Add an example of how to use Walk to add the Middleware to every hand…

…ler (#5)

Signed-off-by: Louis-Etienne Dorval <[email protected]>

README.md

@@ -1,2 +1,7 @@
 # go-gorilla
 OpenTracing instrumentation for Gorilla framework (github.com/gorilla)
+
+## Usage
+
+See usage examples in [gorilla/example_test.go](gorilla/example_test.go).
+

gorilla/example_test.go

@@ -2,29 +2,86 @@ package gorilla_test
 
 import (
 	"fmt"
+	"github.com/opentracing/opentracing-go"
+	"io"
 	"log"
 	"net/http"
 	"time"
 
 	"github.com/gorilla/mux"
 	"github.com/opentracing-contrib/go-gorilla/gorilla"
-	//"github.com/opentracing-contrib/go-stdlib/nethttp"
 	"github.com/uber/jaeger-client-go/config"
 )
 
-func ExampleTracingMiddleware() {
-	// http listen port
-	httpAddress := ":8800"
+// http listen port
+const httpAddress = ":8800"
+
+func ExampleGorilla_TracingSingleRoute() {
+	tracer, _, err := getTracer()
+
+	if err != nil {
+		log.Fatal("cannot initialize Jaeger Tracer", err)
+	}
 
-	//jaeger agent port
-	jaegerHostPort := ":6831"
 	myHandler := func(w http.ResponseWriter, r *http.Request) {
 		vars := mux.Vars(r)
 		idstr := vars["productId"]
 		//do something
 		data := "Hello, we get " + idstr
 		fmt.Fprintf(w, data)
 	}
+
+	r := mux.NewRouter()
+
+	pattern := "/v1/products/{productId}"
+
+	middleware := gorilla.Middleware(
+		tracer,
+		http.HandlerFunc(myHandler),
+	)
+
+	r.Handle(pattern, middleware)
+	log.Fatal(http.ListenAndServe(httpAddress, r))
+}
+
+func ExampleGorilla_TracingAllRoutes() {
+	tracer, _, err := getTracer()
+
+	if err != nil {
+		log.Fatal("cannot initialize Jaeger Tracer", err)
+	}
+
+	okHandler := func(w http.ResponseWriter, r *http.Request) {
+		// do something
+		data := "Hello"
+		fmt.Fprintf(w, data)
+	}
+
+	r := mux.NewRouter()
+	// Create multiples routes
+	r.HandleFunc("/v1/products", okHandler)
+	r.HandleFunc("/v1/products/{productId}", okHandler)
+	r.HandleFunc("/v2/products", okHandler)
+	r.HandleFunc("/v2/products/{productId}", okHandler)
+	r.HandleFunc("/v3/products", okHandler)
+	r.HandleFunc("/v3/products/{productId}", okHandler)
+	r.HandleFunc("/v4/products", okHandler)
+	r.HandleFunc("/v4/products/{productId}", okHandler)
+
+	// Add tracing to all routes
+	_ = r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
+		route.Handler(
+			gorilla.Middleware(tracer, route.GetHandler()))
+		return nil
+	})
+
+	log.Fatal(http.ListenAndServe(httpAddress, r))
+}
+
+func getTracer() (opentracing.Tracer, io.Closer, error) {
+	//jaeger agent port
+	jaegerHostPort := ":6831"
+
 	cfg := config.Configuration{
 		Sampler: &config.SamplerConfig{
 			Type:  "const",
@@ -36,23 +93,7 @@ func ExampleTracingMiddleware() {
 			LocalAgentHostPort:  jaegerHostPort,
 		},
 	}
-	tracer, _, err := cfg.New(
+	return cfg.New(
 		"ExampleTracingMiddleware", //service name
 	)
-
-	if err != nil {
-		log.Fatal("cannot initialize Jaeger Tracer", err)
-	}
-
-	r := mux.NewRouter()
-
-	pattern := "/v1/products/{productId}"
-
-	middleware := gorilla.Middleware(
-		tracer,
-		http.HandlerFunc(myHandler),
-	)
-
-	r.Handle(pattern, middleware)
-	log.Fatal(http.ListenAndServe(httpAddress, r))
 }