use case-insensitive header keys for http probes

api/openapi-spec/swagger.json

@@ -6192,7 +6192,7 @@
       "description": "HTTPHeader describes a custom header to be used in HTTP probes",
       "properties": {
         "name": {
-          "description": "The header field name",
+          "description": "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
           "type": "string"
         },
         "value": {

api/openapi-spec/v3/api__v1_openapi.json

@@ -2632,7 +2632,7 @@
         "properties": {
           "name": {
             "default": "",
-            "description": "The header field name",
+            "description": "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
             "type": "string"
           },
           "value": {

api/openapi-spec/v3/apis__apps__v1_openapi.json

@@ -2568,7 +2568,7 @@
         "properties": {
           "name": {
             "default": "",
-            "description": "The header field name",
+            "description": "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
             "type": "string"
           },
           "value": {

api/openapi-spec/v3/apis__batch__v1_openapi.json

@@ -1859,7 +1859,7 @@
         "properties": {
           "name": {
             "default": "",
-            "description": "The header field name",
+            "description": "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
             "type": "string"
           },
           "value": {

pkg/apis/core/types.go

@@ -2037,7 +2037,8 @@ type SecretEnvSource struct {
 
 // HTTPHeader describes a custom header to be used in HTTP probes
 type HTTPHeader struct {
-	// The header field name
+	// The header field name.
+	// This will be canonicalized upon output, so case-variant names will be understood as the same header.
 	Name string
 	// The header field value
 	Value string

pkg/generated/openapi/zz_generated.openapi.go

@@ -19979,7 +19979,7 @@ func schema_k8sio_api_core_v1_HTTPHeader(ref common.ReferenceCallback) common.Op
 				Properties: map[string]spec.Schema{
 					"name": {
 						SchemaProps: spec.SchemaProps{
-							Description: "The header field name",
+							Description: "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
 							Default:     "",
 							Type:        []string{"string"},
 							Format:      "",

pkg/probe/http/request.go

@@ -113,7 +113,7 @@ func formatURL(scheme string, host string, port int, path string) *url.URL {
 func v1HeaderToHTTPHeader(headerList []v1.HTTPHeader) http.Header {
 	headers := make(http.Header)
 	for _, header := range headerList {
-		headers[header.Name] = append(headers[header.Name], header.Value)
+		headers.Add(header.Name, header.Value)
 	}
 	return headers
 }

pkg/probe/http/request_test.go

@@ -64,6 +64,17 @@ func Test_v1HeaderToHTTPHeader(t *testing.T) {
 				"Accept-Ranges": {"bytes"},
 			},
 		},
+		{
+			name: "case insensitive",
+			headerList: []v1.HTTPHeader{
+				{Name: "HOST", Value: "example.com"},
+				{Name: "FOO-bAR", Value: "value"},
+			},
+			want: http.Header{
+				"Host":    {"example.com"},
+				"Foo-Bar": {"value"},
+			},
+		},
 		{
 			name:       "empty input",
 			headerList: []v1.HTTPHeader{},

staging/src/k8s.io/api/core/v1/generated.proto

@@ -1853,7 +1853,8 @@ message HTTPGetAction {
 
 // HTTPHeader describes a custom header to be used in HTTP probes
 message HTTPHeader {
-  // The header field name
+  // The header field name.
+  // This will be canonicalized upon output, so case-variant names will be understood as the same header.
   optional string name = 1;
 
   // The header field value

staging/src/k8s.io/api/core/v1/types.go

@@ -2137,7 +2137,8 @@ type SecretEnvSource struct {
 
 // HTTPHeader describes a custom header to be used in HTTP probes
 type HTTPHeader struct {
-	// The header field name
+	// The header field name.
+	// This will be canonicalized upon output, so case-variant names will be understood as the same header.
 	Name string `json:"name" protobuf:"bytes,1,opt,name=name"`
 	// The header field value
 	Value string `json:"value" protobuf:"bytes,2,opt,name=value"`

staging/src/k8s.io/api/core/v1/types_swagger_doc_generated.go

@@ -832,7 +832,7 @@ func (HTTPGetAction) SwaggerDoc() map[string]string {
 
 var map_HTTPHeader = map[string]string{
 	"":      "HTTPHeader describes a custom header to be used in HTTP probes",
-	"name":  "The header field name",
+	"name":  "The header field name. This will be canonicalized upon output, so case-variant names will be understood as the same header.",
 	"value": "The header field value",
 }