content.md 9.4 KB
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).
%%LOGO%%
How to use this image
Create a Dockerfile in your PHP project
FROM %%IMAGE%%:8.2-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 "$PWD":/usr/src/myapp -w /usr/src/myapp %%IMAGE%%:8.2-cli php your-script.php
How to install more PHP extensions
Many extensions are already compiled into the image, so it's worth checking the output of php -m or php -i before going through the effort of compiling more.
We provide the helper scripts docker-php-ext-configure, docker-php-ext-install, and docker-php-ext-enable to more easily install PHP extensions.
In order to keep the images smaller, PHP's source is kept in a compressed tar file. To facilitate linking of PHP's source with any extension, we also provide the helper script docker-php-source to easily extract the tar or delete the extracted source. Note: if you do use docker-php-source to extract the source, be sure to delete it in the same layer of the docker image.
FROM %%IMAGE%%:8.2-cli
RUN docker-php-source extract \
# do important things \
&& docker-php-source delete
PHP Core Extensions
For example, if you want to have a PHP-FPM image with the gd extension, you can inherit the base image that you like, and write your own Dockerfile like this:
FROM %%IMAGE%%:8.2-fpm
RUN apt-get update && apt-get install -y \
libfreetype-dev \
libjpeg62-turbo-dev \
libpng-dev \
&& docker-php-ext-configure gd --with-freetype --with-jpeg \
&& docker-php-ext-install -j$(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.
If you are having difficulty figuring out which Debian or Alpine packages need to be installed before docker-php-ext-install, then have a look at the install-php-extensions project. This script builds upon the docker-php-ext-* scripts and simplifies the installation of PHP extensions by automatically adding and removing Debian (apt) and Alpine (apk) packages. For example, to install the GD extension you simply have to run install-php-extensions gd. This tool is contributed by community members and is not included in the images, please refer to their Git repository for installation, usage, and issues.
See also "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).
Default extensions
Some extensions are compiled by default. This depends on the PHP version you are using. Run php -m in the container to get a list for your specific version.
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%%:8.2-cli
RUN pecl install redis-5.3.7 \
&& pecl install xdebug-3.2.1 \
&& docker-php-ext-enable redis xdebug
FROM %%IMAGE%%:8.2-cli
RUN apt-get update && apt-get install -y libmemcached-dev libssl-dev zlib1g-dev \
&& pecl install memcached-3.2.0 \
&& 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 compatibility when choosing a version of the extension to install, but does when trying to install it). 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-3.2.0 && pecl install redis-5.3.7 instead of pecl install memcached-3.2.0 redis-5.3.7. 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%%:8.2-cli
RUN curl -fsSL '[url-to-custom-php-module]' -o module-name.tar.gz \
&& mkdir -p module-name \
&& sha256sum -c "[shasum-value] module-name.tar.gz" \
&& tar -xf module-name.tar.gz -C module-name --strip-components=1 \
&& rm module-name.tar.gz \
&& ( \
cd module-name \
&& phpize \
&& ./configure --enable-module-name \
&& make -j "$(nproc)" \
&& make install \
) \
&& rm -r module-name \
&& docker-php-ext-enable module-name
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%%:8.2-cli
RUN curl -fsSL '[url-to-custom-php-module]' -o module-name.tar.gz \
&& mkdir -p /tmp/module-name \
&& sha256sum -c "[shasum-value] module-name.tar.gz" \
&& tar -xf module-name.tar.gz -C /tmp/module-name --strip-components=1 \
&& rm module-name.tar.gz \
&& docker-php-ext-configure /tmp/module-name --enable-module-name \
&& docker-php-ext-install /tmp/module-name \
&& rm -r /tmp/module-name
Running as an arbitrary user
For running the Apache variants as an arbitrary user, there are a couple choices:
- If your kernel is version 4.11 or newer, you can add
--sysctl net.ipv4.ip_unprivileged_port_start=0(which will be the default in a future version of Docker) and then--usershould work as it does for FPM. - If you adjust the Apache configuration to use an "unprivileged" port (greater than 1024 by default), then
--usershould work as it does for FPM regardless of kernel version.
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).
"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.
Configuration
This image ships with the default php.ini-development and php.ini-production configuration files.
It is strongly recommended to use the production config for images used in production environments!
The default config can be customized by copying configuration files into the $PHP_INI_DIR/conf.d/ directory.
Example
FROM %%IMAGE%%:8.2-fpm-alpine
# Use the default production configuration
RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
In many production environments, it is also recommended to (build and) enable the PHP core OPcache extension for performance. See the upstream OPcache documentation for more details.