nextcloud-docs/php/content.md

What is PHP?

PHP is a server-side scripting language designed for web development, but which can also be used as a general-purpose programming language. PHP can be added to straight HTML or it can be used with a variety of templating engines and web frameworks. PHP code is usually processed by an interpreter, which is either implemented as a native module on the web-server or as a common gateway interface (CGI).

wikipedia.org/wiki/PHP

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How to use this image.

With Command Line

For PHP projects run through the command line interface (CLI), you can do the following.

Create a Dockerfile in your PHP project

FROM %%IMAGE%%:7.2-cli
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
CMD [ "php", "./your-script.php" ]

Then, run the commands to build and run the Docker image:

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

Run a single PHP script

For many simple, single file projects, you may find it inconvenient to write a complete Dockerfile. In such cases, you can run a PHP script by using the PHP Docker image directly:

$ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/myapp -w /usr/src/myapp %%IMAGE%%:7.2-cli php your-script.php

Note that all variants of the php image contain the PHP cli.

With Apache

More commonly, you will probably want to run PHP in conjunction with Apache httpd. Conveniently, there's a version of the PHP container that's packaged with the Apache web server.

Create a Dockerfile in your PHP project

FROM %%IMAGE%%:7.2-apache
COPY src/ /var/www/html/

Where src/ is the directory containing all your PHP code. Then, run the commands to build and run the Docker image:

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

We recommend that you add a custom php.ini configuration. COPY it into /usr/local/etc/php by adding one more line to the Dockerfile above and running the same commands to build and run:

FROM %%IMAGE%%:7.2-apache
COPY config/php.ini /usr/local/etc/php/
COPY src/ /var/www/html/

Where src/ is the directory containing all your PHP code and config/ contains your php.ini file.

Without a Dockerfile

If you don't want to include a Dockerfile in your project, it is sufficient to do the following:

$ docker run -d -p 80:80 --name my-apache-php-app -v "$PWD":/var/www/html %%IMAGE%%:7.2-apache

Changing DocumentRoot

Some applications may wish to change the default DocumentRoot in Apache (away from /var/www/html). The following demonstrates one way to do so using an environment variable (which can then be modified at container runtime as well):

FROM %%IMAGE%%:7.1-apache

ENV APACHE_DOCUMENT_ROOT /path/to/new/root

RUN sed -ri -e 's!/var/www/html!${APACHE_DOCUMENT_ROOT}!g' /etc/apache2/sites-available/*.conf
RUN sed -ri -e 's!/var/www/!${APACHE_DOCUMENT_ROOT}!g' /etc/apache2/apache2.conf /etc/apache2/conf-available/*.conf

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 %%IMAGE%%:7.2-apache
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 %%IMAGE%%: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).

PECL extensions

Some extensions are not provided with the PHP source, but are instead available through PECL. To install a PECL extension, use pecl install to download and compile it, then use docker-php-ext-enable to enable it:

FROM %%IMAGE%%:7.2-fpm
RUN pecl install redis-4.0.1 \
	&& pecl install xdebug-2.6.0 \
	&& docker-php-ext-enable redis xdebug

FROM %%IMAGE%%:5.6-fpm
RUN apt-get update && apt-get install -y libmemcached-dev zlib1g-dev \
	&& pecl install memcached-2.2.0 \
	&& docker-php-ext-enable memcached

It is strongly recommended that users use an explicit version number in their pecl install invocations to ensure proper PHP version compatibility (PECL does not check the PHP version compatiblity when choosing a version of the extension to install, but does when trying to install it).

For example, memcached-2.2.0 has no PHP version constraints (https://pecl.php.net/package/memcached/2.2.0), but memcached-3.0.4 requires PHP 7.0.0 or newer (https://pecl.php.net/package/memcached/3.0.4). When doing pecl install memcached (no specific version) on PHP 5.6, PECL will try to install the latest release and fail.

Beyond the compatibility issue, it's also a good practice to ensure you know when your dependencies receive updates and can control those updates directly.

Unlike PHP core extensions, PECL extensions should be installed in series to fail properly if something went wrong. Otherwise errors are just skipped by PECL.

For example, pecl install memcached-2.2.0 && pecl install redis-2.2.8 instead of pecl install memcached-2.2.0 redis-2.2.8. However, docker-php-ext-enable memcached redis is fine to be all in one command.

Other extensions

Some extensions are not provided via either Core or PECL; these can be installed too, although the process is less automated:

FROM %%IMAGE%%:5.6-apache
RUN curl -fsSL 'https://xcache.lighttpd.net/pub/Releases/3.2.0/xcache-3.2.0.tar.gz' -o xcache.tar.gz \
	&& mkdir -p xcache \
	&& tar -xf xcache.tar.gz -C xcache --strip-components=1 \
	&& rm xcache.tar.gz \
	&& ( \
		cd xcache \
		&& phpize \
		&& ./configure --enable-xcache \
		&& make -j$(nproc) \
		&& make install \
	) \
	&& rm -r xcache \
	&& docker-php-ext-enable xcache

The docker-php-ext-* scripts can accept an arbitrary path, but it must be absolute (to disambiguate from built-in extension names), so the above example could also be written as the following:

FROM %%IMAGE%%:5.6-apache
RUN curl -fsSL 'https://xcache.lighttpd.net/pub/Releases/3.2.0/xcache-3.2.0.tar.gz' -o xcache.tar.gz \
	&& mkdir -p /tmp/xcache \
	&& tar -xf xcache.tar.gz -C /tmp/xcache --strip-components=1 \
	&& rm xcache.tar.gz \
	&& docker-php-ext-configure /tmp/xcache --enable-xcache \
	&& docker-php-ext-install /tmp/xcache \
	&& rm -r /tmp/xcache

Running as an arbitrary user

For running the FPM variants as an arbitrary user, the --user flag to docker run should be used (which can accept both a username/group in the container's /etc/passwd file like --user daemon or a specific UID/GID like --user 1000:1000).

For running the Apache variants as an arbitrary user, there are several choices:

• If your kernel is version 4.11 or newer, you can add --sysctl net.ipv4.ip_unprivileged_port_start=0 and then --user should work as it does for FPM.
• If you adjust the Apache configuration to use an "unprivileged" port (greater than 1024 by default), then --user should work as it does for FPM regardless of kernel version.
• Otherwise, setting APACHE_RUN_USER and/or APACHE_RUN_GROUP should have the desired effect (for example, -e APACHE_RUN_USER=daemon or -e APACHE_RUN_USER=#1000 -- see the Apache User directive documentation for details on the expected syntax).

"E: Package 'php-XXX' has no installation candidate"

As of docker-library/php#542, this image blocks the installation of Debian's PHP packages. There is some additional discussion of this change in docker-library/php#551 (comment), but the gist is that installing Debian's PHP packages in this image leads to two conflicting installations of PHP in a single image, which is almost certainly not the intended outcome.

For those broken by this change and looking for a workaround to apply in the meantime while a proper fix is developed, adding the following simple line to your Dockerfile should remove the block (with the strong caveat that this will allow the installation of a second installation of PHP, which is definitely not what you're looking for unless you really know what you're doing):

RUN rm /etc/apt/preferences.d/no-debian-php

The proper solution to this error is to either use FROM debian:XXX and install Debian's PHP packages directly, or to use docker-php-ext-install, pecl, and/or phpize to install the necessary additional extensions and utilities.