contrib/valyala/fasthttp.v1: add a fasthttp integration to ddtrace (#…

…2305)

Co-authored-by: Dario Castañé <dario.castane@datadoghq.com>
Co-authored-by: Rodrigo Argüello <rodrigo.arguello@datadoghq.com>

contrib/internal/fasthttptrace/fasthttpheaderscarrier.go

@@ -11,18 +11,18 @@ import (
 	"github.com/valyala/fasthttp"
 )
 
-// FastHTTPHeadersCarrier implements tracer.TextMapWriter and tracer.TextMapReader on top
+// HTTPHeadersCarrier implements tracer.TextMapWriter and tracer.TextMapReader on top
 // of fasthttp's RequestHeader object, allowing it to be used as a span context carrier for
 // distributed tracing.
-type FastHTTPHeadersCarrier struct {
+type HTTPHeadersCarrier struct {
 	ReqHeader *fasthttp.RequestHeader
 }
 
-var _ tracer.TextMapWriter = (*FastHTTPHeadersCarrier)(nil)
-var _ tracer.TextMapReader = (*FastHTTPHeadersCarrier)(nil)
+var _ tracer.TextMapWriter = (*HTTPHeadersCarrier)(nil)
+var _ tracer.TextMapReader = (*HTTPHeadersCarrier)(nil)
 
 // ForeachKey iterates over fasthttp request header keys and values
-func (f *FastHTTPHeadersCarrier) ForeachKey(handler func(key, val string) error) error {
+func (f *HTTPHeadersCarrier) ForeachKey(handler func(key, val string) error) error {
 	keys := f.ReqHeader.PeekKeys()
 	for _, key := range keys {
 		sKey := string(key)
@@ -36,6 +36,6 @@ func (f *FastHTTPHeadersCarrier) ForeachKey(handler func(key, val string) error)
 
 // Set adds the given value to request header for key. Key will be lowercased to match
 // the metadata implementation.
-func (f *FastHTTPHeadersCarrier) Set(key, val string) {
+func (f *HTTPHeadersCarrier) Set(key, val string) {
 	f.ReqHeader.Set(key, val)
 }

contrib/internal/fasthttptrace/fasthttpheaderscarrier_test.go

@@ -17,9 +17,9 @@ import (
 	"github.com/valyala/fasthttp"
 )
 
-func TestFastHTTPHeadersCarrierSet(t *testing.T) {
+func TestHTTPHeadersCarrierSet(t *testing.T) {
 	assert := assert.New(t)
-	fcc := &FastHTTPHeadersCarrier{
+	fcc := &HTTPHeadersCarrier{
 		ReqHeader: new(fasthttp.RequestHeader),
 	}
 	t.Run("key-val", func(t *testing.T) {
@@ -55,7 +55,7 @@ func TestFastHTTPHeadersCarrierSet(t *testing.T) {
 	})
 }
 
-func TestFastHTTPHeadersCarrierForeachKey(t *testing.T) {
+func TestHTTPHeadersCarrierForeachKey(t *testing.T) {
 	assert := assert.New(t)
 	h := new(fasthttp.RequestHeader)
 	headers := map[string][]string{
@@ -68,7 +68,7 @@ func TestFastHTTPHeadersCarrierForeachKey(t *testing.T) {
 			h.Add(k, v)
 		}
 	}
-	fcc := &FastHTTPHeadersCarrier{
+	fcc := &HTTPHeadersCarrier{
 		ReqHeader: h,
 	}
 	err := fcc.ForeachKey(func(k, v string) error {
@@ -84,7 +84,7 @@ func TestInjectExtract(t *testing.T) {
 	mt := mocktracer.Start()
 	defer mt.Stop()
 	pspan, _ := tracer.StartSpanFromContext(context.Background(), "test")
-	fcc := &FastHTTPHeadersCarrier{
+	fcc := &HTTPHeadersCarrier{
 		ReqHeader: &fasthttp.RequestHeader{},
 	}
 	err := tracer.Inject(pspan.Context(), fcc)

contrib/valyala/fasthttp.v1/example_test.go

@@ -0,0 +1,37 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2016 Datadog, Inc.
+
+package fasthttp_test
+
+import (
+	"fmt"
+
+	fasthttptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/valyala/fasthttp.v1"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+
+	"github.com/valyala/fasthttp"
+)
+
+func fastHTTPHandler(ctx *fasthttp.RequestCtx) {
+	fmt.Fprintf(ctx, "Hello World!")
+}
+
+func Example() {
+	// Start the tracer
+	tracer.Start()
+	defer tracer.Stop()
+
+	// Start fasthttp server
+	fasthttp.ListenAndServe(":8081", fasthttptrace.WrapHandler(fastHTTPHandler))
+}
+
+func Example_withServiceName() {
+	// Start the tracer
+	tracer.Start()
+	defer tracer.Stop()
+
+	// Start fasthttp server
+	fasthttp.ListenAndServe(":8081", fasthttptrace.WrapHandler(fastHTTPHandler, fasthttptrace.WithServiceName("fasthttp-server")))
+}

contrib/valyala/fasthttp.v1/fasthttp.go

@@ -0,0 +1,77 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2016 Datadog, Inc.
+
+// Package fasthttp provides functions to trace the valyala/fasthttp package (https://github.com/valyala/fasthttp)
+package fasthttp // import "gopkg.in/DataDog/dd-trace-go.v1/contrib/valyala/fasthttp.v1"
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/valyala/fasthttp"
+	"gopkg.in/DataDog/dd-trace-go.v1/contrib/internal/fasthttptrace"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+	"gopkg.in/DataDog/dd-trace-go.v1/internal/log"
+	"gopkg.in/DataDog/dd-trace-go.v1/internal/telemetry"
+)
+
+const componentName = "valyala/fasthttp.v1"
+
+func init() {
+	telemetry.LoadIntegration(componentName)
+	tracer.MarkIntegrationImported(componentName)
+}
+
+// WrapHandler wraps a fasthttp.RequestHandler with tracing middleware
+func WrapHandler(h fasthttp.RequestHandler, opts ...Option) fasthttp.RequestHandler {
+	cfg := newConfig()
+	for _, fn := range opts {
+		fn(cfg)
+	}
+	log.Debug("contrib/valyala/fasthttp.v1: Configuring Middleware: cfg: %#v", cfg)
+	spanOpts := []tracer.StartSpanOption{
+		tracer.ServiceName(cfg.serviceName),
+	}
+	return func(fctx *fasthttp.RequestCtx) {
+		if cfg.ignoreRequest(fctx) {
+			h(fctx)
+			return
+		}
+		spanOpts = append(spanOpts, defaultSpanOptions(fctx)...)
+		fcc := &fasthttptrace.HTTPHeadersCarrier{
+			ReqHeader: &fctx.Request.Header,
+		}
+		if sctx, err := tracer.Extract(fcc); err == nil {
+			spanOpts = append(spanOpts, tracer.ChildOf(sctx))
+		}
+		span := fasthttptrace.StartSpanFromContext(fctx, "http.request", spanOpts...)
+		defer span.Finish()
+		h(fctx)
+		span.SetTag(ext.ResourceName, cfg.resourceNamer(fctx))
+		status := fctx.Response.StatusCode()
+		if cfg.isStatusError(status) {
+			span.SetTag(ext.Error, fmt.Errorf("%d: %s", status, string(fctx.Response.Body())))
+		}
+		span.SetTag(ext.HTTPCode, strconv.Itoa(status))
+	}
+}
+
+func defaultSpanOptions(fctx *fasthttp.RequestCtx) []tracer.StartSpanOption {
+	opts := []ddtrace.StartSpanOption{
+		tracer.Tag(ext.Component, componentName),
+		tracer.Tag(ext.SpanKind, ext.SpanKindServer),
+		tracer.SpanType(ext.SpanTypeWeb),
+		tracer.Tag(ext.HTTPMethod, string(fctx.Method())),
+		tracer.Tag(ext.HTTPURL, string(fctx.URI().FullURI())),
+		tracer.Tag(ext.HTTPUserAgent, string(fctx.UserAgent())),
+		tracer.Measured(),
+	}
+	if host := string(fctx.Host()); len(host) > 0 {
+		opts = append(opts, tracer.Tag("http.host", host))
+	}
+	return opts
+}