conn.write callback for buffer drain event (#132)

* conn.write callback for buffer drain event

* version bump

README.md

@@ -187,19 +187,18 @@ These are events inherited from `Writable`.
 DEPRECATED. Use `buffer drain` event instead.
 
 #### `'buffer drain'`
-This event is emitted when the underlying ring buffer is fully consumed and becomes empty.
+This event is emitted when the underlying ring buffer is fully consumed and Socket.write callback called.
 This can be useful when it’s time for the application to terminate but you want
 to be sure any pending logs have finished writing.
 
 ```javascript
 process.on('SIGINT', () => {
    logger.notice({ type: 'server', event: 'shutdown' });
    logger.once('buffer drain', () => {
-        logger.end(() => {
-            setTimeout(() => {
-                process.exit(0);
-            }, 2000); // this delay gives sometime for the underlying connection to flush its queue
-        });
+      logger.closeConnection();
+      logger.on('disconnected', () => {
+        process.exit();
+      });
    });
 });
 ```

package.json

@@ -1,6 +1,6 @@
 {
   "name": "le_node",
-  "version": "1.6.4",
+  "version": "1.6.5",
   "description": "Logentries client for node; use with or without Winston or Bunyan.",
   "keywords": [
     "logentries",

src/logger.js

@@ -166,6 +166,10 @@ class Logger extends Writable {
     this.ringBuffer.on('buffer shift', () => {
       this.debugLogger.log('Buffer is full, will be shifting records until buffer is drained.');
     });
+
+    this.on('buffer drain', () => {
+      this.debugLogger.log('RingBuffer drained.');
+    });
   }
 
   /**
@@ -177,14 +181,19 @@ class Logger extends Writable {
     this.connection.then(conn => {
       const record = this.ringBuffer.read();
       if (record) {
-        conn.write(record);
         // we are checking the buffer state here just after conn.write()
         // to make sure the last event is sent to socket.
         if (this.ringBuffer.isEmpty()) {
-          this.emit('buffer drain');
-          // this event is DEPRECATED - will be removed in next major release.
-          // new users should use 'buffer drain' event instead.
-          this.emit('connection drain');
+          conn.write(record, () => {
+            process.nextTick(() => {
+              this.emit('buffer drain');
+              // this event is DEPRECATED - will be removed in next major release.
+              // new users should use 'buffer drain' event instead.
+              this.emit('connection drain');
+            });
+          });
+        } else {
+          conn.write(record);
         }
       } else {
         this.debugLogger.log('This should not happen. Read from ringBuffer returned null.');
@@ -309,6 +318,7 @@ class Logger extends Writable {
   closeConnection() {
     this.debugLogger.log('Closing retry mechanism along with its connection.');
     if (!this.reconnection) {
+      this.debugLogger.log('No reconnection instance found. Returning.');
       return;
     }
     // this makes sure retry mechanism and connection will be closed.
@@ -373,7 +383,6 @@ class Logger extends Writable {
       this.reconnection.on('connect', (connection) => {
         this.debugLogger.log('Connected');
         this.emit('connected');
-        resolve(connection);
 
         // connection listeners
         connection.on('timeout', () => {
@@ -385,6 +394,7 @@ class Logger extends Writable {
           this.connection = null;
           this.emit('timed out');
         });
+        resolve(connection);
       });
 
       this.reconnection.on('reconnect', (n, delay) => {