Installing Composer in the official PHP Docker image

Composer is a dependency management tool for PHP that has been around for almost 8 years now, but it’s still not included in the official Docker images.

Composer recommends to automate the install using their script. It needs to be downloaded, but the php:7.4-apache image does not contain wget.

FROM php:7.4-apache

RUN apt update && apt-get install -y wget
RUN wget https://raw.githubusercontent.com/composer/getcomposer.org/76a7060ccb93902cd7576b67264ad91c8a2700e2/web/installer -O - -q | php -- --quiet --version=1.10.15
RUN mv composer.phar /usr/local/bin/composer

# Add your project code to Docker image here
# ENV APP_BASE_DIR=/var/www/app \
#     APACHE_DOCUMENT_ROOT=/var/www/app/web
# ADD . $APP_BASE_DIR
# And change directory to your code
# cd $APP_BASE_DIR

RUN composer install

We also want to use composer globally that’s why we added mv composer.phar /usr/local/bin/composer. Now we can execute composer command from anywhere.

The dependencies are now installed successfully, but we still get the following warning:

As there is no 'unzip' command installed zip files are being unpacked using the PHP zip extension.
This may cause invalid reports of corrupted archives. Besides, any UNIX permissions (e.g. executable) defined in the archives will be lost.
Installing 'unzip' may remediate them.

To fix the possibly corrupted archives and UNIX permissions, we need to install the unzip tool. We can also optimize the image to use only one layer to install Composer, and one layer to install dependencies.

FROM php:7.4-apache

# Install Composer
RUN apt update && apt-get install -y wget unzip && \
    wget https://raw.githubusercontent.com/composer/getcomposer.org/76a7060ccb93902cd7576b67264ad91c8a2700e2/web/installer -O - -q | php -- --quiet --version=1.10.15 && \
    mv composer.phar /usr/local/bin/composer

# Add your project code to Docker image here
# ENV APP_BASE_DIR=/var/www/app \
#     APACHE_DOCUMENT_ROOT=/var/www/app/web
# ADD . $APP_BASE_DIR

RUN cd $APP_BASE_DIR && composer install

Finally, we have our Dockerfile ready to integrate the build of our app into a CI/CD pipeline.