Simple snippet for cross-platform .pid management in NodeJS. I use it for managing NodeJS apps with supervisord and monit

pid.js

//
// Usage: require('./pid')("myapp");
//
var fs        = require('fs');

module.exports = function(appname){
  process.title = appname;

  var PID_FILE  = "/usr/local/var/run/"+process.title+".pid";

  fs.writeFileSync(PID_FILE, process.pid+"\n");

  process.on("uncaughtException", function(err) {
    console.error("[uncaughtException]", err);
    return process.exit(1);
  });

  process.on("SIGTERM", function() {
    console.log("SIGTERM (killed by supervisord or another process management tool)");
    return process.exit(0);
  });

  process.on("SIGINT", function() {
    console.log("SIGINT");
    return process.exit(0);
  });

  process.on("exit", function() {
    return fs.unlink(PID_FILE);
  });
  
};

pid_management.coffee

#
# The following snippet must be inserted at the top of your main js file
#

process.title = "MyApp"
PID_FILE      = "/usr/local/var/run/#{process.title}.pid"
fs            = require("fs")

fs.writeFileSync PID_FILE, "#{process.pid}\n"

process.on "uncaughtException", (err) ->
  console.error "[uncaughtException]", err
  process.exit 1

process.on "SIGTERM", ->
  console.log "SIGTERM (killed by supervisord or another process management tool)"
  process.exit 0

process.on "SIGINT", ->
  console.log "SIGINT"
  process.exit 0

process.on "exit", ->
  console.log('Exiting...')
  fs.unlink PID_FILE

#
# Your code start here
#

setInterval (->), 1000

pid_management.js

//
// The following snippet must be inserted at the top of your main js file
//

process.title = "MyApp";

var PID_FILE  = "/usr/local/var/run/"+process.title+".pid"
,   fs        = require('fs');

fs.writeFileSync(PID_FILE, process.pid+"\n");

process.on("uncaughtException", function(err) {
  console.error("[uncaughtException]", err);
  return process.exit(1);
});

process.on("SIGTERM", function() {
  console.log("SIGTERM (killed by supervisord or another process management tool)");
  return process.exit(0);
});

process.on("SIGINT", function() {
  console.log("SIGINT");
  return process.exit(0);
});

process.on("exit", function() {
  return fs.unlink(PID_FILE);
});

//
// Your code start here
//

setInterval(function(){}, 1000);

You should use the unlinkSync on exit, otherwise you'll not granted to have the pid file deleted

You should use the unlinkSync on exit, otherwise you'll not granted to have the pid file deleted