$ docker build -t my-php-app .
$ docker run -it --rm --name my-running-app my-php-app

How to install more PHP extensions

Many extensions are already compiled into the image, so it’s worth checking the output of php -m or php -i before going through the effort of compiling more.

We provide the helper scripts docker-php-ext-configure, docker-php-ext-install, and docker-php-ext-enable to more easily install PHP extensions.

In order to keep the images smaller, PHP’s source is kept in a compressed tar file. To facilitate linking of PHP’s source with any extension, we also provide the helper script docker-php-source to easily extract the tar or delete the extracted source. Note: if you do use docker-php-source to extract the source, be sure to delete it in the same layer of the docker image.

FROM php:7.2-cli
RUN docker-php-source extract \
	# do important things \
	&& docker-php-source delete

PHP Core Extensions

For example, if you want to have a PHP-FPM image with iconv and gd extensions, you can inherit the base image that you like, and write your own Dockerfile like this:

FROM php:7.2-fpm
RUN apt-get update && apt-get install -y \
		libfreetype6-dev \
		libjpeg62-turbo-dev \
		libpng-dev \
	&& docker-php-ext-install -j$(nproc) iconv \
	&& docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
	&& docker-php-ext-install -j$(nproc) gd

Remember, you must install dependencies for your extensions manually. If an extension needs custom configure arguments, you can use the docker-php-ext-configure script like this example. There is no need to run docker-php-source manually in this case, since that is handled by the configure and install scripts.

See “Dockerizing Compiled Software” for a description of the technique Tianon uses for determining the necessary build-time dependencies for any bit of software (which applies directly to compiling PHP extensions).