Merge pull request #32 from foodora/newrelic_transaction_manually

NewRelic add method to start transaction manually and send error messages to newrelic

ranger_metrics/newrelic.go

@@ -1,27 +1,29 @@
 package ranger_metrics
 
 import (
-	newrelic "github.com/newrelic/go-agent"
+	"errors"
 	"net/http"
+
 	"github.com/foodora/go-ranger/ranger_logger"
+	newrelic "github.com/newrelic/go-agent"
 )
 
 type NewRelic struct {
 	Application newrelic.Application
+	logger      ranger_logger.LoggerInterface
 }
 
 func NewNewRelic(appName string, license string, logger ranger_logger.LoggerInterface) *NewRelic {
-	app, err := newrelic.NewApplication(newrelic.NewConfig(
-		appName,
-		license),
-	)
+	config := newrelic.NewConfig(appName, license)
 
+	app, err := newrelic.NewApplication(config)
 	if err != nil {
 		logger.Panic("NewRelic error", ranger_logger.LoggerData{"error": err.Error()})
 	}
 
 	return &NewRelic{
 		Application: app,
+		logger:      logger,
 	}
 }
 
@@ -30,8 +32,37 @@ func (newRelic *NewRelic) Middleware(next http.Handler) http.Handler {
 		txn := newRelic.Application.StartTransaction(r.URL.Path, w, r)
 		defer txn.End()
 
-		next.ServeHTTP(w, r)
+		next.ServeHTTP(txn, r)
 	}
 
 	return http.HandlerFunc(fn)
 }
+
+// StartTransaction start a transaction manually
+// * Call the returned function to end the transaction
+func (newRelic *NewRelic) StartTransaction(w http.ResponseWriter, r *http.Request) func() {
+	txn := newRelic.Application.StartTransaction(r.URL.Path, w, r)
+
+	return func() {
+		txn.End()
+	}
+}
+
+// NoticeError send content of err to newrelic using trasaction
+// that middleware has started
+func (newRelic *NewRelic) NoticeError(w http.ResponseWriter, err error) {
+	if txn, ok := w.(newrelic.Transaction); ok {
+		txnErr := txn.NoticeError(err)
+		if txnErr != nil {
+			newRelic.logger.Error("Cannot send error to NewRelic", ranger_logger.LoggerData{
+				"error": err.Error(),
+			})
+		}
+
+		return
+	}
+
+	newRelic.logger.Error("Cannot send error to NewRelic", ranger_logger.LoggerData{
+		"error": errors.New("Transaction wasn't started by NewRelic Middleware"),
+	})
+}

ranger_metrics/newrelic_test.go

@@ -1,7 +1,46 @@
 package ranger_metrics
 
-import "testing"
+import (
+	"errors"
+	"net/http"
+	"testing"
+
+	"github.com/foodora/go-ranger/ranger_logger"
+)
 
 func TestInitNewRelic(t *testing.T) {
 	//t.Error("@todo TestInitNewRelic")
 }
+
+func ExampleStartTransactionManually() {
+	var logger ranger_logger.LoggerInterface
+
+	newRelic := NewNewRelic("appName", "license", logger)
+
+	// Start and end manually
+	closeTxn := newRelic.StartTransaction(nil, nil)
+	// your code here
+	closeTxn()
+
+	// Start and end with defer
+	closeTxn = newRelic.StartTransaction(nil, nil)
+	defer closeTxn()
+	// your code here
+
+	// Start and end with defer in the same line
+	defer newRelic.StartTransaction(nil, nil)()
+	// your code here
+}
+
+func ExampleNoticeError() {
+	var logger ranger_logger.LoggerInterface
+
+	newRelic := NewNewRelic("appName", "license", logger)
+
+	// Ensure that your handler is called by NewRelic.Middleware
+	handler := newRelic.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		newRelic.NoticeError(w, errors.New("Application failed!"))
+	}))
+
+	http.Handle("/foo", handler)
+}