improve IAM module

Signed-off-by: hongming <talonwan@yunify.com>

vendor/k8s.io/apiserver/pkg/endpoints/handlers/helpers.go

@@ -0,0 +1,60 @@
+/*
+Copyright 2019 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 handlers
+
+import (
+	"net/http"
+
+	utilnet "k8s.io/apimachinery/pkg/util/net"
+)
+
+const (
+	maxUserAgentLength      = 1024
+	userAgentTruncateSuffix = "...TRUNCATED"
+)
+
+// lazyTruncatedUserAgent implements String() string and it will
+// return user-agent which may be truncated.
+type lazyTruncatedUserAgent struct {
+	req *http.Request
+}
+
+func (lazy *lazyTruncatedUserAgent) String() string {
+	ua := "unknown"
+	if lazy.req != nil {
+		ua = utilnet.GetHTTPClient(lazy.req)
+		if len(ua) > maxUserAgentLength {
+			ua = ua[:maxUserAgentLength] + userAgentTruncateSuffix
+		}
+	}
+	return ua
+}
+
+// LazyClientIP implements String() string and it will
+// calls GetClientIP() lazily only when required.
+type lazyClientIP struct {
+	req *http.Request
+}
+
+func (lazy *lazyClientIP) String() string {
+	if lazy.req != nil {
+		if ip := utilnet.GetClientIP(lazy.req); ip != nil {
+			return ip.String()
+		}
+	}
+	return "unknown"
+}