fix: wait for all subprocesses to terminate (fixes issue #1476)

Author: marcelkottmann

Diff for: lib/monitor/run.js

@@ -16,6 +16,28 @@ var psTree = require('pstree.remy');
 var path = require('path');
 var signals = require('./signals');
 
+function waitForSubprocesses(subprocesses, callback) {
+  if (Array.isArray(subprocesses) && subprocesses.length > 0) {
+    // check if all old subprocesses have been terminated
+    exec('kill -0 ' + subprocesses.join(' '), (error) => {
+      const returnCode = error ? error.code : 0;
+      if (returnCode < 126) { // ignore command not found error
+        const stillRunning = subprocesses.length - returnCode;
+        if (stillRunning > 0) {
+          utils.log.status('still waiting for ' + stillRunning +
+            ' subprocess(es) to finish...');
+          setTimeout(waitForSubprocesses.bind(this, subprocesses, callback),
+            100);
+          return;
+        }
+      }
+      callback();
+    });
+  } else {
+    callback();
+  }
+}
+
 function run(options) {
   var cmd = config.command.raw;
 
@@ -341,17 +363,24 @@ function kill(child, signal, callback) {
     // configured signal (default: SIGUSR2) signal, which fixes #335
     // note that psTree also works if `ps` is missing by looking in /proc
     const sig = signal.replace('SIG', '');
-    psTree(child.pid, function (err, kids) {
+    psTree(child.pid, function (err, subprocesses) {
       if (psTree.hasPS) {
-        spawn('kill', ['-s', sig, child.pid].concat(kids))
-          .on('close', callback);
+        spawn('kill', ['-s', sig].concat(subprocesses))
+          .on('close', waitForSubprocesses.bind(this, subprocesses,
+            function () {
+              spawn('kill', ['-s', sig, child.pid])
+                .on('close', callback);
+            }));
       } else {
         // make sure we kill from smallest to largest
-        const pids = kids.concat(child.pid).sort();
+        const pids = subprocesses.slice().sort();
         pids.forEach(pid => {
           exec('kill -' + signals[signal] + ' ' + pid, () => { });
         });
-        callback();
+        waitForSubprocesses(subprocesses, function () {
+          exec('kill -' + signals[signal] + ' ' + child.pid, () => { });
+          callback();
+        })
       }
     });