asyncTimer

lib/statsFunctions.js

@@ -48,6 +48,42 @@ function applyStatsFns (Client) {
     };
   };
 
+  /**
+   * Decorates an async function with timing recording behaviour.
+   *
+   * This version of `timer` will record the time take for the asyncronus action returned by `func`
+   * not just the execution time of `func` itself.
+   *
+   * @param func {<T,A>(...A):Promise<T>} The function to run
+   * @param stat {String|Array} The stat(s) to send
+   * @param sampleRate {Number=} The Number of times to sample (0 to 1). Optional.
+   * @param tags {Array=} The Array of tags to add to metrics. Optional.
+   * @param callback {Function=} Callback when message is done being delivered. Optional.
+   */
+  Client.prototype.asyncTimer = function (func, stat, sampleRate, tags, callback) {
+    var self = this;
+    return function() {
+      var end = hrtimer();
+      var p = func.apply(null, arguments);
+      var recordStat = function() { self.timing(stat, end(), sampleRate, tags, callback); };
+      p.then(recordStat, recordStat);
+      return p;
+    };
+  };
+
+  function hrtimer() {
+    var start = process.hrtime();
+
+    return function () {
+      var durationComponents = process.hrtime(start);
+      var seconds = durationComponents[0];
+      var nanoseconds = durationComponents[1];
+      var duration = seconds * 1000 + nanoseconds / 1E6;
+      return duration;
+    };
+  }
+
+
   /**
    * Increments a stat by a specified amount
    * @param stat {String|Array} The stat(s) to send
@@ -267,4 +303,4 @@ function applyStatsFns (Client) {
   };
 }
 
-module.exports = applyStatsFns;
+module.exports = applyStatsFns;

test/timer.js

@@ -1,5 +1,5 @@
 'use strict';
-
+var StatsD = require('../lib/statsd');
 var assert = require('assert');
 
 var createStatsdClient = require('./helpers').createStatsdClient;
@@ -105,5 +105,32 @@ module.exports = function runTimerTestSuite() {
         });
       });
     });
+
+    it('should record "user time" of promise', function () {
+      /* globals Promise */
+      var statsd = new StatsD({mock:true});
+
+      var onehundredMsFunc = function () { return delay(100); };
+
+      var instrumented = statsd.asyncTimer(onehundredMsFunc, 'name-thingy');
+
+      return instrumented().then(function() {
+
+        var stat = statsd.mockBuffer[0];
+        var name = stat.split(/:|\|/)[0];
+        var time = stat.split(/:|\|/)[1];
+
+        assert.equal(name, 'name-thingy');
+        assert.ok(parseFloat(time) >= 100);
+        assert.ok(parseFloat(time) < 200);
+      });
+    });
   });
 };
+
+
+function delay(n) {
+  return new Promise(function (resolve, reject) {
+    setTimeout(resolve, n);
+  });
+}