chore: configure timeouts for HTTP/2 (#8388)

And add a unit test for the default transport.

Author: feiskyer

pkg/azclient/utils/transport.go

@@ -22,8 +22,11 @@ import (
 	"net/http"
 	"sync"
 	"time"
+
+	"golang.org/x/net/http2"
 )
 
+// DefaultTransport is the default transport used by the Azure SDK for Go.
 var DefaultTransport *http.Transport
 var once sync.Once
 
@@ -44,5 +47,11 @@ func init() {
 				MinVersion: tls.VersionTLS12,
 			},
 		}
+
+		// Configure HTTP/2
+		if http2Transport, err := http2.ConfigureTransports(DefaultTransport); err == nil {
+			http2Transport.ReadIdleTimeout = 30 * time.Second
+			http2Transport.PingTimeout = 15 * time.Second
+		}
 	})
 }

pkg/azclient/utils/transport_test.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"crypto/tls"
+	"testing"
+	"time"
+)
+
+func TestDefaultTransport(t *testing.T) {
+	if DefaultTransport == nil {
+		t.Fatal("DefaultTransport is nil")
+	}
+
+	if DefaultTransport.DialContext == nil {
+		t.Error("DialContext is nil")
+	}
+
+	if !DefaultTransport.ForceAttemptHTTP2 {
+		t.Error("ForceAttemptHTTP2 is false")
+	}
+
+	if DefaultTransport.MaxIdleConns != 100 {
+		t.Errorf("Expected MaxIdleConns to be 100, got %d", DefaultTransport.MaxIdleConns)
+	}
+
+	if DefaultTransport.MaxConnsPerHost != 100 {
+		t.Errorf("Expected MaxConnsPerHost to be 100, got %d", DefaultTransport.MaxConnsPerHost)
+	}
+
+	if DefaultTransport.IdleConnTimeout != 90*time.Second {
+		t.Errorf("Expected IdleConnTimeout to be 90s, got %v", DefaultTransport.IdleConnTimeout)
+	}
+
+	if DefaultTransport.TLSHandshakeTimeout != 10*time.Second {
+		t.Errorf("Expected TLSHandshakeTimeout to be 10s, got %v", DefaultTransport.TLSHandshakeTimeout)
+	}
+
+	if DefaultTransport.ExpectContinueTimeout != 1*time.Second {
+		t.Errorf("Expected ExpectContinueTimeout to be 1s, got %v", DefaultTransport.ExpectContinueTimeout)
+	}
+
+	if DefaultTransport.ResponseHeaderTimeout != 60*time.Second {
+		t.Errorf("Expected ResponseHeaderTimeout to be 60s, got %v", DefaultTransport.ResponseHeaderTimeout)
+	}
+
+	if DefaultTransport.TLSClientConfig == nil {
+		t.Fatal("TLSClientConfig is nil")
+	}
+
+	if DefaultTransport.TLSClientConfig.MinVersion != tls.VersionTLS12 {
+		t.Errorf("Expected MinVersion to be TLS1.2, got %v", DefaultTransport.TLSClientConfig.MinVersion)
+	}
+
+	if DefaultTransport.TLSClientConfig.Renegotiation != tls.RenegotiateNever {
+		t.Errorf("Expected Renegotiation to be RenegotiateNever, got %v", DefaultTransport.TLSClientConfig.Renegotiation)
+	}
+
+	// NOTE: http2 transport settings are not exposed hence testing is skipped.
+}