Easy installation of PHP extensions in official PHP Docker images

This repository contains a script that can be used to easily install a PHP extension inside the official PHP Docker images.

The script will install all the required APT/APK packages; at the end of the script execution, the no-more needed packages will be removed so that the image will be much smaller.

Supported docker images are:

• Debian-based docker images: since jessie (Debian 8) (minimum PHP version: 5.5)
• Alpine-based docker images: since Alpine 3.9 (minimum PHP version: 7.1)

See also the notes in the Special requirements section.

Usage

You have many ways to use this script within your Dockerfiles.

Here's a list of sample Dockerfiles that install the GD and xdebug PHP extensions:

Downloading the script on the fly with ADD

FROM php:7.2-cli

ADD https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions /usr/local/bin/

RUN chmod +x /usr/local/bin/install-php-extensions && \
    install-php-extensions gd xdebug

Downloading the script on the fly with curl

FROM php:7.2-cli

RUN curl -sSLf \
        -o /usr/local/bin/install-php-extensions \
        https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions && \
    chmod +x /usr/local/bin/install-php-extensions && \
    install-php-extensions gd xdebug

Direct execution with curl

FROM php:8.2-cli

RUN curl -sSL https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions -o - | sh -s \
      gd xdebug

Copying the script from a Docker image

FROM php:7.2-cli

COPY --from=mlocati/php-extension-installer /usr/bin/install-php-extensions /usr/local/bin/

RUN install-php-extensions gd xdebug

Warning: by using this method you may use an outdated version of the mlocati/php-extension-installer image. You may want to run docker pull mlocati/php-extension-installer in order to use an up-to-date version.

Using the script of a Docker image

RUN  --mount=type=bind,from=mlocati/php-extension-installer:1.5,source=/usr/bin/install-php-extensions,target=/usr/local/bin/install-php-extensions \
      install-php-extensions gd xdebug

Warning: by using this method you may use an outdated version of the mlocati/php-extension-installer image. You may want to run docker pull mlocati/php-extension-installer in order to use an up-to-date version.

Installing specific versions of an extension

Simply append -<version> to the module name. For example:

install-php-extensions xdebug-2.9.7

The script also supports resolving compatible versions by prefixing the version with a caret (^). For example:

# Install the most recent xdebug 2.x version (for example 2.9.8)
install-php-extensions xdebug-^2
# Install the most recent xdebug 2.8.x version (for example 2.8.1)
install-php-extensions xdebug-^2.8

Pre-release versions extensions available on PECL can be setup by suffixing the extension's name with its state i.e. alpha, beta, rc, preview, devel or snapshot. For example:

install-php-extensions xdebug-beta

TIP: When the latest version available on PECL is not stable, and you want to keep the last stable version, force it by suffixing the extension's name with the stable state. For example:

install-php-extensions mongodb-stable

Installing an extension from its source code

You can also install PHP extensions from source code (provided that it comes with a package.xml or a package2.xml file).

Accepted formats are:

• A short version for repositories hosted on GitHub.
  For example, for the php-memcached-dev/php-memcached GitHub repository, you can simply write:

  # Install from a specific commit (full commit SHA-1)
  install-php-extensions php-memcached-dev/php-memcached@8f106564e6bb005ca6100b12ccc89000daafa9d8
  # Install from a specific commit (short commit SHA-1)
  install-php-extensions php-memcached-dev/php-memcached@8f106564e6bb
  # Install from tag v3.2.0RC2
  install-php-extensions php-memcached-dev/[email protected]
  install-php-extensions php-memcached-dev/php-memcached@refs/tags/v3.2.0RC2
  # Install from branch master
  install-php-extensions php-memcached-dev/php-memcached@master
  install-php-extensions php-memcached-dev/php-memcached@refs/heads/master

• An URL providing an archive containing the source code.
  Examples:

  # tgz archive for commit 8f106564e6bb005ca6100b12ccc89000daafa9d8
  install-php-extensions https://codeload.github.com/php-memcached-dev/php-memcached/tar.gz/8f106564e6bb005ca6100b12ccc89000daafa9d8
  # tgz archive for tag v3.1.5
  install-php-extensions https://codeload.github.com/php-memcached-dev/php-memcached/tar.gz/refs/tags/v3.1.5
  # tgz archive for branch master
  install-php-extensions https://codeload.github.com/php-memcached-dev/php-memcached/tar.gz/refs/heads/master

• The absolute path of a local directory.
  Examples:

  # Download the source code
  curl -o /tmp/source.tgz https://codeload.github.com/php-memcached-dev/php-memcached/tar.gz/refs/tags/v3.1.5
  tar xzf /tmp/source.tgz -C /tmp
  install-php-extensions /tmp/php-memcached-3.1.5
  

Installing composer

You can also install composer, and you also can specify a major version of it, or a full version.

Examples:

# Install the latest version
install-php-extensions @composer
# Install the latest 1.x version
install-php-extensions @composer-1
# Install a specific version
install-php-extensions @composer-2.0.2

Issue with Let's Encrypt certificates

The root CA certificate of Let's Encrypt changes (more details here).
That breaks old linux distributions, namely:

• Debian Jessie (8)
• Debian Stretch (9)
• Alpine Linux 3.7
• Alpine Linux 3.8

This script can fix this issue: simply pass @fix_letsencrypt as an argument:

install-php-extensions @fix_letsencrypt

Supported PHP extensions

Number of supported extensions: 138

PS: the pre-installed PHP extensions are excluded from this list. You can list them with the following command (change php:7.2-cli to reflect the PHP version you are interested in):

$ docker run --rm php:7.2-cli php -m
[PHP Modules]
Core
ctype
curl
date
dom
fileinfo
filter
ftp
hash
iconv
json
libxml
mbstring
mysqlnd
openssl
pcre
PDO
pdo_sqlite
Phar
posix
readline
Reflection
session
SimpleXML
sodium
SPL
sqlite3
standard
tokenizer
xml
xmlreader
xmlwriter
zlib

[Zend Modules]

Configuration

You can configure the behavior of the script, as well as fine-tune some extensions in order fit your needs, by using environment variables.

Here's an example:

IPE_LZF_BETTERCOMPRESSION=1 install-php-extensions lzf

Here's the list of all the supported environment variables:

Special requirements

Some extensions have special requirements:

How do I know which Linux distribution I am using?

You can run this command:

cat /etc/os-release

For example:

• for Debian 11 (Bullseye) you'll see:

  PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"

• for Alpine Linux 3.14 you'll see:

  PRETTY_NAME="Alpine Linux v3.14"

Tests

When submitting a pull request, a GitHub Action is executed to check if affected PHP extensions actually work (see below).

Furthermore, we also check that new versions of extensions in the PECL repository will still work. This is done on a scheduled basis with another GitHub Action.
In case of failure, a message is sent to a Telegram Channel.
Feel free to subscribe to it to receive failure notifications.

How to contribute

Formatting code

Before submitting any pull request, you should execute the lint script in the scripts directory (or lint.bat on Windows).

If you don't do that, and if there's a coding style error, you'll see that the Check shell coding style and/or the Check PHP coding style GitHub Actions will fail.

The error will be something like this:

--- filename.orig
+++ filename
@@ -line number,7 +line number,7 @@
     good line of code #1
     good line of code #2
     good line of code #3
-    the original line with a wrong coding style
+    the line wrong coding style that has been corrected
     good line of code #4
     good line of code #5
     good line of code #6

So, you should fix highlighted line (the one(s) at line number) by replacing what you see after the - with what you see after the +

Adding support to a new PHP extension?

1. change the install-php-extensions script
2. update the data/supported-extensions file, adding a new line with the handle of the extension and the list of supported PHP versions
3. if the extension requires ZTS images:
   add a new line to the data/special-requirements file, with the extension handle followed by a space and zts

See this pull request for an example.

Changing the supported PHP versions for an already supported PHP extension?

1. change the install-php-extensions script
2. update the data/supported-extensions file, adding the new PHP version to the existing line corresponding to the updated extension

See this pull request for an example.

Improving code for an already supported extension?

If you change some code that affects one or more extensions, please add a line with Test: extension1, extension2 to the message of one of the pull request commits. That way, the test jobs will check the extension even if you don't touch the data/supported-extensions file.

Here's an example of a commit message:

Improve the GD and ZIP extensions

Test: gd, zip

Tests only check the installation of a single PHP extension at a time. If you want to test installing more PHP extensions at the same time, use a commit message like this:

Improve the GD and ZIP extensions

Test: gd+zip

If your pull request contains multiple commits, we'll check the "Test:" message of every commit. If you want to stop parsing next commits, add -STOP- in the "Test:" line, for example:

Improve the GD and ZIP extensions

Test: gd, zip, -STOP-

See this pull request for an example.

PHP requirements and configure options

PHP extensions published on the PECL archive contain a package.xml (or package2.xml) file describing the supported PHP versions and the options that can be used to compile it. When we add support for a new PHP extension, and when a new version of a PHP extension is released, we have to check those constraints.

It's a rather tedious task, so I developed a project that lets you easily check those constraints: you can find it at https://mlocati.github.io/pecl-info (here you can find its source code).

For the maintainers

See the MAINTAINERS.md file.

Do you want to really say thank you?

You can offer me a monthly coffee or a one-time coffee 😉