the project and write below source code to verify the running of the docker container.

<?php
    echo "Hello, Welcome to GeeksForGeeks!";
?>

Hello, Welcome to GeeksForGeeks!

Step 3 : Building the Docker Image

In the terminal navigate to the directory containing the Dockerfile and build the Docker image using the following command.

docker build -t my-spring-boot-php-app .

Step 4 : Running the Docker Container

Now Run the Docker container using the following command.

docker run -p 8080:8080 --name my-running-app my-spring-boot-php-app

Step 5 : Verify Docker Container

Now Check the if the Docker container is running or not. If yes then we need to check the composer version also from the Docker by using below docker commands.

docker exec -it my-running-app bash
composer --version

Step 6 : Running the Docker Container

Once Docker container is running successfully Then we need verify the output. We already run the container with 8080 port mapping. Now visit below URL for verifying the output.

http://localhost:808

Conclusion

Integrating a Spring Boot application built with Gradle and a PHP application managed by Composer within a Docker container provides a robust and isolated development environment. This approach leverages the power of Docker's multi-stage builds to streamline the process of creating and deploying applications that rely on multiple technologies.

Can I run Composer commands interactively in the container?

Yes, you can run commands interactively by accessing the container shell using

docker exec -it my-running-app bash