Add OpenCensus implementation

CHANGELOG

@@ -1,20 +1,39 @@
-## 0.3.0 / 2019-03-24
+# Changelog
 
-* [FEATURE] Add inflight requests metric per handler.
+## [Unreleased]
 
-## 0.2.0 / 2019-03-22
+### Breaking changes
+* The Recorder methods now receive a context argument.
 
-* [FEATURE] Add metrics of HTTP response size in bytes.
-* [ENHANCEMENT] Make the label names of Prometheus recorder configurable.
+### Added
+* OpenCensus recorder implementation.
 
-## 0.1.0 / 2019-03-18
+## [0.3.0] - 2019-03-24
 
-* [FEATURE] Add gorestful compatible middleware.
-* [FEATURE] Add httprouter compatible middleware.
-* [FEATURE] Add Negroni compatible middleware.
-* [FEATURE] Add option to group by status codes.
-* [FEATURE] Add predefined handler label.
-* [FEATURE] Add URL infered handler label.
-* [FEATURE] Add middleware.
-* [FEATURE] Add HTTP latency requests.
-* [FEATURE] Add Prometheus recorder.
+### Added
+* Inflight requests metric per handler.
+
+## [0.2.0] - 2019-03-22
+
+### Added
+* Metrics of HTTP response size in bytes.
+* Make the label names of Prometheus recorder configurable.
+
+## [0.1.0] - 2019-03-18
+
+### Added
+* Gorestful compatible middleware.
+* Httprouter compatible middleware.
+* Negroni compatible middleware.
+* Option to group by status codes.
+* Predefined handler label.
+* URL infered handler label.
+* Middleware.
+* HTTP latency requests.
+* Prometheus recorder.
+
+
+[unreleased]: https://github.com/slok/go-http-metrics/compare/v0.3.0...HEAD
+[0.3.0]: https://github.com/slok/go-http-metrics/compare/v0.2.0...v0.3.0
+[0.2.0]: https://github.com/slok/go-http-metrics/compare/v0.1.0...v0.2.0
+[0.1.0]: https://github.com/slok/go-http-metrics/releases/tag/v0.1.0

Readme.md

@@ -39,6 +39,7 @@ The metrics obtained with this middleware are the [most important ones][red] for
 go-http-metrics is easy to extend to different metric backends by implementing `metrics.Recorder` interface.
 
 - [Prometheus][prometheus-recorder]
+- [OpenCensus][opencensus-recorder]
 
 ## Framework compatibility middlewares
 
@@ -203,3 +204,4 @@ BenchmarkMiddlewareHandler/benchmark_with_predefined_handler_ID-4     	 1000000
 [httprouter-example]: examples/httprouter
 [gorestful-example]: examples/gorestful
 [prometheus-recorder]: metrics/prometheus
+[opencensus-recorder]: metrics/opencensus

examples/gin/main.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/gin-gonic/gin"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	prommiddleware "github.com/slok/go-prometheus-middleware"
+	promgin "github.com/slok/go-prometheus-middleware/gin"
+)
+
+const (
+	srvAddr     = ":8080"
+	metricsAddr = ":8081"
+)
+
+func main() {
+	// Create our middleware.
+	mdlw := prommiddleware.NewDefault()
+
+	// Create our gin instance.
+	r := gin.New()
+
+	// Add the middlewares to all gin routes.
+	r.Use(
+		promgin.Handler("", mdlw),
+		gin.Logger(),
+	)
+
+	// Add our handler
+	r.GET("/", func(c *gin.Context) {
+		c.String(http.StatusOK, "Hello world!")
+	})
+
+	// Serve our handler.
+	go func() {
+		log.Printf("server listening at %s", srvAddr)
+		if err := r.Run(srvAddr); err != nil {
+			log.Panicf("error while serving: %s", err)
+		}
+	}()
+
+	// Serve our metrics.
+	go func() {
+		log.Printf("metrics listening at %s", metricsAddr)
+		if err := http.ListenAndServe(metricsAddr, promhttp.Handler()); err != nil {
+			log.Panicf("error while serving metrics: %s", err)
+		}
+	}()
+
+	// Wait until some signal is captured.
+	sigC := make(chan os.Signal, 1)
+	signal.Notify(sigC, syscall.SIGTERM, syscall.SIGINT)
+	<-sigC
+}

examples/opencensus/main.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	ocmmetrics "github.com/slok/go-http-metrics/metrics/opencensus"
+	"github.com/slok/go-http-metrics/middleware"
+	ocprometheus "go.opencensus.io/exporter/prometheus"
+	"go.opencensus.io/stats/view"
+)
+
+const (
+	srvAddr     = ":8080"
+	metricsAddr = ":8081"
+)
+
+// This example will show how you could use opencensus with go-http-middleware
+// and serve the metrics in Prometheus format (through OpenCensus).
+func main() {
+	// Create OpenCensus with Prometheus.
+	ocexporter, err := ocprometheus.NewExporter(ocprometheus.Options{})
+	if err != nil {
+		log.Panicf("error creating OpenCensus exporter: %s", err)
+	}
+	view.RegisterExporter(ocexporter)
+	rec, err := ocmmetrics.NewRecorder(ocmmetrics.Config{})
+	if err != nil {
+		log.Panicf("error creating OpenCensus metrics recorder: %s", err)
+	}
+
+	// Create our middleware.
+	mdlw := middleware.New(middleware.Config{
+		Recorder: rec,
+	})
+
+	// Create our server.
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(200 * time.Millisecond)
+		w.WriteHeader(http.StatusOK)
+	})
+	mux.HandleFunc("/test1", func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusCreated) })
+	mux.HandleFunc("/test1/test2", func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusAccepted) })
+	mux.HandleFunc("/test1/test4", func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusNonAuthoritativeInfo) })
+	mux.HandleFunc("/test2", func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusNoContent) })
+	mux.HandleFunc("/test3", func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusResetContent) })
+
+	// Wrap our main handler, we pass empty handler ID so the middleware inferes
+	// the handler label from the URL.
+	h := mdlw.Handler("", mux)
+
+	// Serve our handler.
+	go func() {
+		log.Printf("server listening at %s", srvAddr)
+		if err := http.ListenAndServe(srvAddr, h); err != nil {
+			log.Panicf("error while serving: %s", err)
+		}
+	}()
+
+	// Serve our metrics.
+	go func() {
+		log.Printf("metrics listening at %s", metricsAddr)
+		if err := http.ListenAndServe(metricsAddr, ocexporter); err != nil {
+			log.Panicf("error while serving metrics: %s", err)
+		}
+	}()
+
+	// Wait until some signal is captured.
+	sigC := make(chan os.Signal, 1)
+	signal.Notify(sigC, syscall.SIGTERM, syscall.SIGINT)
+	<-sigC
+}

go.mod

@@ -2,8 +2,16 @@ module github.com/slok/go-http-metrics
 
 require (
 	github.com/emicklei/go-restful v2.9.0+incompatible
+	github.com/gin-gonic/gin v1.3.0
+	github.com/golang/mock v1.2.0 // indirect
+	github.com/json-iterator/go v1.1.6 // indirect
 	github.com/julienschmidt/httprouter v1.2.0
-	github.com/prometheus/client_golang v0.9.2
+	github.com/kr/pretty v0.1.0 // indirect
+	github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829
+	github.com/slok/go-prometheus-middleware v0.4.0
 	github.com/stretchr/testify v1.2.2
 	github.com/urfave/negroni v1.0.0
+	go.opencensus.io v0.19.2
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
+	gopkg.in/yaml.v2 v2.2.2 // indirect
 )