Installing intl with Wordpress on App Service Linux

This post will cover how to install the “intl” extension on Azure’s Wordpress on Linux

Overview

intl is an installable extension for unicode and globalization support. This is not one of the pre-installed extensions that is a part of the container image that Wordpress on Linux uses. However, this can easily be installed.

Note, that the Wordpress on Linux container image uses Alpine Linux as it’s distro - commands to install this will be using apk.

Installation

1. First, familiarize yourself with How to run Bash scripts in WordPress on Azure App Service (techcommunity) / How to run Bash scripts in WordPress on Linux App Services (GitHub) regarding the startup script location under /home/dev/startup.sh. Next, read Adding PHP extensions for WordPress Linux App Services
   • You will need to do a combination of the first two to get his properly working
2. Add the following into /home/dev/startup.sh:

#!/bin/bash

apk add icu-dev && \
   docker-php-ext-configure intl && \
   docker-php-ext-install intl && \
   docker-php-ext-enable intl

echo "Restarting php-fpm via supervisord.."
supervisorctl restart php-fpm

NOTE: You must add this to /home/dev/startup.sh. Supervisord, which is used to run the startup script execution, will only run startup scripts from this location based on it’s configuration for this image.

• After installation, while in SSH, you can run pear config-show to find the “PHP extension directory” which should have the intl.so shared object file. The directory location is typically something like /usr/local/lib/php/extensions/no-debug-non-zts-20220829.

1. Create a directory named ini under /home/site. In this new directory, create an extensions.ini file with the following:

extension=/path/to/php/ext/dir/intl.so

1. Add an App Setting with the key/value pair of PHP_INI_SCAN_DIR and /usr/local/etc/php/conf.d:/home/site/ini
2. You can now validate that intl has been loaded by adding a phpinfo.php file to /home/site/wwwroot

Make sure to delete phpinfo.php afterwards

Alternative installation

Another method for installation is persist intl.so somewhere under /home. However, you will still need to use a startup script to install icu-dev as that is a needed dependency.

1. Go into SSH (WebSSH), and run the commands earlier that installed intl. This will create a intl.so under the PHP Extension Directory location - use pear config-show to confirm the path.
2. Create a folder named /home/site/ext - navigate to the extension directory and copy the .so - eg., cp intl.so /home/site/ext (or you can do this elsewhere with an absolute path)
3. Follow the rest of the steps above with creating a .ini file under /home/site/ini and adding the PHP_INI_SCAN_DIR App Setting. Add the value of extension=/home/site/ext/intl.so to the .ini file you created under /home/site/ini.
4. Lastly, change your startup script under /home/dev/startup.sh to the following:

#!/bin/bash

apk add icu-dev

echo "Restarting php-fpm via supervisord.."
supervisorctl restart php-fpm

Troubleshooting

If you notice that intl is not being loaded - or - intl.so is not appearing under the PHP extension directory.

Ensure that:

1. App Service Logs are enabled. These can be reviewed if there is any stderr appearing that may be fatal/error related. Or, if the container is now crashing/exiting.
2. If nothing relevant is seen above - go into SSH (assuming that the container is running) and check the output of /tmp/post-startup-script-stderr---supervisor-00000000.log or post-startup-script-stdout---supervisor-00000000.log.

Below is an example of reviewing stdout from a custom startup script in one of these log files:

7fd6d23d988d:/tmp# cat post-startup-script-stdout---supervisor-yb_gtkno.log 
This is being executed from /home/dev/startup.sh..

Furthermore, by reviewing default_docker.log (the equivalent is also shown in /var/log/supervisor/supervisord.log), you can confirm if a startup script is successfully executed by finding the below in logging:

2023-11-13 14:32:40,214 INFO spawned: 'post-startup-script' with pid 237
2023-11-13 14:32:40,306 WARN exited: post-startup-script (exit status 0; not expected)

Although supervisord is showing “not expected” - an exit of status 0 is successful - and what we want to see. An exit code greater than > 0 is deemed unsuccessful.