Merge pull request #53 from trentmwillis/metrics

Properly handle errors when thrown inside measured function

index.js

@@ -44,16 +44,26 @@ function defineFunction(obj, name, fn) {
 
     metrics.start();
 
-    var result = fn.apply(this, arguments);
+    var result;
+    var didError = true;
+
+    try {
+      result = fn.apply(this, arguments);
+      didError = false;
+    } finally {
+      if (didError) {
+        metrics.stop();
+      }
+    }
 
     if (typeof result.finally === 'function') {
       return result.finally(function() {
         metrics.stop();
       });
-    } else {
-      metrics.stop();
-      return result;
     }
+
+    metrics.stop();
+    return result;
   };
 }
 

test.js

@@ -9,6 +9,7 @@ var expect = chai.expect;
 var RSVP = require('rsvp');
 var Mode = require('stat-mode');
 var crypto = require('crypto');
+var heimdall = require('heimdalljs');
 
 describe('cache', function() {
   var cache;
@@ -114,6 +115,11 @@ describe('cache', function() {
       })
     ]);
   });
+
+  it('properly stops metrics when an error occurs', function() {
+    expect(function() { cache.pathFor(); }).to.throw();
+    expect(heimdall.statsFor('async-disk-cache').pathFor.startTime).to.be.undefined;
+  });
 });
 
 var zlib = require('zlib');