Automatically install wp-cli on first connection

pre-ssh.php

<?php
/**
 * Automatically install wp-cli on remote hosts if absent
 *
 * @author koko-ng <koko@kokong.info>
 * @package koko-ng/wp-cli-config
 */

WP_CLI::add_hook(
	'before_ssh',
	function () {

		$host   = WP_CLI\Utils\parse_ssh_url(
			WP_CLI::get_runner()->config['ssh'],
			PHP_URL_HOST
		);
		$scheme = WP_CLI\Utils\parse_ssh_url(
			WP_CLI::get_runner()->config['ssh'],
			PHP_URL_SCHEME
		);
		// Default home in docker images is /var/www.
		if ( 'docker' === $scheme ) {
			$home = '/tmp';
		} else {
			$home = '$HOME';
		}
		
		putenv(
			sprintf(
				'WP_CLI_SSH_PRE_CMD=[ ! -f "%1$s/.bin/wp" ] && (mkdir -p %1$s/.bin; cd %1$s/.bin/; curl -o wp https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar; chmod +x %1$s/.bin/wp); export PATH=%1$s/.bin/:$PATH',
				$home
			)
		);
	}
);

Automatically install wp-cli on remote host

wp-cli is installed and added to path if it isn't available.

Installation

Save the above file in ~/.wp-cli/
In ~/.wp-cli/config.yml put

require:
  - pre-ssh.php