WIP: implement DD_TRACE_INTEGRATION_TAGS + contrib/net/http support

contrib/net/http/internal/config/config.go

@@ -23,14 +23,15 @@ const (
 )
 
 type Config struct {
-	SpanOpts      []ddtrace.StartSpanOption
-	FinishOpts    []ddtrace.FinishOption
-	IgnoreRequest func(*http.Request) bool
-	ResourceNamer func(*http.Request) string
-	IsStatusError func(int) bool
-	HeaderTags    *internal.LockMap
-	ServiceName   string
-	AnalyticsRate float64
+	SpanOpts        []ddtrace.StartSpanOption
+	FinishOpts      []ddtrace.FinishOption
+	IgnoreRequest   func(*http.Request) bool
+	ResourceNamer   func(*http.Request) string
+	IsStatusError   func(int) bool
+	HeaderTags      *internal.LockMap
+	ServiceName     string
+	AnalyticsRate   float64
+	IntegrationTags *internal.IntegrationTags
 }
 
 // Option represents an option that can be passed to NewServeMux or WrapHandler.
@@ -52,6 +53,7 @@ func Default() *Config {
 	}
 	cfg.IgnoreRequest = func(_ *http.Request) bool { return false }
 	cfg.ResourceNamer = func(_ *http.Request) string { return "" }
+	cfg.IntegrationTags = globalconfig.IntegrationTags()
 
 	return cfg
 }

contrib/net/http/internal/wrap/mux.go

@@ -6,6 +6,7 @@
 package wrap
 
 import (
+	"net"
 	"net/http"
 
 	"gopkg.in/DataDog/dd-trace-go.v1/contrib/internal/httptrace"
@@ -55,6 +56,11 @@ func (mux *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	so := make([]ddtrace.StartSpanOption, len(mux.cfg.SpanOpts), len(mux.cfg.SpanOpts)+1)
 	copy(so, mux.cfg.SpanOpts)
 	so = append(so, httptrace.HeaderTagsFromRequest(r, mux.cfg.HeaderTags))
+
+	for k, v := range serverIntegrationTags(mux.cfg, r) {
+		so = append(so, tracer.Tag(k, v))
+	}
+
 	TraceAndServe(mux.ServeMux, w, r, &httptrace.ServeConfig{
 		Service:       mux.cfg.ServiceName,
 		Resource:      resource,
@@ -64,3 +70,29 @@ func (mux *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		RouteParams:   patternValues(pattern, r),
 	})
 }
+
+func serverIntegrationTags(cfg *config.Config, req *http.Request) map[string]string {
+	host, port := serverHostPort(req)
+
+	q := map[string]string{
+		"span.kind":           ext.SpanKindServer,
+		"server.address":      host,
+		"server.port":         port,
+		"url.path":            req.URL.Path,
+		"http.request.method": req.Method,
+	}
+	return cfg.IntegrationTags.Get(config.ComponentName, q)
+}
+
+func serverHostPort(req *http.Request) (string, string) {
+	ctxLocalAddr := req.Context().Value(http.LocalAddrContextKey)
+	if ctxLocalAddr == nil {
+		return "", ""
+	}
+	addr, ok := ctxLocalAddr.(net.Addr)
+	if !ok {
+		return "", ""
+	}
+	host, port, _ := net.SplitHostPort(addr.String())
+	return host, port
+}

contrib/net/http/option.go

@@ -114,18 +114,19 @@ type RoundTripperBeforeFunc func(*http.Request, ddtrace.Span)
 // RoundTrip is made. It is possible for the http Response to be nil.
 type RoundTripperAfterFunc func(*http.Response, ddtrace.Span)
 type roundTripperConfig struct {
-	before        RoundTripperBeforeFunc
-	after         RoundTripperAfterFunc
-	analyticsRate float64
-	serviceName   string
-	resourceNamer func(req *http.Request) string
-	spanNamer     func(req *http.Request) string
-	ignoreRequest func(*http.Request) bool
-	spanOpts      []ddtrace.StartSpanOption
-	propagation   bool
-	errCheck      func(err error) bool
-	queryString   bool // reports whether the query string is included in the URL tag for http client spans
-	isStatusError func(statusCode int) bool
+	before          RoundTripperBeforeFunc
+	after           RoundTripperAfterFunc
+	analyticsRate   float64
+	serviceName     string
+	resourceNamer   func(req *http.Request) string
+	spanNamer       func(req *http.Request) string
+	ignoreRequest   func(*http.Request) bool
+	spanOpts        []ddtrace.StartSpanOption
+	propagation     bool
+	errCheck        func(err error) bool
+	queryString     bool // reports whether the query string is included in the URL tag for http client spans
+	isStatusError   func(statusCode int) bool
+	integrationTags *internal.IntegrationTags
 }
 
 func newRoundTripperConfig() *roundTripperConfig {
@@ -138,14 +139,15 @@ func newRoundTripperConfig() *roundTripperConfig {
 	}
 
 	c := &roundTripperConfig{
-		serviceName:   namingschema.ServiceNameOverrideV0("", ""),
-		analyticsRate: globalconfig.AnalyticsRate(),
-		resourceNamer: defaultResourceNamer,
-		propagation:   true,
-		spanNamer:     defaultSpanNamer,
-		ignoreRequest: func(_ *http.Request) bool { return false },
-		queryString:   internal.BoolEnv(envClientQueryStringEnabled, true),
-		isStatusError: isClientError,
+		serviceName:     namingschema.ServiceNameOverrideV0("", ""),
+		analyticsRate:   globalconfig.AnalyticsRate(),
+		resourceNamer:   defaultResourceNamer,
+		propagation:     true,
+		spanNamer:       defaultSpanNamer,
+		ignoreRequest:   func(_ *http.Request) bool { return false },
+		queryString:     internal.BoolEnv(envClientQueryStringEnabled, true),
+		isStatusError:   isClientError,
+		integrationTags: globalconfig.IntegrationTags(),
 	}
 	v := os.Getenv(envClientErrorStatuses)
 	if fn := httptrace.GetErrorCodesFromInput(v); fn != nil {

contrib/net/http/roundtripper.go

@@ -57,6 +57,11 @@ func (rt *roundTripper) RoundTrip(req *http.Request) (res *http.Response, err er
 	if len(rt.cfg.spanOpts) > 0 {
 		opts = append(opts, rt.cfg.spanOpts...)
 	}
+	if tags := rt.clientIntegrationTags(req); tags != nil {
+		for k, v := range tags {
+			opts = append(opts, tracer.Tag(k, v))
+		}
+	}
 	span, ctx := tracer.StartSpanFromContext(req.Context(), spanName, opts...)
 	defer func() {
 		if rt.cfg.after != nil {
@@ -108,6 +113,17 @@ func (rt *roundTripper) Unwrap() http.RoundTripper {
 	return rt.base
 }
 
+func (rt *roundTripper) clientIntegrationTags(req *http.Request) map[string]string {
+	q := map[string]string{
+		"span.kind":           "client",
+		"server.address":      req.URL.Hostname(),
+		"server.port":         req.URL.Port(),
+		"url.path":            req.URL.Path,
+		"http.request.method": req.Method,
+	}
+	return rt.cfg.integrationTags.Get(config.ComponentName, q)
+}
+
 // WrapRoundTripper returns a new RoundTripper which traces all requests sent
 // over the transport.
 func WrapRoundTripper(rt http.RoundTripper, opts ...RoundTripperOption) http.RoundTripper {

contrib/net/http/roundtripper_test.go

@@ -28,6 +28,7 @@ import (
 	"gopkg.in/DataDog/dd-trace-go.v1/internal/appsec"
 	"gopkg.in/DataDog/dd-trace-go.v1/internal/appsec/emitter/waf/addresses"
 	"gopkg.in/DataDog/dd-trace-go.v1/internal/globalconfig"
+	internallog "gopkg.in/DataDog/dd-trace-go.v1/internal/log"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -830,3 +831,95 @@ func TestAppsec(t *testing.T) {
 		})
 	}
 }
+
+func TestIntegrationTags(t *testing.T) {
+	srv1 := httptest.NewServer(nil)
+	defer srv1.Close()
+	srv1URL, err := url.Parse(srv1.URL)
+	require.NoError(t, err)
+
+	srv2 := httptest.NewServer(nil)
+	defer srv2.Close()
+	srv2URL, err := url.Parse(srv2.URL)
+	require.NoError(t, err)
+
+	integrationTagsEnv := `[
+	{
+		"component": "net/http",
+		"query": [
+			{"span.kind": "server", "server.port": "%s"},
+			{"span.kind": "client", "server.port": "%s", "http.request.method": "GET"}
+		],
+		"tags": {
+			"tag1": "val1"
+		}
+	},
+	{
+		"component": "net/http",
+		"query": [
+			{"span.kind": "server", "server.port": "%s"}
+		],
+		"tags": {
+			"tag2": "val2"
+		}
+	}
+]`
+	t.Setenv("DD_TRACE_INTEGRATION_TAGS", fmt.Sprintf(integrationTagsEnv, srv1URL.Port(), srv2URL.Port(), srv2URL.Port()))
+
+	// force start-stop the real tracer to load the config
+	tracer.Start(tracer.WithLogger(internallog.DiscardLogger{}))
+	tracer.Stop()
+
+	mt := mocktracer.Start()
+	defer mt.Stop()
+
+	mux := NewServeMux()
+	mux.HandleFunc("/200", handler200)
+	mux.HandleFunc("/500", handler500)
+
+	srv1.Config.Handler = mux
+	srv2.Config.Handler = mux
+
+	client := WrapClient(&http.Client{})
+
+	req, err := http.NewRequest(http.MethodGet, srv1.URL+"/200", nil)
+	require.NoError(t, err)
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+	defer resp.Body.Close()
+
+	req, err = http.NewRequest(http.MethodGet, srv2.URL+"/200", nil)
+	require.NoError(t, err)
+	resp, err = client.Do(req)
+	require.NoError(t, err)
+	defer resp.Body.Close()
+
+	spans := mt.FinishedSpans()
+	require.Len(t, spans, 4)
+
+	spanSrv1 := spans[0]
+	spanClient1 := spans[1]
+	spanSrv2 := spans[2]
+	spanClient2 := spans[3]
+
+	assert.Equal(t, "server", spanSrv1.Tag("span.kind"))
+	assert.Equal(t, "server", spanSrv2.Tag("span.kind"))
+	assert.Equal(t, "client", spanClient1.Tag("span.kind"))
+	assert.Equal(t, "client", spanClient2.Tag("span.kind"))
+
+	// server1
+	assert.Equal(t, "val1", spanSrv1.Tag("tag1"), "server1 missing tag1")
+	assert.Nil(t, spanSrv1.Tag("tag2"), "server1 should not have tag2")
+
+	// client1
+	assert.Nil(t, spanClient1.Tag("tag1"), "client should not have tag1")
+	assert.Nil(t, spanClient1.Tag("tag2"), "client should not have tag2")
+
+	// server2
+	assert.Nil(t, spanSrv2.Tag("tag1"), "server2 should not have tag1")
+	assert.Equal(t, "val2", spanSrv2.Tag("tag2"), "server2 missing tag2")
+
+	// client2
+	assert.Equal(t, "val1", spanClient2.Tag("tag1"), "client2 missing tag1")
+	assert.Nil(t, spanClient2.Tag("tag2"), "client2 should not have tag2")
+}

ddtrace/tracer/option.go

@@ -308,6 +308,9 @@ type config struct {
 
 	// traceRateLimitPerSecond specifies the rate limit for traces.
 	traceRateLimitPerSecond float64
+
+	// integrationTags allows to set custom tags on integrations.
+	integrationTags []internal.IntegrationTagsRule
 }
 
 // orchestrionConfig contains Orchestrion configuration.
@@ -605,6 +608,16 @@ func newConfig(opts ...StartOption) *config {
 		c.runtimeMetricsV2 = false
 	}
 
+	if iTagsStr := os.Getenv("DD_TRACE_INTEGRATION_TAGS"); iTagsStr != "" {
+		var iTagsRules []internal.IntegrationTagsRule
+		if err := json.Unmarshal([]byte(iTagsStr), &iTagsRules); err != nil {
+			log.Warn("failed to parse DD_TRACE_INTEGRATION_TAGS: %v", err)
+		} else {
+			c.integrationTags = iTagsRules
+			globalconfig.SetIntegrationTagsRules(iTagsRules)
+		}
+	}
+
 	return c
 }
 

internal/globalconfig/globalconfig.go

@@ -20,16 +20,21 @@ var cfg = &config{
 	analyticsRate: math.NaN(),
 	runtimeID:     uuid.New().String(),
 	headersAsTags: internal.NewLockMap(map[string]string{}),
+	integrationTags: &internal.IntegrationTags{
+		Rules: nil,
+		Cache: make(map[string]map[string]string),
+	},
 }
 
 type config struct {
-	mu            sync.RWMutex
-	analyticsRate float64
-	serviceName   string
-	runtimeID     string
-	headersAsTags *internal.LockMap
-	dogstatsdAddr string
-	statsTags     []string
+	mu              sync.RWMutex
+	analyticsRate   float64
+	serviceName     string
+	runtimeID       string
+	headersAsTags   *internal.LockMap
+	dogstatsdAddr   string
+	statsTags       []string
+	integrationTags *internal.IntegrationTags
 }
 
 // AnalyticsRate returns the sampling rate at which events should be marked. It uses
@@ -130,3 +135,15 @@ func HeaderTagsLen() int {
 func ClearHeaderTags() {
 	cfg.headersAsTags.Clear()
 }
+
+func SetIntegrationTagsRules(rules []internal.IntegrationTagsRule) {
+	cfg.mu.Lock()
+	defer cfg.mu.Unlock()
+	cfg.integrationTags.Rules = rules
+}
+
+func IntegrationTags() *internal.IntegrationTags {
+	cfg.mu.RLock()
+	defer cfg.mu.RUnlock()
+	return cfg.integrationTags
+}