Setting PHP versions in Deployer deployments

Sometimes your terminal environment (where you SSH into) uses a different PHP version then that you need. Most hosting companies do have several PHP versions available. But how do you use them, and more importantly, how do you set the right one when deploying new versions with Deployer?

The errors you can run into

In this case, composer required a higher PHP version for some packages. You’re presented with errors like:

Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.
    Problem 1
      - Installation request for ramsey/collection 1.2.2 -> satisfiable by ramsey/collection[1.2.2].
      - ramsey/collection 1.2.2 requires php ^7.3 || ^8 -> your PHP version (7.2.33) does not satisfy that requirement.
    Problem 2
      - ramsey/collection 1.2.2 requires php ^7.3 || ^8 -> your PHP version (7.2.33) does not satisfy that requirement.
      - ramsey/uuid 4.2.3 requires ramsey/collection ^1.0 -> satisfiable by ramsey/collection[1.2.2].
      - Installation request for ramsey/uuid 4.2.3 -> satisfiable by ramsey/uuid[4.2.3].

Which version do you currently run?

Use php -v to get the current version.

Where’s your current version located?

Use which php to retrieve the path

Where’s composer located?

Use which composer to retrieve the path.

What other versions do you have installed?

ls -la /usr/bin/ might give you some more information.

You can also search for files with php in them using:
find / -type f -name "php"

You will probably see a whole lot of permision denied notices, hide them using:

find / -type f -name "php"   2>&1 | grep -v "Permission denied"

For me, this results in a nice list of PHP versions:

/opt/remi/php56/root/usr/bin/php
/opt/remi/php70/root/usr/bin/php
/opt/remi/php72/root/usr/bin/php
/opt/remi/php74/root/usr/bin/php
/opt/remi/php80/root/usr/bin/php
/opt/remi/php71/root/usr/bin/php
/opt/remi/php73/root/usr/bin/php

I can use any of this paths, to confirm it works we can run:

/opt/remi/php73/root/usr/bin/php -v

So, how do I make deployer use this?

In my case, I want to set the PHP version composer uses. We can set this by setting the bin/composer parameter in Deployer. Globally, by adding:

set('bin/composer',
	function () {
		return '/opt/remi/php73/root/usr/bin/php /usr/bin/composer';
	}
);

Or, per host, by adding:

host( 'prod' )
	->set(
		'bin/composer',
		function () {
			return '/opt/remi/php73/root/usr/bin/php /usr/bin/composer';
		}
	);

That’s it! Happy deploying!