fix socket issues

Author: jamiees2

lib/sender.js

@@ -299,8 +299,20 @@ class FluentSender {
     if (this._status === 'established') {
       return;
     }
+    if (!this._socket) {
+      const error = new FluentLoggerError.HandshakeError('socket went away before handshake');
+      this._handleEvent('error', error);
+      this._disconnect();
+      return;
+    }
     this._status = 'helo';
     this._socket.once('data', (data) => {
+      if (!this._socket) {
+        const error = new FluentLoggerError.HandshakeError('socket went away during handshake');
+        this._handleEvent('error', error);
+        this._disconnect();
+        return;
+      }
       this._socket.pause();
       const heloStatus = this._checkHelo(data);
       if (!heloStatus.succeeded) {
@@ -310,6 +322,12 @@ class FluentSender {
       }
       this._status = 'pingpong';
       this._socket.write(this._generatePing(), () => {
+        if (!this._socket) {
+          const error = new FluentLoggerError.HandshakeError('socket went away during ping');
+          this._handleEvent('error', error);
+          this._disconnect();
+          return;
+        }
         this._socket.resume();
         this._socket.once('data', (data) => {
           const pongStatus = this._checkPong(data);
@@ -406,33 +424,40 @@ class FluentSender {
     const sendPacketSize = (options && options.eventEntryDataSize) || this._sendQueueSize;
     this._socket.write(packet, () => {
       if (this.requireAckResponse) {
-        this._socket.once('data', (data) => {
-          timeoutId && clearTimeout(timeoutId);
-          const response = msgpack.decode(data, { codec: codec });
-          if (response.ack !== options.chunk) {
-            const error = new FluentLoggerError.ResponseError(
-              'ack in response and chunk id in sent data are different',
-              { ack: response.ack, chunk: options.chunk }
-            );
-            callbacks.forEach((callback) => {
-              this._handleEvent('error', error, callback);
-            });
-          } else { // no error on ack
-            callbacks.forEach((callback) => {
-              callback && callback();
-            });
-          }
-          this._sendQueueSize -= sendPacketSize;
-          process.nextTick(() => {
-            this._waitToWrite();
-          });
-        });
-        timeoutId = setTimeout(() => {
-          const error = new FluentLoggerError.ResponseTimeout('ack response timeout');
+        if (!this._socket) {
+          const error = new FluentLoggerError.ResponseError('server went away');
           callbacks.forEach((callback) => {
             this._handleEvent('error', error, callback);
           });
-        }, this.ackResponseTimeout);
+        } else {
+          this._socket.once('data', (data) => {
+            timeoutId && clearTimeout(timeoutId);
+            const response = msgpack.decode(data, { codec: codec });
+            if (response.ack !== options.chunk) {
+              const error = new FluentLoggerError.ResponseError(
+                'ack in response and chunk id in sent data are different',
+                { ack: response.ack, chunk: options.chunk }
+              );
+              callbacks.forEach((callback) => {
+                this._handleEvent('error', error, callback);
+              });
+            } else { // no error on ack
+              callbacks.forEach((callback) => {
+                callback && callback();
+              });
+            }
+            this._sendQueueSize -= sendPacketSize;
+            process.nextTick(() => {
+              this._waitToWrite();
+            });
+          });
+          timeoutId = setTimeout(() => {
+            const error = new FluentLoggerError.ResponseTimeout('ack response timeout');
+            callbacks.forEach((callback) => {
+              this._handleEvent('error', error, callback);
+            });
+          }, this.ackResponseTimeout);
+        }
       } else {
         this._sendQueueSize -= sendPacketSize;
         callbacks.forEach((callback) => {