Merge pull request #6 from shwoodard/allow-instrumentation

allow instrumenting serialization and deserialization--event firehose

examples/app.go

@@ -16,9 +16,11 @@ import (
 )
 
 func createBlog(w http.ResponseWriter, r *http.Request) {
+	jsonapiRuntime := jsonapi.NewRuntime().Instrument("blogs.create")
+
 	blog := new(Blog)
 
-	if err := jsonapi.UnmarshalPayload(r.Body, blog); err != nil {
+	if err := jsonapiRuntime.UnmarshalPayload(r.Body, blog); err != nil {
 		http.Error(w, err.Error(), 500)
 		return
 	}
@@ -28,12 +30,13 @@ func createBlog(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(201)
 	w.Header().Set("Content-Type", "application/vnd.api+json")
 
-	if err := jsonapi.MarshalOnePayload(w, blog); err != nil {
+	if err := jsonapiRuntime.MarshalOnePayload(w, blog); err != nil {
 		http.Error(w, err.Error(), 500)
 	}
 }
 
 func listBlogs(w http.ResponseWriter, r *http.Request) {
+	jsonapiRuntime := jsonapi.NewRuntime().Instrument("blogs.list")
 	// ...fetch your blogs, filter, offset, limit, etc...
 
 	// but, for now
@@ -41,7 +44,7 @@ func listBlogs(w http.ResponseWriter, r *http.Request) {
 
 	w.WriteHeader(200)
 	w.Header().Set("Content-Type", "application/vnd.api+json")
-	if err := jsonapi.MarshalManyPayload(w, blogs); err != nil {
+	if err := jsonapiRuntime.MarshalManyPayload(w, blogs); err != nil {
 		http.Error(w, err.Error(), 500)
 	}
 }
@@ -54,18 +57,42 @@ func showBlog(w http.ResponseWriter, r *http.Request) {
 	intId, err := strconv.Atoi(id)
 	if err != nil {
 		http.Error(w, err.Error(), 500)
+		return
 	}
+
+	jsonapiRuntime := jsonapi.NewRuntime().Instrument("blogs.show")
+
 	// but, for now
 	blog := testBlogForCreate(intId)
 	w.WriteHeader(200)
 
 	w.Header().Set("Content-Type", "application/vnd.api+json")
-	if err := jsonapi.MarshalOnePayload(w, blog); err != nil {
+	if err := jsonapiRuntime.MarshalOnePayload(w, blog); err != nil {
 		http.Error(w, err.Error(), 500)
 	}
 }
 
 func main() {
+	jsonapi.Instrumentation = func(r *jsonapi.Runtime, eventType jsonapi.Event, callGUID string, dur time.Duration) {
+		metricPrefix := r.Value("instrument").(string)
+
+		if eventType == jsonapi.UnmarshalStart {
+			fmt.Printf("%s: id, %s, started at %v\n", metricPrefix+".jsonapi_unmarshal_time", callGUID, time.Now())
+		}
+
+		if eventType == jsonapi.UnmarshalStop {
+			fmt.Printf("%s: id, %s, stopped at, %v , and took %v to unmarshal paylaod\n", metricPrefix+".jsonapi_unmarshal_time", callGUID, time.Now(), dur)
+		}
+
+		if eventType == jsonapi.MarshalStart {
+			fmt.Printf("%s: id, %s, started at %v\n", metricPrefix+".jsonapi_marshal_time", callGUID, time.Now())
+		}
+
+		if eventType == jsonapi.MarshalStop {
+			fmt.Printf("%s: id, %s, stopped at, %v , and took %v to marshal paylaod\n", metricPrefix+".jsonapi_marshal_time", callGUID, time.Now(), dur)
+		}
+	}
+
 	http.HandleFunc("/blogs", func(w http.ResponseWriter, r *http.Request) {
 		if !regexp.MustCompile(`application/vnd\.api\+json`).Match([]byte(r.Header.Get("Accept"))) {
 			http.Error(w, "Unsupported Media Type", 415)
@@ -157,7 +184,9 @@ func exerciseHandler() {
 
 	w := httptest.NewRecorder()
 
+	fmt.Println("============ start list ===========\n")
 	http.DefaultServeMux.ServeHTTP(w, req)
+	fmt.Println("============ stop list ===========\n")
 
 	jsonReply, _ := ioutil.ReadAll(w.Body)
 
@@ -172,7 +201,9 @@ func exerciseHandler() {
 
 	w = httptest.NewRecorder()
 
+	fmt.Println("============ start show ===========\n")
 	http.DefaultServeMux.ServeHTTP(w, req)
+	fmt.Println("============ stop show ===========\n")
 
 	jsonReply, _ = ioutil.ReadAll(w.Body)
 
@@ -191,7 +222,9 @@ func exerciseHandler() {
 
 	w = httptest.NewRecorder()
 
+	fmt.Println("============ start create ===========\n")
 	http.DefaultServeMux.ServeHTTP(w, req)
+	fmt.Println("============ stop create ===========\n")
 
 	buf := bytes.NewBuffer(nil)
 	io.Copy(buf, w.Body)

runtime.go

@@ -0,0 +1,106 @@
+package jsonapi
+
+import (
+	"crypto/rand"
+	"fmt"
+	"io"
+	"time"
+)
+
+type Event int
+
+const (
+	UnmarshalStart Event = iota
+	UnmarshalStop
+	MarshalStart
+	MarshalStop
+)
+
+type Runtime struct {
+	ctx map[string]interface{}
+}
+
+type Events func(*Runtime, Event, string, time.Duration)
+
+var Instrumentation Events
+
+func NewRuntime() *Runtime { return &Runtime{make(map[string]interface{})} }
+
+func (r *Runtime) WithValue(key string, value interface{}) *Runtime {
+	r.ctx[key] = value
+
+	return r
+}
+
+func (r *Runtime) Value(key string) interface{} {
+	return r.ctx[key]
+}
+
+func (r *Runtime) Instrument(key string) *Runtime {
+	return r.WithValue("instrument", key)
+}
+
+func (r *Runtime) shouldInstrument() bool {
+	return Instrumentation != nil
+}
+
+func (r *Runtime) UnmarshalPayload(reader io.Reader, model interface{}) error {
+	return r.instrumentCall(UnmarshalStart, UnmarshalStop, func() error {
+		return UnmarshalPayload(reader, model)
+	})
+}
+
+func (r *Runtime) MarshalOnePayload(w io.Writer, model interface{}) error {
+	return r.instrumentCall(MarshalStart, MarshalStop, func() error {
+		return MarshalOnePayload(w, model)
+	})
+}
+
+func (r *Runtime) MarshalManyPayload(w io.Writer, models []interface{}) error {
+	return r.instrumentCall(MarshalStart, MarshalStop, func() error {
+		return MarshalManyPayload(w, models)
+	})
+}
+
+func (r *Runtime) MarshalOnePayloadEmbedded(w io.Writer, model interface{}) error {
+	return r.instrumentCall(MarshalStart, MarshalStop, func() error {
+		return MarshalOnePayloadEmbedded(w, model)
+	})
+}
+
+func (r *Runtime) instrumentCall(start Event, stop Event, c func() error) error {
+	if !r.shouldInstrument() {
+		return c()
+	}
+
+	instrumentationGUID, err := newUUID()
+	if err != nil {
+		return err
+	}
+
+	begin := time.Now()
+	Instrumentation(r, start, instrumentationGUID, time.Duration(0))
+
+	if err := c(); err != nil {
+		return err
+	}
+
+	diff := time.Duration(time.Now().UnixNano() - begin.UnixNano())
+	Instrumentation(r, stop, instrumentationGUID, diff)
+
+	return nil
+}
+
+// citation: http://play.golang.org/p/4FkNSiUDMg
+func newUUID() (string, error) {
+	uuid := make([]byte, 16)
+	n, err := io.ReadFull(rand.Reader, uuid)
+	if n != len(uuid) || err != nil {
+		return "", err
+	}
+	// variant bits; see section 4.1.1
+	uuid[8] = uuid[8]&^0xc0 | 0x80
+	// version 4 (pseudo-random); see section 4.1.3
+	uuid[6] = uuid[6]&^0xf0 | 0x40
+	return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:]), nil
+}