What is npp_watcher

npp_watcher is a simple Node++ health checker.

We all care about our websites' reputation, and we want to make sure they're online always. Even expensive, reputable applications crash sometimes, or get killed by the system. We may be on a vacation on some remote island, enjoying our time away from the screen. When our web app is for whatever reason dead, we want it to be gracefully restarted. npp_watcher comes to the rescue.

Linux

Login as root, edit crontab (crontab -e) and add the command below:

NPP_DIR=<your NPP_DIR>

#-----------------------------------------------------------------------------
# min  hour day  month weekday command
#-----------------------------------------------------------------------------
# Node++ Watcher
  0,30 *    *    *     *       $NPP_DIR/bin/npp_watcher

This way npp_watcher will make an HTTP request every half an hour on the local HTTP port defined in npp.conf (or 80 if not defined). If it can't connect and get valid HTTP response in 60 seconds, Node++ will be restarted.

Parameters

There are a couple of parameters affecting npp_watcher that you can add to npp.conf:

Parameter	Description	Default
watcherLogLevel	Log level	0
watcherLogToStdout	Log to stdout	0
watcherLogRestart	Log level if restart is performed	3
watcherStartCmd	Start command	$NPP_DIR/bin/nppstart
watcherStopCmd	Stop command	$NPP_DIR/bin/nppstop
watcherWait	Wait between stop and start (in seconds)	10