Spawn a process and restart it if it crashes. Specific for jsonar's SonarK product.
npm install respawn
It is easy to use
var respawn =var monitor =monitorstart // spawn and watch
Optionally you can specify the command to to spawn in the option map as
Per default respawn will restart you app indefinitely. To set a max restart limit set the
sleep is an array of numbers it will use the value at the position of the current number of restarts as the timeout value. If the number of restarts exceed the length of the array it will use the last value in the array until it hits the maxRestarts.
sleep: [1000, 60000, 60000, 12000, 1000] will wait 1000ms before retrying, then it will wait 60000 before the next retry and so forth.
sleep is a function it will be passed the number of times (including this one) that the app has been restarted (i.e. first time will be called with 1, second time 2 etc.) and should return a time in milliseconds.
monitor.start()Starts the monitor
monitor.stop(cb)Stops the monitor (kills the process if its running with SIGTERM)
monitor.statusGet the current monitor status. Available values are
monitor.on('start')The monitor has started
monitor.on('stop')The monitor has fully stopped and the process is killed
monitor.on('crash')The monitor has crashed (too many restarts or spawn error).
monitor.on('sleep')monitor is sleeping
monitor.on('spawn', process)New child process has been spawned
monitor.on('exit', code, signal)child process has exited
monitor.on('stdout', data)child process stdout has emitted data
monitor.on('stderr', data)child process stderr has emitted data
monitor.on('warn', err)child process has emitted an error
To do graceful restart simply have your app stop gracefully when receiving
SIGTERM and do
// graceful restart (do not wait for old process to die)monitormonitorstart// hard restart (wait for old process to die)monitor