Increment stats for success/failure of wrapped async calls

libraries/metrics/test/unit/coffee/timeAsyncMethodTests.coffee

@@ -15,6 +15,7 @@ describe 'timeAsyncMethod', ->
 		@TimerConstructor = sinon.stub().returns(@Timer)
 		@metrics = {
 			Timer: @TimerConstructor
+			inc: sinon.stub()
 		}
 		@timeAsyncMethod = SandboxedModule.require modulePath, requires:
 			'./metrics': @metrics
@@ -35,11 +36,11 @@ describe 'timeAsyncMethod', ->
 			done()
 
 	it 'should wrap method without error', (done) ->
-		@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber'
+		@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
 		done()
 
 	it 'should transparently wrap method invocation in timer', (done) ->
-		@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber'
+		@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
 		@testObject.nextNumber 2, (err, result) =>
 			expect(err).to.not.exist
 			expect(result).to.equal 3
@@ -47,8 +48,17 @@ describe 'timeAsyncMethod', ->
 			expect(@Timer.done.callCount).to.equal 1
 			done()
 
+	it 'should increment success count', (done) ->
+		@metrics.inc = sinon.stub()
+		@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
+		@testObject.nextNumber 2, (err, result) =>
+			expect(@metrics.inc.callCount).to.equal 1
+			expect(@metrics.inc.calledWith('someContext.TestObject.nextNumber.success')).to.equal true
+			done()
+
 	describe 'when base method produces an error', ->
 		beforeEach ->
+			@metrics.inc = sinon.stub()
 			@testObject.nextNumber = (n, callback=(err, result)->) ->
 				setTimeout(
 					() ->
@@ -57,19 +67,26 @@ describe 'timeAsyncMethod', ->
 				)
 
 		it 'should propagate the error transparently', (done) ->
-			@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber'
+			@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
 			@testObject.nextNumber 2, (err, result) =>
 				expect(err).to.exist
 				expect(err).to.be.instanceof Error
 				expect(result).to.not.exist
 				done()
 
+		it 'should increment failure count', (done) ->
+			@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
+			@testObject.nextNumber 2, (err, result) =>
+				expect(@metrics.inc.callCount).to.equal 1
+				expect(@metrics.inc.calledWith('someContext.TestObject.nextNumber.failure')).to.equal true
+				done()
+
 	describe 'when a logger is supplied', ->
 		beforeEach ->
 			@logger = {log: sinon.stub()}
 
 		it 'should also call logger.log', (done) ->
-			@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber', @logger
+			@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject', @logger
 			@testObject.nextNumber 2, (err, result) =>
 				expect(err).to.not.exist
 				expect(result).to.equal 3
@@ -83,7 +100,7 @@ describe 'timeAsyncMethod', ->
 
 		it 'should raise an error', ->
 			badWrap = () =>
-				@timeAsyncMethod @testObject, 'DEFINITELY_NOT_A_REAL_METHOD', 'test.nextNumber'
+				@timeAsyncMethod @testObject, 'DEFINITELY_NOT_A_REAL_METHOD', 'someContext.TestObject'
 			expect(badWrap).to.throw(
 				/^.*expected object property 'DEFINITELY_NOT_A_REAL_METHOD' to be a function.*$/
 			)
@@ -94,13 +111,13 @@ describe 'timeAsyncMethod', ->
 			@testObject.nextNumber = @realMethod
 
 		it 'should not throw an error', ->
-			@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber'
+			@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
 			badCall = () =>
 				@testObject.nextNumber 2
 			expect(badCall).to.not.throw(Error)
 
 		it 'should call the underlying method', ->
-			@timeAsyncMethod @testObject, 'nextNumber', 'test.nextNumber'
+			@timeAsyncMethod @testObject, 'nextNumber', 'someContext.TestObject'
 			result = @testObject.nextNumber(12)
 			expect(@realMethod.callCount).to.equal 1
 			expect(@realMethod.calledWith(12)).to.equal true

libraries/metrics/timeAsyncMethod.coffee

@@ -21,6 +21,11 @@ module.exports = (obj, methodName, prefix, logger) ->
 
 		realMethod.call this, firstArgs..., (callbackArgs...) ->
 			elapsedTime = timer.done()
+			possibleError = callbackArgs[0]
+			if possibleError? && possibleError.message? && possibleError.stack?
+				metrics.inc "#{key}.failure"
+			else
+				metrics.inc "#{key}.success"
 			if logger?
 				loggableArgs = {}
 				try