Why isn't stdout set after executing a child process in a node.js script that's running as a daemon?

Question

This works as expected if I run it from the command line (node index.js). But when I execute this Node.js (v0.10.4) script as a daemon from a init.d script the stdout return value in the exec callback is not set. How do I fix this?

node.js script:

var exec = require('child_process').exec;
setInterval(function()
{
exec('get_switch_state', function(err, stdout, stderr) 
{
        if(stdout == "on")
        {
            // Do something.
        }
});
}, 5000);

init.d script:

#!/bin/bash

NODE=/development/nvm/v0.10.4/bin/node
SERVER_JS_FILE=/home/blahname/app/index.js
USER=root
OUT=/home/pi/nodejs.log

case "$1" in

start)
    echo "starting node: $NODE $SERVER_JS_FILE"
    sudo -u $USER $NODE $SERVER_JS_FILE > $OUT 2>$OUT &
    ;;

stop)
    killall $NODE
    ;;

*)
    echo "usage: $0 (start|stop)"
esac

exit 0

Answer 1

I ended up not using Node.js exec child_process. I modified the init.d script above (/etc/init.d/node-app.sh) as follows:

#!/bin/bash

NODE=/home/pi/development/nvm/v0.10.4/bin/node
SERVER_JS_FILE=/home/pi/development/mysql_test/index.js
USER=pi
OUT=/home/pi/development/mysql_test/nodejs.log

case "$1" in

start)
echo "starting node: $NODE $SERVER_JS_FILE"
sudo -u $USER TZ='PST' $NODE $SERVER_JS_FILE > $OUT 2>$OUT &
;;

stop)
killall $NODE
;;

*)
echo "usage: $0 (start|stop)"
esac

exit 0

This script launches the Node.js app "index.js" at boot up and everthing works as expected.