Return error on getStats if Redis client is undefined

Currently when calling getStats, if the first sync call has not been
made yet, an 'cannot get value of undefined' error will be thrown.

This adds an error message explaining that the client is not
initialised and that an initial sync is required.

lib/sync-metrics.js

@@ -148,28 +148,33 @@ var getStats = function(cb) {
       return input.toFixed(2) + 'ms';
     }
   }];
-  async.map(metricsToFetch, function(metric, callback) {
-    var metricName = metric.metricName;
-    redisClient.lrange([statsNamespace, metricName].join(':'), 0, MAX_NUMBER, function(err, data) {
+  if (redisClient) {
+    async.map(metricsToFetch, function(metric, callback) {
+      var metricName = metric.metricName;
+      redisClient.lrange([statsNamespace, metricName].join(':'), 0, MAX_NUMBER, function(err, data) {
+        if (err) {
+          debugError('Failed to get values from redis for key %s  with error : %s', metricName, err);
+          return callback();
+        }
+        var stats = aggregateData(metric, data);
+        stats.name = metric.displayName;
+        return callback(null, stats)
+      });
+    }, function(err, results) {
       if (err) {
-        debugError('Failed to get values from redis for key %s  with error : %s', metricName, err);
-        return callback();
+        return cb(err);
       }
-      var stats = aggregateData(metric, data);
-      stats.name = metric.displayName;
-      return callback(null, stats)
+      var reduced = _.reduce(results, function(sofar, result) {
+        sofar[result.name] = result;
+        delete result.name;
+        return sofar;
+      }, {});
+      return cb(null, reduced);
     });
-  }, function(err, results) {
-    if (err) {
-      return cb(err);
-    }
-    var reduced = _.reduce(results, function(sofar, result) {
-      sofar[result.name] = result;
-      delete result.name;
-      return sofar;
-    }, {});
-    return cb(null, reduced);
-  });
+  } else {
+    var redisClientError = new Error('Redis client is not initialised. An initial sync may not have been performed yet.');
+    return cb(redisClientError);
+  }
 };
 
 module.exports = {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "fh-sync",
-  "version": "1.0.9",
+  "version": "1.0.10",
   "description": "FeedHenry Data Synchronization Server",
   "main": "index.js",
   "dependencies": {