全局环境变量不适用于在PHP中执行的bash命令

Question

I'm trying to return the value of a global environment variable inside a bash script which is executed from inside PHP (run as sudo).

Running the command printenv from the bash script reveals that the global variable is not set. I understand sudo resets the environment.

Please consider the following setup;

Define global environment var

root@test:/# export HEY=hello

Test existence of var

root@test:/# printenv | grep HEY
HEY=hello

Please consider this PHP function

PHP function

function testAction() {

    define('TEST_CMD', '/usr/bin/sudo /usr/local/test/bin/');
    $command = 'bash_script';
    $query = TEST_CMD.$command;

    exec ($query, $output, $return_var);

    var_dump( $output );
    var_dump( $return_var );
    echo exec('whoami');

}

Contents of /etc/sudoers.d/admin

admin   ALL=(ALL)       ALL
admin   ALL=NOPASSWD:/usr/local/test/bin/*

Contents of /usr/local/test/bin/bash_script

#!/bin/bash
printenv
echo $HEY
exit

I have tried putting Defaults env_keep +="HEY" inside /etc/sudoers.d/admin too but that doesn't appear to work either.

OS is ubuntu 14.04

Any ideas?