.. _php:

PHP and PHP-FPM
***************

This tutorial describes how to configure and use PHP and PHP-FPM  on |CL-ATTR|. Although we specifically address PHP this tutorial can serve as a general guide for working with applications in the |CL| :ref:`stateless` environment.

.. contents::
    :local:
    :depth: 1

Overview
********

`PHP (PHP:Hypertext Preprocessor)`_ is an Open Source general-purpose scripting language that is popular with web-developers who leverage its ability to create dynamically generated web pages.  `PHP-FPM (FastCGI Process Manager)`_ is a PHP FastCGI implementation that controls process management, workers, and logging for PHP. The two applications work in conjunction but each has its own configuration.



Prerequisites
*************

* :ref:`Install <bare-metal-install-desktop>` |CL| on your host system
* Use :command:`swupd` to install the :file:`php-basic` bundle.

  .. code-block:: bash

     sudo swupd bundle-add php-basic

.. note::

   PHP does not require a web server for operation.  Refer to :ref:`web-server-install` for instructions on setting up a :abbr:`LAMP (Linux, Apache\*, MySQL, PHP)` server, or use :command:`swupd` to install :file:`nginx` or similar if you need a web server.


Configure PHP
*************

.. important::

   This section does not cover configuring the PHP-FPM service. There is a difference between the two configurations. This section is only looking at the PHP configuration directives, not those of PHP-FPM.


By default PHP looks for configuration settings in the :file:`php.ini` file, which resides in the :file:`usr/share/defaults/php/` path. Because |CL| is designed to be a :ref:`stateless` operating system, you must create an optional configuration file to override the default values. Every time :command:`swupd` updates the system it will overwrite changes to the :file:`/usr/share/defaults` file structure. To save your configuration options through updates, you must create a PHP configuration file in a location that will not be overwritten. The recommended location is within the :file:`/etc` file structure.  For PHP we will create a :file:`/etc/php.d` directory for all PHP config files.

Create a :file:`php.ini`.

.. code-block:: bash

   sudo mkdir -p /etc/php.d
   sudo touch /etc/php.d/my-php.ini

This file can be edited with any of your specific configuration requirements, and will not be overwritten when :command:`swupd` performs an update. The `PHP configuration file`_ documentation has complete detail about what you can set in this file.

Verify the location of the PHP configuration files with the :command:`php --ini` command:

.. code-block:: bash

   php --ini

You should see output like this

.. code-block:: console

   Configuration File (php.ini) Path: /usr/share/defaults/php/
   Loaded Configuration File:         /usr/share/defaults/php/php.ini
   Scan for additional .ini files in: /etc/php.d
   Additional .ini files parsed:


This output indicates that PHP will read the php.ini file from :file:`/usr/share/defaults/php` and will then load any further configuration from :file:`.ini` files in :file:`/etc/php.d/`. We use the :file:`my-php.ini` file in :file:`/etc/php.d` for our specific needs, and allow the defaults to be read from :file:`/usr/share/defaults/php/`. Note that the :file:`my-php.ini` file has not been parsed yet -- this is because the file has no content at this point, and is disregarded.


Install PHP extensions
**********************

PHP extensions are compiled libraries designed to enable specific functions in your PHP code. |CL| provides PHP extensions in the :file:`php-extras` bundle.  Install the bundle with swupd:

.. code-block:: bash

   sudo swupd bundle-add php-extras

Find the list of extensions included in the `php-extras`_ bundle on the |CL| `Store`_.


Enable PHP extensions
*********************

To enable an installed extension we need to add it to the :file:`php.ini` for the composer to use it.

Create the :file:`my-php.ini` file, with the directive to load the php-imagick extension

.. code-block:: bash

   sudo echo "extension=imagick.so" >> /etc/php.d/my-php.ini


No further detail is required to load the extension, but you must restart the php-fpm service for PHP to pick up the modification to the :file:`/etc/php.d/my-php.ini` file.

.. code-block:: bash

   sudo systemctl restart php-fpm

Verify that the imagick extension has been loaded by searching through the runtime list of loaded PHP Modules.

.. code-block:: bash

   php -m | grep imagick


.. note::

   To enable an extension, you must install it, add it to the :file:`my-php.ini` file, and restart the :file:`php-fpm` service. However, some extensions may have configuration options, which will be documented by the extension maintainer. Add the options you need to the :file:`/etc/php.d/my-php.ini` file as described in the extension's documentation. Be sure to restart :file:`php-fpm` after changing the file.

Configure PHP-FPM
*****************

The PHP-FPM configuration file is separate from the :file:`php.ini` file used by PHP. |CL| installs the default :file:`php-fpm.conf` file in :file:`/usr/share/defaults/php` and this file will be overwritten with its default values during each software update. However, PHP-FPM requires that the configuration file exist in that location, and by design will not read configuration options from a different path.

One solution to changing PHP-FPM configuration options in |CL| is to manually override the php-fpm.service unit in systemd to pass an explicit location to a custom :file:`php-fpm.conf` file.

#. Copy the :file:`/usr/share/defaults/php/php-fpm.conf` file to the :file:`/etc/php.d`

   .. code-block:: bash

      sudo cp /usr/share/defaults/php/php-fpm.conf /etc/php.d/php-fpm.conf

#. Make changes to the :file:`php-fpm.conf` file as needed. The `FPM documentation`_ has detail on the configuration options available to PHP-FPM.


#. Edit the systemd service unit file

   .. code-block:: bash

      sudo systemctl edit --full php-fpm.service

   This will open the php-fpm.service file for systemd in your editor.  Change the  :command:`ExecStart` configuration to add the :command:`--fpm-config` option to point to the custom location.

   .. code-block:: bash

      sudo systemctl edit --full php-fpm.service

   .. code-block:: console

      [Unit]
      Description=The PHP FastCGI Process Manager
      After=syslog.target network.target

      [Service]
      Type=notify
      PIDFile=/run/php-fpm.pid
      ExecStart=/usr/sbin/php-fpm --nodaemonize --fpm-config /etc/php.d/php-fpm.conf
      ExecReload=/bin/kill -USR2 $MAINPID
      PrivateTmp=true

      [Install]
      WantedBy=multi-user.target

#. Restart the service

   .. code-block:: bash

      sudo systemctl restart php-fpm.service

#. Verify that the new path has been picked up

   .. code-block:: bash

      sudo systemctl status php-fpm.service

   You should see the new path in the output

   .. code-block:: console

      ● php-fpm.service - The PHP FastCGI Process Manager
      Loaded: loaded (/etc/systemd/system/php-fpm.service; enabled; vendor preset: disabled)
      Active: active (running) since Thu 2019-10-17 13:19:34 PDT; 8min ago
      Main PID: 14452 (php-fpm)
      Status: "Processes active: 0, idle: 0, Requests: 0, slow: 0, Traffic: 0req/sec"
       Tasks: 1
      Memory: 11.1M
      CGroup: /system.slice/php-fpm.service
              └─14452 php-fpm: master process (/etc/php.d/php-fpm.conf)






.. _PHP (PHP:Hypertext Preprocessor): https://www.php.net/

.. _PHP-FPM (FastCGI Process Manager): https://php-fpm.org/

.. _php-extras: https://clearlinux.org/software/bundle/php-extras

.. _Store: https://clearlinux.org/software/

.. _PHP configuration file: https://www.php.net/manual/en/configuration.file.php

.. _FPM documentation: https://www.php.net/manual/en/install.fpm.configuration.php