feat(all): Add ability to specify []otelhttp.Opts for transport when create new HTTP client

Author: surik

internal/settings.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"cloud.google.com/go/auth"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/internal/impersonate"
@@ -76,6 +77,9 @@ type DialSettings struct {
 
 	// TODO(b/372244283): Remove after b/358175516 has been fixed
 	EnableAsyncRefreshDryRun func()
+
+	// otelhttp options
+	OtelHTTPOpts []otelhttp.Option
 }
 
 // GetScopes returns the user-provided scopes, if set, or else falls back to the

option/option.go

@@ -11,6 +11,7 @@ import (
 	"net/http"
 
 	"cloud.google.com/go/auth"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/internal"
@@ -414,3 +415,17 @@ type withLogger struct{ l *slog.Logger }
 func (w withLogger) Apply(o *internal.DialSettings) {
 	o.Logger = w.l
 }
+
+// WithOtelHTTPOpts returns a ClientOption that sets the options for
+// the OpenTelemetry HTTP client. This option is used to configure
+// the OpenTelemetry HTTP client instrumentation.
+func WithOtelHTTPOpts(opts ...otelhttp.Option) ClientOption {
+	return withOtelHTTPOpts{opts}
+}
+
+type withOtelHTTPOpts struct{ opts []otelhttp.Option }
+
+func (w withOtelHTTPOpts) Apply(o *internal.DialSettings) {
+	o.OtelHTTPOpts = make([]otelhttp.Option, len(w.opts))
+	copy(o.OtelHTTPOpts, w.opts)
+}

option/option_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/internal"
 	"google.golang.org/grpc"
@@ -133,3 +134,29 @@ func TestApplyClientCertSource(t *testing.T) {
 		t.Error(cmp.Diff(certGot, certWant, cmpopts.IgnoreUnexported(big.Int{}), cmpopts.IgnoreFields(tls.Certificate{}, "Leaf")))
 	}
 }
+
+func TestOtelHTTPOpts(t *testing.T) {
+	otelhttpopts := []otelhttp.Option{
+		otelhttp.WithServerName("test"),
+	}
+	opts := []ClientOption{
+		WithOtelHTTPOpts(otelhttpopts...),
+	}
+	var got internal.DialSettings
+	for _, opt := range opts {
+		opt.Apply(&got)
+	}
+	want := internal.DialSettings{
+		OtelHTTPOpts: []otelhttp.Option{
+			otelhttp.WithServerName("test"),
+		},
+	}
+
+	comparer := cmp.Comparer(func(x, y internal.DialSettings) bool {
+		return len(x.OtelHTTPOpts) == len(y.OtelHTTPOpts)
+	})
+
+	if !cmp.Equal(got, want, comparer) {
+		t.Error(cmp.Diff(got, want, comparer))
+	}
+}

transport/http/dial.go

@@ -306,7 +306,7 @@ func addOpenTelemetryTransport(trans http.RoundTripper, settings *internal.DialS
 	if settings.TelemetryDisabled {
 		return trans
 	}
-	return otelhttp.NewTransport(trans)
+	return otelhttp.NewTransport(trans, settings.OtelHTTPOpts...)
 }
 
 // clonedTransport returns the given RoundTripper as a cloned *http.Transport.