fix: wait for _all_ child processes to terminate (fixes issue #1476)

Author: marcelkottmann

Diff for: lib/monitor/run.js

@@ -15,6 +15,28 @@ var restart = null;
 var psTree = require('pstree.remy');
 var path = require('path');
 var signals = require('./signals');
+var oldKids;
+
+function waitForOldKids(callback) {
+  if (oldKids) {
+    // check if all previous kids have been terminated
+    exec('kill -0  ' + oldKids.join(' '), (error) => {
+      const returnCode = error ? error.code : 0;
+      if (returnCode < 126) { // ignore command not found error
+        const stillRunningKids = oldKids.length - returnCode;
+        if (stillRunningKids > 0) {
+          utils.log.status('still waiting for ' + stillRunningKids +
+            ' child process(es) to finish...');
+          setTimeout(waitForOldKids.bind(this, callback), 100);
+          return;
+        }
+      }
+      callback();
+    });
+  } else {
+    callback();
+  }
+}
 
 function run(options) {
   var cmd = config.command.raw;
@@ -25,7 +47,14 @@ function run(options) {
   }
 
   /*jshint validthis:true*/
-  restart = run.bind(this, options);
+  var runbinded = run.bind(this, options);
+
+  if (utils.isWindows) {
+    restart = runbinded;
+  } else {
+    restart = waitForOldKids.bind(this, runbinded);
+  }
+
   run.restart = restart;
 
   config.lastStarted = Date.now();
@@ -80,7 +109,7 @@ function run(options) {
   var inBinPath = false;
   try {
     inBinPath = statSync(`${binPath}/${executable}`).isFile();
-  } catch (e) {}
+  } catch (e) { }
 
   // hasStdio allows us to correctly handle stdin piping
   // see: https://git.io/vNtX3
@@ -342,6 +371,7 @@ function kill(child, signal, callback) {
     // note that psTree also works if `ps` is missing by looking in /proc
     const sig = signal.replace('SIG', '');
     psTree(child.pid, function (err, kids) {
+      oldKids = kids;
       if (psTree.hasPS) {
         spawn('kill', ['-s', sig, child.pid].concat(kids))
           .on('close', callback);