added metric to see how often caduceus is modifying the wrp

CHANGELOG.md

@@ -8,13 +8,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - The next release needs to be v0.3.0 because #217 & #219.
 
 ## [Unreleased]
+- added metric for counting when caduceus re-encodes the wrp [#216](https://github.com/xmidt-org/caduceus/pull/216)
 - Made outgoing hostname validation configurable [#217](https://github.com/xmidt-org/caduceus/pull/217)
   - **Note:** To be backwards compatable, the configuration value of `allowInsecureTLS: true` will need to be defined, otherwise hostname validation is enabled by default.
 - removed contentTypeCounter [#218](https://github.com/xmidt-org/caduceus/pull/218)
 - added configuration for which http codes Caduceus should retry on [#219](https://github.com/xmidt-org/caduceus/pull/219)
   - **Note:** This configuration change causes the existing retry logic to change.
 
 
+
 ## [v0.2.8]
 ### Changed
 - cleaned up shutdown logic for outbound sender [#205](https://github.com/xmidt-org/caduceus/pull/205)

http.go

@@ -37,6 +37,7 @@ type ServerHandler struct {
 	emptyRequests            metrics.Counter
 	invalidCount             metrics.Counter
 	incomingQueueDepthMetric metrics.Gauge
+	modifiedWRPCount         metrics.Counter
 	incomingQueueDepth       int64
 	maxOutstanding           int64
 }
@@ -91,26 +92,37 @@ func (sh *ServerHandler) ServeHTTP(response http.ResponseWriter, request *http.R
 		return
 	}
 
-	sh.caduceusHandler.HandleRequest(0, fixWrp(msg))
+	sh.caduceusHandler.HandleRequest(0, sh.fixWrp(msg))
 
 	// return a 202
 	response.WriteHeader(http.StatusAccepted)
 	response.Write([]byte("Request placed on to queue.\n"))
 	debugLog.Log(messageKey, "Request placed on to queue.")
 }
 
-func fixWrp(msg *wrp.Message) *wrp.Message {
+func (sh *ServerHandler) fixWrp(msg *wrp.Message) *wrp.Message {
 	// "Fix" the WRP if needed.
+	var reason string
 
 	// Default to "application/json" if there is no content type, otherwise
 	// use the one the source specified.
 	if "" == msg.ContentType {
 		msg.ContentType = "application/json"
+		reason = emptyContentTypeReason
 	}
 
 	// Ensure there is a transaction id even if we make one up
 	if "" == msg.TransactionUUID {
 		msg.TransactionUUID = uuid.NewV4().String()
+		if reason == "" {
+			reason = emptyUUIDReason
+		} else {
+			reason = bothEmptyReason
+		}
+	}
+
+	if reason != "" {
+		sh.modifiedWRPCount.With("reason", reason).Add(1.0)
 	}
 
 	return msg

http_test.go

@@ -118,12 +118,22 @@ func TestServerHandlerFixWrp(t *testing.T) {
 	fakeQueueDepth := new(mockGauge)
 	fakeQueueDepth.On("Add", mock.AnythingOfType("float64")).Return().Times(2)
 
+	fakeIncomingContentTypeCount := new(mockCounter)
+	fakeIncomingContentTypeCount.On("With", []string{"content_type", "application/msgpack"}).Return(fakeIncomingContentTypeCount)
+	fakeIncomingContentTypeCount.On("With", []string{"content_type", ""}).Return(fakeIncomingContentTypeCount)
+	fakeIncomingContentTypeCount.On("Add", 1.0).Return()
+
+	fakeModifiedWRPCount := new(mockCounter)
+	fakeModifiedWRPCount.On("With", []string{"reason", bothEmptyReason}).Return(fakeIncomingContentTypeCount).Once()
+	fakeModifiedWRPCount.On("Add", 1.0).Return().Once()
+
 	serverWrapper := &ServerHandler{
 		Logger:                   logger,
 		caduceusHandler:          fakeHandler,
 		errorRequests:            fakeErrorRequests,
 		emptyRequests:            fakeEmptyRequests,
 		invalidCount:             fakeInvalidCount,
+		modifiedWRPCount:         fakeModifiedWRPCount,
 		incomingQueueDepthMetric: fakeQueueDepth,
 		maxOutstanding:           1,
 	}

main.go

@@ -135,6 +135,7 @@ func caduceus(arguments []string) int {
 		emptyRequests:            metricsRegistry.NewCounter(EmptyRequestBodyCounter),
 		invalidCount:             metricsRegistry.NewCounter(DropsDueToInvalidPayload),
 		incomingQueueDepthMetric: metricsRegistry.NewGauge(IncomingQueueDepth),
+		modifiedWRPCount:         metricsRegistry.NewCounter(ModifiedWRPCounter),
 		maxOutstanding:           0,
 	}
 

metrics.go

@@ -7,6 +7,7 @@ import (
 const (
 	ErrorRequestBodyCounter         = "error_request_body_count"
 	EmptyRequestBodyCounter         = "empty_request_body_count"
+	ModifiedWRPCounter              = "modified_wrp_count"
 	DeliveryCounter                 = "delivery_count"
 	DeliveryRetryCounter            = "delivery_retry_count"
 	DeliveryRetryMaxGauge           = "delivery_retry_max"
@@ -24,6 +25,12 @@ const (
 	ConsumerMaxDeliveryWorkersGauge = "consumer_delivery_workers_max"
 )
 
+const (
+	emptyContentTypeReason = "empty_content_type"
+	emptyUUIDReason        = "empty_uuid"
+	bothEmptyReason        = "empty_uuid_and_content_type"
+)
+
 func Metrics() []xmetrics.Metric {
 	return []xmetrics.Metric{
 		{
@@ -46,6 +53,18 @@ func Metrics() []xmetrics.Metric {
 			Help: "Dropped messages due to invalid payloads.",
 			Type: "counter",
 		},
+		{
+			Name:       ModifiedWRPCounter,
+			Help:       "Number of times a WRP was modified by Caduceus",
+			Type:       "counter",
+			LabelNames: []string{"reason"},
+		},
+		{
+			Name:       IncomingContentTypeCounter,
+			Help:       "Count of the content type processed.",
+			Type:       "counter",
+			LabelNames: []string{"content_type"},
+		},
 		{
 			Name:       DeliveryRetryCounter,
 			Help:       "Number of delivery retries made",