feat(http): propagate traceparent for httpclient

Co-authored-by: tronghn <trong.huu.nguyen@nav.no>

go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/spf13/viper v1.19.0
 	github.com/stretchr/testify v1.10.0
 	github.com/uptrace/opentelemetry-go-extra/otellogrus v0.3.2
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0
 	go.opentelemetry.io/otel v1.34.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.34.0
 	go.opentelemetry.io/otel/sdk v1.34.0

go.sum

@@ -158,6 +158,8 @@ github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M
 github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
 go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 h1:jq9TW8u3so/bN+JPT166wjOI6/vQPF6Xe7nMNIltagk=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0/go.mod h1:p8pYQP+m5XfbZm9fxtSKAbM6oIllS7s2AfxrChvc7iw=
 go.opentelemetry.io/otel v1.34.0 h1:zRLXxLCgL1WyKsPVrgbSdMN4c0FMkDAskSTQP+0hdUY=
 go.opentelemetry.io/otel v1.34.0/go.mod h1:OWFPOQ+h4G8xpyjgqo4SxJYdDQ/qmRH+wivy7zzx9oI=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.34.0 h1:OeNbIYk/2C15ckl7glBlOBp5+WlYsOElzTNmiPW/x60=

internal/http/transport.go

@@ -0,0 +1,27 @@
+package http
+
+import (
+	"net/http"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+)
+
+var (
+	defaultTransport *http.Transport
+	once             sync.Once
+)
+
+func Transport() http.RoundTripper {
+	once.Do(func() {
+		t := http.DefaultTransport.(*http.Transport).Clone()
+		t.MaxIdleConns = 200
+		t.MaxIdleConnsPerHost = 100
+		t.IdleConnTimeout = 5 * time.Second
+
+		defaultTransport = t
+	})
+
+	return otelhttp.NewTransport(defaultTransport)
+}

pkg/handler/reverseproxy.go

@@ -14,7 +14,6 @@ import (
 	"github.com/nais/wonderwall/pkg/handler/acr"
 	"github.com/nais/wonderwall/pkg/handler/autologin"
 	mw "github.com/nais/wonderwall/pkg/middleware"
-	"github.com/nais/wonderwall/pkg/server"
 	"github.com/nais/wonderwall/pkg/session"
 	"github.com/nais/wonderwall/pkg/url"
 )
@@ -76,7 +75,7 @@ func NewReverseProxy(upstream *urllib.URL, preserveInboundHostHeader bool) *Reve
 				r.Out.Header.Set("X-Wonderwall-Id-Token", idToken)
 			}
 		},
-		Transport: server.DefaultTransport(),
+		Transport: httpinternal.Transport(),
 	}
 	return &ReverseProxy{
 		ReverseProxy: rp,

pkg/openid/client/client.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"time"
 
+	httpinternal "github.com/nais/wonderwall/internal/http"
+
 	"github.com/google/uuid"
 	"github.com/lestrrat-go/jwx/v2/jwk"
 	"github.com/lestrrat-go/jwx/v2/jwt"
@@ -17,7 +19,6 @@ import (
 
 	"github.com/nais/wonderwall/pkg/openid"
 	openidconfig "github.com/nais/wonderwall/pkg/openid/config"
-	"github.com/nais/wonderwall/pkg/server"
 	urlpkg "github.com/nais/wonderwall/pkg/url"
 )
 
@@ -55,7 +56,7 @@ func NewClient(cfg openidconfig.Config, jwksProvider JwksProvider) *Client {
 
 	httpClient := &http.Client{
 		Timeout:   time.Second * 10,
-		Transport: server.DefaultTransport(),
+		Transport: httpinternal.Transport(),
 	}
 
 	return &Client{

pkg/server/server.go

@@ -6,7 +6,6 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
-	"sync"
 	"syscall"
 	"time"
 
@@ -16,25 +15,6 @@ import (
 	"github.com/nais/wonderwall/pkg/config"
 )
 
-var (
-	defaultTransport *http.Transport
-	once             sync.Once
-)
-
-// TODO: use otel to propagate trace_id
-func DefaultTransport() *http.Transport {
-	once.Do(func() {
-		t := http.DefaultTransport.(*http.Transport).Clone()
-		t.MaxIdleConns = 200
-		t.MaxIdleConnsPerHost = 100
-		t.IdleConnTimeout = 5 * time.Second
-
-		defaultTransport = t
-	})
-
-	return defaultTransport
-}
-
 func Start(cfg *config.Config, r chi.Router) error {
 	server := http.Server{
 		Addr:    cfg.BindAddress,