Improve connection timeout. Solve race between closing connection on …

…timeout and log entry writing.

Simple approach - idle session is the one that is not used, despite the log success of failure.
Upon failure to log, always close the session.

lib/winston-mongodb.js

@@ -6,9 +6,9 @@
 *
 */
 
-var util = require('util'),
-    mongodb = require('mongodb'),
-    winston = require('winston');
+var util = require('util');
+var mongodb = require('mongodb');
+var winston = require('winston');
 
 //
 // ### function MongoDB (options)
@@ -82,10 +82,34 @@ MongoDB.prototype.log = function (level, msg, meta, callback) {
         return callback(err, null);
       }
 
+      // Set a timeout to close the client connection unless `self.keepAlive`
+      // has been set to true in which case it is the responsibility of the
+      // programmer to close the underlying connection.
+      if (self.timeout) {
+        if (self.timeoutId) {
+          clearTimeout(self.timeoutId);
+        }
+        self.timeoutId = setTimeout(function () {
+          // The session is idle. Closing it.
+          self.client.close();
+          self.state = 'unopened';
+        }, self.timeout);
+      }
+
+      function onError(err) {
+        self.emit('error', err);
+        if (self.timeoutId) {
+          clearTimeout(self.timeoutId);
+        }
+        // Next time try to open new session.
+        self.client.close();
+        self.state = 'unopened';
+        callback(err, null);
+      }
+
       self._db.collection(self.collection, function (err, col) {
         if (err) {
-          self.emit('error', err);
-          return callback(err, null);
+          return onError(err);
         }
 
         var entry = {
@@ -97,39 +121,17 @@ MongoDB.prototype.log = function (level, msg, meta, callback) {
 
         col.save(entry, { safe: self.safe }, function (err, doc) {
           if (err) {
-            self.emit('error', err);
-            return callback(err, null);
+            return onError(err);
           }
 
           self.emit('logged');
-          // Delay timeout to start from the last successful log.
-          self.setTimeout();
-          return callback(null, true);
+          callback(null, true);
         });
       });
     });
   });
 };
 
-MongoDB.prototype.setTimeout = function () {
-  var self = this;
-  if (!self.timeout) {
-    return;
-  }
-  if (self.timeoutId) {
-    clearTimeout(self.timeoutId);
-  }
-  //
-  // Set a timeout to close the client connection unless `self.keepAlive`
-  // has been set to true in which case it is the responsibility of the
-  // programmer to close the underlying connection.
-  //
-  self.timeoutId = setTimeout(function () {
-    self.client.close();
-    self.state = 'unopened';
-  }, self.timeout);
-}
-
 //
 // ### function open (callback)
 // #### @callback {function} Continuation to respond to when complete
@@ -186,7 +188,6 @@ MongoDB.prototype.open = function (callback) {
     self.state = 'opened';
     self._db = db;
     flushPending();
-    self.setTimeout();
   }
 
   self.state = 'opening';