Code to plug in wp-config.php before any constants are defined, so that wp-cli doesnt throw any errors as $_SERVER wouldn't be available when running a wp-cli script

wp-config.php

<?php

//initial code to set error reporting, xdebug customization etc.

if ( defined('WP_CLI') && WP_CLI ) {
	if( empty( WP_CLI::get_runner()->config['url'] ) ) {
		error_log( "You need to set url." );
		exit;
	}

	$_SERVER['SERVER_NAME'] = 'http://' . str_replace( array( 'https://', 'http://' ), '', WP_CLI::get_runner()->config['url'] );

	$_SERVER['SERVER_NAME'] = parse_url( $_SERVER['SERVER_NAME'], PHP_URL_HOST );

	if( empty( $_SERVER['SERVER_NAME'] ) ) {
		error_log( "You need to set a site url." );
		exit;
	}

	$_SERVER['HTTP_USER_AGENT'] = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.57 Safari/537.36';
}


define('WP_SITEURL', 'http://' . $_SERVER['SERVER_NAME']);

// rest of the stuff