Fixes the sniffOnConnectionFault config parameter

package.json

@@ -46,7 +46,7 @@
     "mocha-lcov-reporter": "0.0.1",
     "blanket": "~1.1.5",
     "sinon": "~1.7.3",
-    "nock": "0.27.0",
+    "nock": "git://github.com/spenceralger/nock#emit_stream_errors",
     "open": "0.0.4",
     "load-grunt-tasks": "~0.2.0",
     "load-grunt-config": "~0.7.0",

src/lib/connection_pool.js

@@ -200,7 +200,7 @@ ConnectionPool.prototype._onConnectionDied = function (connection, alreadyWasDea
 
   var ms = this.calcDeadTimeout(timeout.attempt, this.deadTimeout);
   timeout.id = setTimeout(timeout.revive, ms);
-  timeout.runAt = Date.now() + ms;
+  timeout.runAt = _.now() + ms;
 };
 
 ConnectionPool.prototype._selectDeadConnection = function (cb) {

src/lib/logger.js

@@ -168,7 +168,7 @@ LoggerAbstract.prototype._formatTraceMessage = function (req) {
 
 LoggerAbstract.prototype._prettyJson = function (body) {
   try {
-    if (typeof object === 'string') {
+    if (typeof body === 'string') {
       body = JSON.parse(body);
     }
     return JSON.stringify(body, null, '  ').replace(/'/g, '\\u0027');

src/lib/transport.js

@@ -8,6 +8,7 @@ var _ = require('./utils');
 var errors = require('./errors');
 var Host = require('./host');
 var Promise = require('bluebird');
+var patchSniffOnConnectionFault = require('./transport/sniff_on_connection_fault');
 
 function Transport(config) {
   var self = this;
@@ -80,7 +81,9 @@ function Transport(config) {
     }, config.sniffInterval);
   }
 
-  this.sniffAfterConnectionFault = config.sniffAfterConnectionFault;
+  if (config.sniffOnConnectionFault) {
+    patchSniffOnConnectionFault(this);
+  }
 }
 
 Transport.connectionPools = {
@@ -116,7 +119,6 @@ Transport.prototype.defer = function () {
  * @param {Function} cb - A function to call back with (error, responseBody, responseStatus)
  */
 Transport.prototype.request = function (params, cb) {
-
   var self = this;
   var remainingRetries = this.maxRetries;
   var requestTimeout = this.requestTimeout;

src/lib/transport/sniff_on_connection_fault.js

@@ -0,0 +1,59 @@
+var _ = require('../utils');
+
+
+/**
+ * Patch the transport's connection pool to schedule a sniff after a connection fails.
+ * When a connection fails for the first time it will schedule a sniff 1 second in the
+ * future, and increase the timeout based on the deadTimeout algorithm chosen by the
+ * connectionPool, and the number of times the sniff has failed.
+ *
+ * @param  {Transport} transport - the transport that will be using this behavior
+ * @return {undefined}
+ */
+module.exports = function setupSniffOnConnectionFault(transport) {
+  var failures = 0;
+  var pool = transport.connectionPool;
+  var originalOnDied = pool._onConnectionDied;
+
+  // do the actual sniff, if the sniff is unable to
+  // connect to a node this function will be called again by the connectionPool
+  var work = function () {
+    work.timerId = transport._timeout(work.timerId);
+    transport.sniff();
+  };
+
+  // create a function that will count down to a
+  // point n milliseconds into the future
+  var countdownTo = function (ms) {
+    var start = _.now();
+    return function () {
+      return start - ms;
+    };
+  };
+
+  // overwrite the function, but still call it
+  pool._onConnectionDied = function (connection, wasAlreadyDead) {
+    var ret = originalOnDied.call(pool, connection, wasAlreadyDead);
+
+    // clear the failures if this is the first failure we have seen
+    failures = work.timerId ? failures + 1 : 0;
+
+    var ms = pool.calcDeadTimeout(failures, 1000);
+
+    if (work.timerId && ms < work.timerId && work.countdown()) {
+      // clear the timer
+      work.timerId = transport._timeout(work.timerId);
+    }
+
+    if (!work.timerId) {
+      work.timerId = transport._timeout(work, ms);
+      work.countdown = countdownTo(ms);
+    }
+
+    return ret;
+  };
+
+  pool._onConnectionDied.restore = function () {
+    pool._onConnectionDied = originalOnDied;
+  };
+};

src/lib/utils.js

@@ -418,4 +418,11 @@ _.getUnwrittenFromStream = function (stream) {
   }
 };
 
+/**
+ * return the current time in milliseconds since epoch
+ */
+_.now = function () {
+  return (typeof Date.now === 'function') ? Date.now() : (new Date()).getTime();
+};
+
 module.exports = utils;

test/unit/specs/transport_with_server.js

@@ -1,10 +1,12 @@
 var Transport = require('../../../src/lib/transport');
+var ConnectionPool = require('../../../src/lib/connection_pool');
 var Host = require('../../../src/lib/host');
 var errors = require('../../../src/lib/errors');
 var expect = require('expect.js');
 
 var sinon = require('sinon');
 var nock = require('../../mocks/server.js');
+var estr = require('event-stream');
 var _ = require('lodash-node');
 var nodeList = require('../../fixtures/short_node_list.json');
 var stub = require('../../utils/auto_release_stub').make();
@@ -302,5 +304,46 @@ describe('Transport + Mock server', function () {
         });
       });
     });
+
+    describe('sniffOnConnectionFault', function () {
+      it('schedules a sniff when sniffOnConnectionFault is set and a connection failes', function (done) {
+        var clock = sinon.useFakeTimers('setTimeout');
+        var serverMock = nock('http://esbox.1.com')
+          .get('/')
+          .reply(200, function () {
+            var str = estr.readable(function (count, cb) {
+              cb(new Error('force error'));
+            });
+            str.setEncoding = function () {}; // force nock's isStream detection
+            return str;
+          });
+
+        stub(ConnectionPool.prototype, '_onConnectionDied');
+        stub(Transport.prototype, 'sniff');
+        var tran = new Transport({
+          hosts: 'http://esbox.1.com',
+          sniffOnConnectionFault: true,
+          maxRetries: 0
+        });
+
+        expect(tran.connectionPool._onConnectionDied).to.not.be(ConnectionPool.prototype._onConnectionDied);
+
+        tran.request({
+          requestTimeout: Infinity
+        }).then(
+          _.partial(done, new Error('expected the request to fail')),
+          function (err) {
+            expect(ConnectionPool.prototype._onConnectionDied.callCount).to.eql(1);
+            expect(tran.sniff.callCount).to.eql(0);
+            expect(_.size(clock.timeouts)).to.eql(1);
+            var timeout = _.values(clock.timeouts).pop();
+            timeout.func();
+            expect(tran.sniff.callCount).to.eql(1);
+            clock.restore();
+            done();
+          }
+        );
+      });
+    });
   });
 });