Composer in a Docker Image

This will be a short post and this one is mostly for me so I can easily find this information in the future when I need it again. 🙂

Recently I was containerizing some PHP websites that use Composer. If you are not familiar with Composer but you are working with PHP, you will run across it at some point. Composer is a dependency package manager for PHP. Composer manages (install/update) any required libraries and dependencies needed for your PHP site.

To use Composer you must first declare the libraries and dependencies in a composer.json file in your site directory and then you would run Composer and it will do its magic. For more information on Composer visit: https://getcomposer.org/doc/00-intro.md

Back to my task, I needed to install Composer in the containers I was building and run it to install all the dependencies. I needed these actions in the Dockerfile so it would all happen during the container build. After some research on Composer I was able to pull something together. Here is the syntax that I ended up putting in the Dockerfile:

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

# Set working directory for composer (Contains the composer.json file)
WORKDIR /var/www/html/sitename

# Run Composer
RUN composer install

Note: I placed the above code at the end of the Dockerfile ensuring Apache, PHP etc was all in place first.

Thanks for reading and happy Containerizing!

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