jaegerremote: Add WithSamplingStrategyFetcher option

CHANGELOG.md

@@ -11,6 +11,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Added
 
 - Add the new `go.opentelemetry.io/contrib/instrgen` package to provide auto-generated source code instrumentation. (#3068, #3108)
+- Add `WithSamplingStrategyFetcher` which sets custom fetcher implementation. (#4045)
+
+### Fixed
+
+- Fixed panic when default HTTP round-tripper is not `*http.Transport` (#4045)
 
 ## [1.18.0/0.43.0/0.12.0] - 2023-08-28
 
@@ -19,7 +24,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add `NewMiddleware` function in `go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp`. (#2964)
 - The `go.opentelemetry.io/contrib/exporters/autoexport` package to provide configuration of trace exporters with useful defaults and environment variable support. (#2753, #4100, #4130, #4132, #4134)
 - `WithRouteTag` in `go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp` adds HTTP route attribute to metrics. (#615)
-- Add `WithSamplingStrategyFetcher` which sets custom fetcher implementation. Fixed panic when default HTTP round-tripper is not `*http.Transport` (#4045)
+
 - Add `WithSpanOptions` option in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. (#3768)
 - Add testing support for Go 1.21. (#4233)
 

samplers/jaegerremote/sampler_remote.go

@@ -273,20 +273,12 @@ type httpSamplingStrategyFetcher struct {
 }
 
 func newHTTPSamplingStrategyFetcher(serverURL string) *httpSamplingStrategyFetcher {
-	fetcher := &httpSamplingStrategyFetcher{
+	return &httpSamplingStrategyFetcher{
 		serverURL: serverURL,
+		httpClient: http.Client{
+			Timeout: defaultRemoteSamplingTimeout,
+		},
 	}
-
-	if customTransport, ok := http.DefaultTransport.(*http.Transport); ok {
-		customTransport = customTransport.Clone()
-		customTransport.ResponseHeaderTimeout = defaultRemoteSamplingTimeout
-
-		fetcher.httpClient = http.Client{
-			Transport: customTransport.Clone(),
-		}
-	}
-
-	return fetcher
 }
 
 func (f *httpSamplingStrategyFetcher) Fetch(serviceName string) ([]byte, error) {

samplers/jaegerremote/sampler_remote_test.go

@@ -590,10 +590,7 @@ func TestSamplingStrategyParserImpl_Error(t *testing.T) {
 
 func TestDefaultSamplingStrategyFetcher_Timeout(t *testing.T) {
 	fetcher := newHTTPSamplingStrategyFetcher("")
-
-	customTransport, ok := fetcher.httpClient.Transport.(*http.Transport)
-	require.True(t, ok)
-	assert.Equal(t, defaultRemoteSamplingTimeout, customTransport.ResponseHeaderTimeout)
+	assert.Equal(t, defaultRemoteSamplingTimeout, fetcher.httpClient.Timeout)
 }
 
 func TestDefaultSamplingStrategyFetcher_NoPanic(t *testing.T) {