Add Changelog entry and api package support for HTTP Header manip

.changelog/10613.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+connect: Support manipulating HTTP headers in the mesh.
+```

api/config_entry_discoverychain.go

@@ -61,14 +61,16 @@ type ServiceRouteHTTPMatchQueryParam struct {
 }
 
 type ServiceRouteDestination struct {
-	Service               string        `json:",omitempty"`
-	ServiceSubset         string        `json:",omitempty" alias:"service_subset"`
-	Namespace             string        `json:",omitempty"`
-	PrefixRewrite         string        `json:",omitempty" alias:"prefix_rewrite"`
-	RequestTimeout        time.Duration `json:",omitempty" alias:"request_timeout"`
-	NumRetries            uint32        `json:",omitempty" alias:"num_retries"`
-	RetryOnConnectFailure bool          `json:",omitempty" alias:"retry_on_connect_failure"`
-	RetryOnStatusCodes    []uint32      `json:",omitempty" alias:"retry_on_status_codes"`
+	Service               string               `json:",omitempty"`
+	ServiceSubset         string               `json:",omitempty" alias:"service_subset"`
+	Namespace             string               `json:",omitempty"`
+	PrefixRewrite         string               `json:",omitempty" alias:"prefix_rewrite"`
+	RequestTimeout        time.Duration        `json:",omitempty" alias:"request_timeout"`
+	NumRetries            uint32               `json:",omitempty" alias:"num_retries"`
+	RetryOnConnectFailure bool                 `json:",omitempty" alias:"retry_on_connect_failure"`
+	RetryOnStatusCodes    []uint32             `json:",omitempty" alias:"retry_on_status_codes"`
+	RequestHeaders        *HTTPHeaderModifiers `json:",omitempty" alias:"request_headers"`
+	ResponseHeaders       *HTTPHeaderModifiers `json:",omitempty" alias:"response_headers"`
 }
 
 func (e *ServiceRouteDestination) MarshalJSON() ([]byte, error) {
@@ -127,10 +129,12 @@ func (e *ServiceSplitterConfigEntry) GetCreateIndex() uint64     { return e.Crea
 func (e *ServiceSplitterConfigEntry) GetModifyIndex() uint64     { return e.ModifyIndex }
 
 type ServiceSplit struct {
-	Weight        float32
-	Service       string `json:",omitempty"`
-	ServiceSubset string `json:",omitempty" alias:"service_subset"`
-	Namespace     string `json:",omitempty"`
+	Weight          float32
+	Service         string               `json:",omitempty"`
+	ServiceSubset   string               `json:",omitempty" alias:"service_subset"`
+	Namespace       string               `json:",omitempty"`
+	RequestHeaders  *HTTPHeaderModifiers `json:",omitempty" alias:"request_headers"`
+	ResponseHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"response_headers"`
 }
 
 type ServiceResolverConfigEntry struct {
@@ -287,3 +291,21 @@ type CookieConfig struct {
 	// The path to set for the cookie
 	Path string `json:",omitempty"`
 }
+
+// HTTPHeaderModifiers is a set of rules for HTTP header modification that
+// should be performed by proxies as the request passes through them. It can
+// operate on either request or response headers depending on the context in
+// which it is used.
+type HTTPHeaderModifiers struct {
+	// Add is a set of name -> value pairs that should be appended to the request
+	// or response (i.e. allowing duplicates if the same header already exists).
+	Add map[string]string `json:",omitempty"`
+
+	// Set is a set of name -> value pairs that should be added to the request or
+	// response, overwriting any existing header values of the same name.
+	Set map[string]string `json:",omitempty"`
+
+	// Remove is the set of header names that should be stripped from the request
+	// or response.
+	Remove []string `json:",omitempty"`
+}

api/config_entry_discoverychain_test.go

@@ -193,6 +193,14 @@ func TestAPI_ConfigEntry_DiscoveryChain(t *testing.T) {
 						Service:       "test-failover",
 						ServiceSubset: "v1",
 						Namespace:     defaultNamespace,
+						RequestHeaders: &HTTPHeaderModifiers{
+							Set: map[string]string{
+								"x-foo": "bar",
+							},
+						},
+						ResponseHeaders: &HTTPHeaderModifiers{
+							Remove: []string{"x-foo"},
+						},
 					},
 					{
 						Weight:    10,
@@ -235,6 +243,14 @@ func TestAPI_ConfigEntry_DiscoveryChain(t *testing.T) {
 							NumRetries:            5,
 							RetryOnConnectFailure: true,
 							RetryOnStatusCodes:    []uint32{500, 503, 401},
+							RequestHeaders: &HTTPHeaderModifiers{
+								Set: map[string]string{
+									"x-foo": "bar",
+								},
+							},
+							ResponseHeaders: &HTTPHeaderModifiers{
+								Remove: []string{"x-foo"},
+							},
 						},
 					},
 				},

api/config_entry_gateways.go

@@ -83,6 +83,10 @@ type IngressService struct {
 	// using a "tcp" listener.
 	Hosts []string
 
+	// Allow HTTP header manipulation to be configured.
+	RequestHeaders  *HTTPHeaderModifiers `json:",omitempty" alias:"request_headers"`
+	ResponseHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"response_headers"`
+
 	// Namespace is the namespace where the service is located.
 	// Namespacing is a Consul Enterprise feature.
 	Namespace string `json:",omitempty"`

api/config_entry_gateways_test.go

@@ -78,6 +78,14 @@ func TestAPI_ConfigEntries_IngressGateway(t *testing.T) {
 				{
 					Name:  "asdf",
 					Hosts: []string{"test.example.com"},
+					RequestHeaders: &HTTPHeaderModifiers{
+						Set: map[string]string{
+							"x-foo": "bar",
+						},
+					},
+					ResponseHeaders: &HTTPHeaderModifiers{
+						Remove: []string{"x-foo"},
+					},
 				},
 			},
 		},