pm2-interface

Interact with pm2 via RPC and receive real time notifications

npm install pm2-interface
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pm2-interface (for pm2 version >= 0.6.0)

pm2-interface permits you to interact with PM2 the process manager for NodeJS.

You can control all exposed methods by the pm2 deamon God and also receive real time notifications for example for a process who got an unexpectedException, who's starting/stopping.

RPC methods

  • ipm2.rpc.prepareJson(json_app, cwd, fn) send a JSON configuration to start app(s) in the cwd folder
  • ipm2.rpc.getMonitorData({}, fn) receive all related informations about supervised process (cpu/ram/pid...)
  • ipm2.rpc.getSystemData({}, fn) receive all data about process managed by pm2 and computer resources usage
  • ipm2.rpc.startProcessId(integer, fn) start a process by id (pm_id) who his state is stopped
  • ipm2.rpc.stopProcessId(integer, fn) stop a process by id (pm_id)
  • ipm2.rpc.stopAll({}, fn) stop all process
  • ipm2.rpc.reload(data, fn) reload all apps (only for networked apps)
  • ipm2.rpc.killMe(data, fn) kill pm2 daemon
  • ipm2.rpc.findByScript(string, fn) send you back the informations about a specific process
  • ipm2.rpc.restartProcessId(integer, fn) restart a process by id (pm_id)
  • ipm2.rpc.restartProcessName(string, fn) restart all processes who have the given name
  • ipm2.rpc.deleteProcess(string, fn) stop and delete all processes from the pm2 database
  • ipm2.rpc.deleteAll(data, fn) stop and delete all processes
  • ipm2.rpc.msgProcess(opts, fn) send msg opts.msg to process at opts.id or all processes with opts.name

Notifications

  • process:online when a process is started/restarted
  • process:exit when a process is exited
  • process:exception When a process has received an uncaughtException

Advanced feature : You can use process.send({ type : 'my:message', data : {}}) in your Node apps. When you emit a message, they will be redirected to pm2 and sent back to the pm2-interface bus. This can be coupled with rpc.msgProcess(opts, fn) to allow 2-way communication between managed processes and pm2-interface - see second Example below.

It should be noted that process.send will be undefined if there is no parent process. Therefore a check of if (process.send) may be advisable.

Example

var ipm2 = require('pm2-interface')();

ipm2.on('ready', function() {
  console.log('Connected to pm2');

  ipm2.bus.on('*', function(event, data){
    console.log(event, data.pm2_env.name);
  });

  setTimeout(function() {
    ipm2.rpc.restartProcessId(0, function(err, dt) {
      console.log(dt);
    });
  }, 2000);


  ipm2.rpc.getMonitorData({}, function(err, dt) {
    console.log(dt);
  });
});

Example 2-way

in your process script

if (send in process) {
  process.on("message", function (msg) {
    if ( "type" in msg && msg.type === "god:heap" ) {
        var heap = process.memoryUsage().heapUsed
      process.send({type:"process:heap", heap:heap})
    }
  })
}

var myMemoryLeak = []

setInterval( function () {
  var object = {}
  for (var i = 0; i < 10000; i++) {
    object["key"+i] = Math.random().toString(36).substring(7)
  }

  myMemoryLeak.push(object)

}, Math.round(Math.random()*2000))

in monitoring script

var ipm2 = require('pm2-interface')()

ipm2.on('ready', function() {

    console.log('Connected to pm2')

    ipm2.bus.on('process:heap', function(data){
        console.log("process heap:", data)
    })


    setInterval( function () {
        var msg = {type:"god:heap"}   // god: is arbitrary and used to distinguish incoming & outgoing msgs
        ipm2.rpc.msgProcess({name:"worker", msg:msg}, function (err, res) {
            if (err) console.log(err)
            else console.log(res)
        })
    }, 5000)
})

Start pm2 and monitoring script + output:

pm2 start worker.js -i 3 --name worker
node monitor.js

sent 3 messages   # coming from the console.log(res)
process heap: { pm_id: 0, msg: { type: 'process:heap', heap: 43416064 } }
process heap: { pm_id: 1, msg: { type: 'process:heap', heap: 18373704 } }
process heap: { pm_id: 2, msg: { type: 'process:heap', heap: 80734256 } }
sent 3 messages
process heap: { pm_id: 0, msg: { type: 'process:heap', heap: 61994096 } }
process heap: { pm_id: 1, msg: { type: 'process:heap', heap: 22437400 } }
process heap: { pm_id: 2, msg: { type: 'process:heap', heap: 116622432 } }
sent 3 messages
process heap: { pm_id: 0, msg: { type: 'process:heap', heap: 79641168 } }
process heap: { pm_id: 1, msg: { type: 'process:heap', heap: 32260112 } }
process heap: { pm_id: 2, msg: { type: 'process:heap', heap: 156047904 } }

pm2 delete all

Disconnect

Since pm2-interface interacts with PM2 via sockets, any script which uses pm2-interface will remain alive even when the node.js event loop is empty. process.exit() can be called to forcefully exit, or, if your script has finished making calls to PM2, you may call ipm2.disconnect() to disconnect the socket connections and allow node to exit automatically.

ipm2.on('ready', function() {

  // ...

  ipm2.disconnect();
});

Calling disconnect() means "I am entirely done interacting with PM2." You will no longer be able to receive messages on ipm2.bus or send requests on ipm2.rpc. To reconnect you must completely start over with a new ipm2 object.

Ideas

  • Catching exceptions and fowarding them by mail
  • A web interface to control PM2

Apache v2 License

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