fix(launcher): handle ENOENT error, do not retry

If the binary does not exists:
- handle the error (Node 0.10+ throws unhandled error events)
- show nicer message
- do not retry

Closes #452

lib/launchers/Base.js

@@ -26,14 +26,14 @@ var BaseBrowser = function(id, emitter, captureTimeout, retryLimit) {
 
   this.start = function(url) {
     capturingUrl = url;
+    self.state = BEING_CAPTURED;
 
     try {
       log.debug('Creating temp dir at ' + self._tempDir);
       fs.mkdirSync(self._tempDir);
     } catch (e) {}
 
     self._start(capturingUrl + '?id=' + self.id);
-    self.state = BEING_CAPTURED;
 
     if (captureTimeout) {
       setTimeout(self._onTimeout, captureTimeout);
@@ -104,13 +104,35 @@ var BaseBrowser = function(id, emitter, captureTimeout, retryLimit) {
     self._process = spawn(cmd, args);
 
     var errorOutput = '';
-    self._process.stderr.on('data', function(data) {
-      errorOutput += data.toString();
-    });
 
     self._process.on('close', function(code) {
       self._onProcessExit(code, errorOutput);
     });
+
+    self._process.on('error', function(err) {
+      if (err.code === 'ENOENT') {
+        retryLimit = 0;
+        errorOutput = 'Can not find the binary ' + cmd + '\n\t' +
+                      'Please set env variable ' + self.ENV_CMD;
+      } else {
+        errorOutput += err.toString();
+      }
+    });
+
+    // Node 0.8 does not emit the error
+    if (process.versions.node.indexOf('0.8') === 0) {
+      self._process.stderr.on('data', function(data) {
+        var msg = data.toString();
+
+        if (msg.indexOf('No such file or directory') !== -1) {
+          retryLimit = 0;
+          errorOutput = 'Can not find the binary ' + cmd + '\n\t' +
+                        'Please set env variable ' + self.ENV_CMD;
+        } else {
+          errorOutput += msg;
+        }
+      });
+    }
   };
 
 

test/unit/launchers/Base.spec.coffee

@@ -32,6 +32,7 @@ describe 'launchers Base', ->
   globals =
     process:
       platform: 'darwin'
+      versions: node: '0.10.x'
       env:
         TMP: '/tmp'
       nextTick: process.nextTick
@@ -74,6 +75,30 @@ describe 'launchers Base', ->
       expect(browser._start).to.have.been.calledWith '/capture/url?id=123'
 
 
+    it 'should handle spawn ENOENT error and not even retry', (done) ->
+      browser = new m.BaseBrowser 123, new events.EventEmitter, 0, 3
+      browser.DEFAULT_CMD = darwin: '/usr/bin/browser'
+
+      error = new Error 'spawn ENOENT'
+      error.code = 'ENOENT'
+
+      browser.start '/capture/url'
+
+      spawnProcess = mockSpawn._processes[0]
+      mockSpawn.reset()
+
+      spawnProcess.emit 'error', error
+      spawnProcess.emit 'close', 1
+
+      # do not retry
+      expect(mockSpawn).not.to.have.been.called
+
+      browser.kill done
+
+      # do not kill already dead process
+      expect(spawnProcess.kill).to.not.have.been.called
+
+
   describe 'kill', ->
     it 'should just fire done if already killed', (done) ->
       browser = new m.BaseBrowser 123, new events.EventEmitter, 0, 1 # disable retry