Use tree-kill on exit to kill process trees spawned by children

lib/Spawn.js

@@ -1,4 +1,5 @@
-var spawn = require('child_process').spawn;
+var childProcess = require('child_process');
+var path = require('path');
 
 function Spawn(stream, command, args, name, output) {
   var exited = false;
@@ -13,7 +14,7 @@ function Spawn(stream, command, args, name, output) {
     };
   }
 
-  spawnedProcess = spawn(command, args, options);
+  spawnedProcess = childProcess.spawn(command, args, options);
 
   this.id = name;
 
@@ -52,7 +53,12 @@ function Spawn(stream, command, args, name, output) {
 
   process.on('exit', function(code) {
     if (exited === false) {
-      spawnedProcess.kill();
+      // 'exit' callback cannot perform asynchronous work
+      // therefore run standalone-treekill in a subprocess using spawnSync.
+      // assuming standalone-treekill.js in same directory as Spawn.js
+      var treeKillScriptPath = path.resolve(__dirname, 'standalone-treekill.js');
+      var spawnOptions = { stdio: 'inherit' };
+      childProcess.spawnSync(process.execPath, [treeKillScriptPath, spawnedProcess.pid], spawnOptions);
     }
   });
 

lib/standalone-treekill.js

@@ -0,0 +1,9 @@
+var treeKill = require('tree-kill');
+
+var processID = parseInt(process.argv[2]);
+
+treeKill(processID, function(err) {
+  if (err) {
+    console.error(err.stack || err);
+  }
+});

package.json

@@ -41,6 +41,7 @@
     "keypress": "0.2.1",
     "protogram": "1.1.3",
     "protogram-help": "1.0.2",
+    "tree-kill": "1.2.1",
     "unparse-args": "1.0.1"
   },
   "devDependencies": {