Issue #61: Analyse what is preventing process to exit

- Close ports explicitely.
- Log pending handlers and requests in the Event Loop.
  Reference:
  nodejs/node#1128
  https://github.com/thlorenz/active-handles

iCubTelemVizServer/iCubTelemVizServer.js

@@ -84,6 +84,7 @@ const TerminationHandler = require('./terminationHandler.js');
 
 Object.keys(portInConfig).forEach(function (id) {
     var portIn = yarp.portHandler.open(portInConfig[id]["localName"],portInConfig[id]["portType"]);
+    TerminationHandler.prototype.closeNetworkPorts.push(() => {yarp.portHandler.close(portInConfig[id]["localName"])});
 
     // Redefine the Yarp port listener
     switch (portInConfig[id]["portType"]) {
@@ -109,6 +110,7 @@ icubtelemetry.startNotifier();
 
 // Create RPC server for executing system commands
 portRPCserver4sysCmds = yarp.portHandler.open('/yarpjs/sysCmdsGenerator/rpc','rpc');
+TerminationHandler.prototype.closeNetworkPorts.push(() => {yarp.portHandler.close('/yarpjs/sysCmdsGenerator/rpc')});
 
 portRPCserver4sysCmds.onRead(function (cmdNparams) {
     var cmdArray = cmdNparams.toArray();

iCubTelemVizServer/terminationHandler.js

@@ -22,7 +22,8 @@ TerminationHandler.prototype.run = function(signal) {
     Promise.all([subsetCpromise,subsetApromise.closeServers]).then(
         function(values) {
           values.forEach((v) => console.log(v));
-          process.exit();
+          // console.log(process._getActiveHandles());
+          console.log(process._getActiveRequests());
         }
       ).catch(console.error);
 }
@@ -79,6 +80,8 @@ TerminationHandler.prototype.runSubsetB = function(resValue) {
      console.log('iCub Telemetry Server closing: no further "subscribe"/"unsubscribe" requests accepted.');
      this.unlistenToNetworkPorts.forEach((disconnect) => { disconnect(); }); // Disconnect all telemetry entries (asynch operation)
      console.log('iCub Telemetry Server closing: disconnected network ports.');
+     this.closeNetworkPorts.forEach((closePort) => { closePort(); }); // Close all network ports (asynch operation)
+     console.log('iCub Telemetry Server closing: closed network ports.');
      this.icubtelemetry.stopNotifier();
      return Promise.resolve('Data transmission ended.');
 }
@@ -97,4 +100,6 @@ TerminationHandler.prototype.runSubsetC = function(resValue) {
 
 TerminationHandler.prototype.unlistenToNetworkPorts = [];
 
+TerminationHandler.prototype.closeNetworkPorts = [];
+
 module.exports = TerminationHandler;