close tikv#4490: fix exported var problem

Signed-off-by: Cabinfever_B <cabinfeveroier@gmail.com>

pkg/apiutil/apiutil.go

@@ -28,11 +28,11 @@ import (
 )
 
 var (
-	// ComponentSignatureKey is used for http request header key
+	// componentSignatureKey is used for http request header key
 	// to identify component signature
-	ComponentSignatureKey = "component"
-	// ComponentAnonymousValue identifies anonymous request source
-	ComponentAnonymousValue = "anonymous"
+	componentSignatureKey = "component"
+	// componentAnonymousValue identifies anonymous request source
+	componentAnonymousValue = "anonymous"
 )
 
 // DeferClose captures the error returned from closing (if an error occurs).
@@ -138,23 +138,31 @@ func ErrorResp(rd *render.Render, w http.ResponseWriter, err error) {
 
 // GetComponentNameOnHTTP returns component name from Request Header
 func GetComponentNameOnHTTP(r *http.Request) string {
-	componentName := r.Header.Get(ComponentSignatureKey)
+	componentName := r.Header.Get(componentSignatureKey)
 	if componentName == "" {
-		componentName = ComponentAnonymousValue
+		componentName = componentAnonymousValue
 	}
 	return componentName
 }
 
 // ComponentSignatureRoundTripper is used to add component signature in HTTP header
 type ComponentSignatureRoundTripper struct {
-	Proxied   http.RoundTripper
-	Component string
+	proxied   http.RoundTripper
+	component *string
+}
+
+// NewComponentSignatureRoundTripper returns a new ComponentSignatureRoundTripper.
+func NewComponentSignatureRoundTripper(roundTripper http.RoundTripper, componentName *string) *ComponentSignatureRoundTripper {
+	return &ComponentSignatureRoundTripper{
+		proxied:   roundTripper,
+		component: componentName,
+	}
 }
 
 // RoundTrip is used to implement RoundTripper
 func (rt *ComponentSignatureRoundTripper) RoundTrip(req *http.Request) (resp *http.Response, err error) {
-	req.Header.Add(ComponentSignatureKey, rt.Component)
+	req.Header.Add(componentSignatureKey, *rt.component)
 	// Send the request, get the response and the error
-	resp, err = rt.Proxied.RoundTrip(req)
+	resp, err = rt.proxied.RoundTrip(req)
 	return
 }

tools/pd-ctl/pdctl/command/global.go

@@ -30,11 +30,9 @@ import (
 )
 
 var (
-	dialClient = &http.Client{
-		Transport: &apiutil.ComponentSignatureRoundTripper{
-			Component: "pdctl",
-			Proxied:   http.DefaultTransport,
-		},
+	pdControllerComponentName = "pdctl"
+	dialClient                = &http.Client{
+		Transport: apiutil.NewComponentSignatureRoundTripper(http.DefaultTransport, &pdControllerComponentName),
 	}
 	pingPrefix = "pd/api/v1/ping"
 )
@@ -52,11 +50,8 @@ func InitHTTPSClient(caPath, certPath, keyPath string) error {
 	}
 
 	dialClient = &http.Client{
-		Transport: &apiutil.ComponentSignatureRoundTripper{
-			Component: "pdctl",
-			Proxied: &http.Transport{
-				TLSClientConfig: tlsConfig},
-		},
+		Transport: apiutil.NewComponentSignatureRoundTripper(
+			&http.Transport{TLSClientConfig: tlsConfig}, &pdControllerComponentName),
 	}
 
 	return nil