Fix serverClientIp function that panic on non RouteHandler scope.

foxtrace.go

@@ -1,8 +1,10 @@
 package otelfox
 
 import (
+	"errors"
 	"fmt"
 	"github.com/tigerwill90/fox"
+	"github.com/tigerwill90/otelfox/internal/clientip"
 	"github.com/tigerwill90/otelfox/internal/semconvutil"
 	semconv "go.opentelemetry.io/otel/semconv/v1.20.0"
 	"go.opentelemetry.io/otel/trace"
@@ -12,40 +14,35 @@ const (
 	tracerName = "github.com/tigerwill90/otelfox"
 )
 
-// Tracer is a Fox middleware that traces HTTP requests using OpenTelemetry.
-type Tracer struct {
+type middleware struct {
 	tracer  trace.Tracer
 	cfg     *config
 	service string
 }
 
-// New creates a new [Tracer] middleware for the given service.
-// Options can be provided to configure the tracer.
-func New(service string, opts ...Option) *Tracer {
+// Middleware returns middleware that will trace incoming requests.
+// The service parameter should describe the name of the (virtual)
+// server handling the request.
+func Middleware(service string, opts ...Option) fox.MiddlewareFunc {
+	tracer := createTracer(service, opts...)
+	return tracer.trace
+}
+
+func createTracer(service string, opts ...Option) middleware {
 	cfg := defaultConfig()
 	for _, opt := range opts {
 		opt.apply(cfg)
 	}
 
 	tracer := cfg.provider.Tracer(tracerName, trace.WithInstrumentationVersion(SemVersion()))
-	return &Tracer{
+	return middleware{
 		service: service,
 		tracer:  tracer,
 		cfg:     cfg,
 	}
 }
 
-// Middleware is a convenience function that creates a new [Tracer] middleware instance
-// for the specified service and returns the Trace middleware function.
-// Options can be provided to configure the tracer.
-func Middleware(service string, opts ...Option) fox.MiddlewareFunc {
-	tracer := New(service, opts...)
-	return tracer.Trace
-}
-
-// Trace is a middleware function that wraps the provided HandlerFunc with tracing capabilities.
-// It captures and records HTTP request information using OpenTelemetry.
-func (t *Tracer) Trace(next fox.HandlerFunc) fox.HandlerFunc {
+func (t middleware) trace(next fox.HandlerFunc) fox.HandlerFunc {
 	return func(c fox.Context) {
 
 		req := c.Request()
@@ -111,18 +108,24 @@ func (t *Tracer) Trace(next fox.HandlerFunc) fox.HandlerFunc {
 	}
 }
 
-func (t *Tracer) serverClientIP(c fox.Context) string {
-	if c.Route().ClientIPResolverEnabled() {
-		ipAddr, err := c.ClientIP()
+func (t middleware) serverClientIP(c fox.Context) string {
+	if t.cfg.resolver != nil {
+		ipAddr, err := t.cfg.resolver.ClientIP(c)
 		if err != nil {
 			return ""
 		}
 		return ipAddr.String()
 	}
 
-	ipAddr, err := t.cfg.resolver.ClientIP(c)
-	if err != nil {
-		return ""
+	ipAddr, err := c.ClientIP()
+	if err == nil {
+		return ipAddr.String()
+	}
+	if errors.Is(err, fox.ErrNoClientIPResolver) {
+		ipAddr, err = clientip.DefaultResolver.ClientIP(c)
+		if err == nil {
+			return ipAddr.String()
+		}
 	}
-	return ipAddr.String()
+	return ""
 }

foxtrace_test.go

@@ -51,14 +51,15 @@ func TestPropagationWithGlobalPropagators(t *testing.T) {
 	ctx, _ = provider.Tracer(tracerName).Start(ctx, "test")
 	otel.GetTextMapPropagator().Inject(ctx, propagation.HeaderCarrier(r.Header))
 
-	f, err := fox.New()
+	f, err := fox.New(
+		fox.WithMiddleware(Middleware("foobar", WithTracerProvider(provider))),
+	)
 	require.NoError(t, err)
-	mw := New("foobar", WithTracerProvider(provider))
-	_, err = f.Handle(http.MethodGet, "/user/{id}", mw.Trace(func(c fox.Context) {
+	_, err = f.Handle(http.MethodGet, "/user/{id}", func(c fox.Context) {
 		span := trace.SpanFromContext(c.Request().Context())
 		assert.Equal(t, sc.TraceID(), span.SpanContext().TraceID())
 		assert.Equal(t, sc.SpanID(), span.SpanContext().SpanID())
-	}))
+	})
 
 	require.NoError(t, err)
 	f.ServeHTTP(w, r)
@@ -80,18 +81,50 @@ func TestPropagationWithCustomPropagators(t *testing.T) {
 	ctx, _ = provider.Tracer(tracerName).Start(ctx, "test")
 	b3.Inject(ctx, propagation.HeaderCarrier(r.Header))
 
-	f, err := fox.New()
+	f, err := fox.New(
+		fox.WithMiddleware(Middleware("foobar", WithTracerProvider(provider), WithPropagators(b3))),
+	)
 	require.NoError(t, err)
-	mw := New("foobar", WithTracerProvider(provider), WithPropagators(b3))
-	_, err = f.Handle(http.MethodGet, "/user/{id}", mw.Trace(func(c fox.Context) {
+
+	_, err = f.Handle(http.MethodGet, "/user/{id}", func(c fox.Context) {
 		span := trace.SpanFromContext(c.Request().Context())
 		assert.Equal(t, sc.TraceID(), span.SpanContext().TraceID())
 		assert.Equal(t, sc.SpanID(), span.SpanContext().SpanID())
-	}))
+	})
 	require.NoError(t, err)
 	f.ServeHTTP(w, r)
 }
 
+func TestWithDefaultClientIPResolver(t *testing.T) {
+	provider := noop.NewTracerProvider()
+	otel.SetTextMapPropagator(b3prop.New())
+	r := httptest.NewRequest("GET", "/foo", nil)
+	r.Header.Set(fox.HeaderXForwardedFor, "25.13.12.11")
+	w := httptest.NewRecorder()
+
+	ctx := context.Background()
+	sc := trace.NewSpanContext(trace.SpanContextConfig{
+		TraceID: trace.TraceID{0x01},
+		SpanID:  trace.SpanID{0x01},
+	})
+	ctx = trace.ContextWithRemoteSpanContext(ctx, sc)
+	ctx, _ = provider.Tracer(tracerName).Start(ctx, "test")
+	otel.GetTextMapPropagator().Inject(ctx, propagation.HeaderCarrier(r.Header))
+
+	// Test with the default resolver
+	f, err := fox.New(
+		fox.WithMiddleware(Middleware("foobar", WithTracerProvider(provider))),
+	)
+	require.NoError(t, err)
+	_, err = f.Handle(http.MethodGet, "/bar", func(c fox.Context) {
+		t.Fail()
+	})
+	require.NoError(t, err)
+	assert.NotPanics(t, func() {
+		f.ServeHTTP(w, r)
+	})
+}
+
 func TestWithSpanAttributes(t *testing.T) {
 	provider := noop.NewTracerProvider()
 	otel.SetTextMapPropagator(b3prop.New())
@@ -108,24 +141,27 @@ func TestWithSpanAttributes(t *testing.T) {
 	ctx, _ = provider.Tracer(tracerName).Start(ctx, "test")
 	otel.GetTextMapPropagator().Inject(ctx, propagation.HeaderCarrier(r.Header))
 
-	f, err := fox.New()
+	f, err := fox.New(
+		fox.WithMiddleware(
+			Middleware("foobar", WithTracerProvider(provider), WithSpanAttributes(func(c fox.Context) []attribute.KeyValue {
+				attrs := make([]attribute.KeyValue, 1, 2)
+				attrs[0] = attribute.String("http.target", r.URL.String())
+				v := c.Route().Annotation("annotation")
+				attrs = append(attrs, attribute.KeyValue{
+					Key:   "annotation",
+					Value: attribute.StringValue(v.(string)),
+				})
+				return attrs
+			})),
+		),
+	)
 	require.NoError(t, err)
-	mw := New("foobar", WithTracerProvider(provider), WithSpanAttributes(func(c fox.Context) []attribute.KeyValue {
-		attrs := make([]attribute.KeyValue, 1, 2)
-		attrs[0] = attribute.String("http.target", r.URL.String())
-		v := c.Route().Annotation("annotation")
-		attrs = append(attrs, attribute.KeyValue{
-			Key:   "annotation",
-			Value: attribute.StringValue(v.(string)),
-		})
-		return attrs
-	}))
-	_, err = f.Handle(http.MethodGet, "/user/{id}", mw.Trace(func(c fox.Context) {
+	_, err = f.Handle(http.MethodGet, "/user/{id}", func(c fox.Context) {
 		span := trace.SpanFromContext(c.Request().Context())
 		assert.Equal(t, sc.TraceID(), span.SpanContext().TraceID())
 		assert.Equal(t, sc.SpanID(), span.SpanContext().SpanID())
-	}), fox.WithAnnotation("annotation", "foobar"))
-
+	}, fox.WithAnnotation("annotation", "foobar"))
 	require.NoError(t, err)
+
 	f.ServeHTTP(w, r)
 }

go.mod

@@ -4,7 +4,7 @@ go 1.23.0
 
 require (
 	github.com/stretchr/testify v1.10.0
-	github.com/tigerwill90/fox v0.20.0
+	github.com/tigerwill90/fox v0.20.1
 	go.opentelemetry.io/contrib/propagators/b3 v1.34.0
 	go.opentelemetry.io/otel v1.34.0
 	go.opentelemetry.io/otel/trace v1.34.0

go.sum

@@ -19,8 +19,8 @@ github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/tigerwill90/fox v0.20.0 h1:bILdreDBwEhEoUdH3w7EL7L9yLkgd/X+oRP2o57iK2I=
-github.com/tigerwill90/fox v0.20.0/go.mod h1:j86+yFuBav3kL1V5vSV71RyN5Y5Lqu7zqxk8VG5e+CY=
+github.com/tigerwill90/fox v0.20.1 h1:rPQvN0FmyY/YlFgW/UJz5mwmofu1dAbP6DMGIuqCU8A=
+github.com/tigerwill90/fox v0.20.1/go.mod h1:j86+yFuBav3kL1V5vSV71RyN5Y5Lqu7zqxk8VG5e+CY=
 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/propagators/b3 v1.34.0 h1:9pQdCEvV/6RWQmag94D6rhU+A4rzUhYBEJ8bpscx5p8=

internal/clientip/clientip.go

@@ -0,0 +1,50 @@
+package clientip
+
+import (
+	"github.com/tigerwill90/fox"
+	"github.com/tigerwill90/fox/clientip"
+	"net"
+)
+
+var DefaultResolver = newChain(
+	must(clientip.NewLeftmostNonPrivate(clientip.XForwardedForKey, 15)),
+	must(clientip.NewLeftmostNonPrivate(clientip.ForwardedKey, 15)),
+	must(clientip.NewSingleIPHeader(fox.HeaderXRealIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderCFConnectionIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderTrueClientIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderFastClientIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderXAzureClientIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderXAppengineRemoteAddr)),
+	must(clientip.NewSingleIPHeader(fox.HeaderFlyClientIP)),
+	must(clientip.NewSingleIPHeader(fox.HeaderXAzureSocketIP)),
+	clientip.NewRemoteAddr(),
+)
+
+type chain struct {
+	resolvers []fox.ClientIPResolver
+}
+
+func newChain(resolvers ...fox.ClientIPResolver) chain {
+	return chain{resolvers: resolvers}
+}
+
+// ClientIP try to derive the client IP using this resolver chain.
+func (s chain) ClientIP(c fox.Context) (*net.IPAddr, error) {
+	var lastErr error
+	for _, sub := range s.resolvers {
+		ipAddr, err := sub.ClientIP(c)
+		if err == nil {
+			return ipAddr, nil
+		}
+		lastErr = err
+	}
+
+	return nil, lastErr
+}
+
+func must(resolver fox.ClientIPResolver, err error) fox.ClientIPResolver {
+	if err != nil {
+		panic(err)
+	}
+	return resolver
+}

option.go

@@ -2,7 +2,6 @@ package otelfox
 
 import (
 	"github.com/tigerwill90/fox"
-	"github.com/tigerwill90/fox/clientip"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/propagation"
@@ -50,19 +49,6 @@ func defaultConfig() *config {
 		carrier: func(r *http.Request) propagation.TextMapCarrier {
 			return propagation.HeaderCarrier(r.Header)
 		},
-		resolver: clientip.NewChain(
-			must(clientip.NewLeftmostNonPrivate(clientip.XForwardedForKey, 15)),
-			must(clientip.NewLeftmostNonPrivate(clientip.ForwardedKey, 15)),
-			must(clientip.NewSingleIPHeader(fox.HeaderCFConnectionIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderTrueClientIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderFastClientIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderXAzureClientIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderXAzureSocketIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderXAppengineRemoteAddr)),
-			must(clientip.NewSingleIPHeader(fox.HeaderFlyClientIP)),
-			must(clientip.NewSingleIPHeader(fox.HeaderXRealIP)),
-			clientip.NewRemoteAddr(),
-		),
 	}
 }
 
@@ -127,18 +113,12 @@ func WithSpanAttributes(fn SpanAttributesFunc) Option {
 
 // WithClientIPResolver sets a custom resolver to determine the client IP address.
 // This is for advanced use case, must user should configure the resolver with Fox's router option using
-// [fox.WithClientIPResolver].
+// [fox.WithClientIPResolver]. Note that setting a resolver here takes priority over any resolver configured
+// globally or at the route level in Fox.
 func WithClientIPResolver(resolver fox.ClientIPResolver) Option {
 	return optionFunc(func(c *config) {
 		if resolver != nil {
 			c.resolver = resolver
 		}
 	})
 }
-
-func must(resolver fox.ClientIPResolver, err error) fox.ClientIPResolver {
-	if err != nil {
-		panic(err)
-	}
-	return resolver
-}

version.go

@@ -2,7 +2,7 @@ package otelfox
 
 import "fmt"
 
-const version = "v0.20.0"
+const version = "v0.20.1"
 
 var semver = fmt.Sprintf("semver:%s", version)