Error message "Context was requested but was not available"

[acharseth]

I would like to do something like this in deploy.php:

<?php
namespace Deployer;

require 'recipe/laravel.php';
require 'contrib/rsync.php';

// Config
$host=currentHost()->getAlias();

// Common configurations:
set('rsync_src', "/tmp/myApp/$host");
...

But the $host=currentHost()->getAlias(); causes an error message: Context was requested but was not available.

How can I use the host-parameter in a set?

[antonmedv]

currentHost() only defined in tasks.

[acharseth]

Some other way I can get the host parameter?
I tried $host=$argv[2] but then get an error message saying that $argv is not defined.