Add custom response headers for backend service

.changelog/4223.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement 
+compute: added `custom_response_headers` field to `google_compute_backend_service` resource
+```

google/resource_compute_backend_service.go

@@ -466,6 +466,16 @@ requests.`,
 				},
 				Set: schema.HashString,
 			},
+			"custom_response_headers": {
+				Type:     schema.TypeSet,
+				Optional: true,
+				Description: `Headers that the HTTP/S load balancer should add to proxied
+responses.`,
+				Elem: &schema.Schema{
+					Type: schema.TypeString,
+				},
+				Set: schema.HashString,
+			},
 			"description": {
 				Type:        schema.TypeString,
 				Optional:    true,
@@ -978,6 +988,12 @@ func resourceComputeBackendServiceCreate(d *schema.ResourceData, meta interface{
 	} else if v, ok := d.GetOkExists("custom_request_headers"); !isEmptyValue(reflect.ValueOf(customRequestHeadersProp)) && (ok || !reflect.DeepEqual(v, customRequestHeadersProp)) {
 		obj["customRequestHeaders"] = customRequestHeadersProp
 	}
+	customResponseHeadersProp, err := expandComputeBackendServiceCustomResponseHeaders(d.Get("custom_response_headers"), d, config)
+	if err != nil {
+		return err
+	} else if v, ok := d.GetOkExists("custom_response_headers"); !isEmptyValue(reflect.ValueOf(customResponseHeadersProp)) && (ok || !reflect.DeepEqual(v, customResponseHeadersProp)) {
+		obj["customResponseHeaders"] = customResponseHeadersProp
+	}
 	fingerprintProp, err := expandComputeBackendServiceFingerprint(d.Get("fingerprint"), d, config)
 	if err != nil {
 		return err
@@ -1222,6 +1238,9 @@ func resourceComputeBackendServiceRead(d *schema.ResourceData, meta interface{})
 	if err := d.Set("custom_request_headers", flattenComputeBackendServiceCustomRequestHeaders(res["customRequestHeaders"], d, config)); err != nil {
 		return fmt.Errorf("Error reading BackendService: %s", err)
 	}
+	if err := d.Set("custom_response_headers", flattenComputeBackendServiceCustomResponseHeaders(res["customResponseHeaders"], d, config)); err != nil {
+		return fmt.Errorf("Error reading BackendService: %s", err)
+	}
 	if err := d.Set("fingerprint", flattenComputeBackendServiceFingerprint(res["fingerprint"], d, config)); err != nil {
 		return fmt.Errorf("Error reading BackendService: %s", err)
 	}
@@ -1332,6 +1351,12 @@ func resourceComputeBackendServiceUpdate(d *schema.ResourceData, meta interface{
 	} else if v, ok := d.GetOkExists("custom_request_headers"); !isEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, customRequestHeadersProp)) {
 		obj["customRequestHeaders"] = customRequestHeadersProp
 	}
+	customResponseHeadersProp, err := expandComputeBackendServiceCustomResponseHeaders(d.Get("custom_response_headers"), d, config)
+	if err != nil {
+		return err
+	} else if v, ok := d.GetOkExists("custom_response_headers"); !isEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, customResponseHeadersProp)) {
+		obj["customResponseHeaders"] = customResponseHeadersProp
+	}
 	fingerprintProp, err := expandComputeBackendServiceFingerprint(d.Get("fingerprint"), d, config)
 	if err != nil {
 		return err
@@ -2025,6 +2050,13 @@ func flattenComputeBackendServiceCustomRequestHeaders(v interface{}, d *schema.R
 	return schema.NewSet(schema.HashString, v.([]interface{}))
 }
 
+func flattenComputeBackendServiceCustomResponseHeaders(v interface{}, d *schema.ResourceData, config *Config) interface{} {
+	if v == nil {
+		return v
+	}
+	return schema.NewSet(schema.HashString, v.([]interface{}))
+}
+
 func flattenComputeBackendServiceFingerprint(v interface{}, d *schema.ResourceData, config *Config) interface{} {
 	return v
 }
@@ -2869,6 +2901,11 @@ func expandComputeBackendServiceCustomRequestHeaders(v interface{}, d TerraformR
 	return v, nil
 }
 
+func expandComputeBackendServiceCustomResponseHeaders(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
+	v = v.(*schema.Set).List()
+	return v, nil
+}
+
 func expandComputeBackendServiceFingerprint(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
 	return v, nil
 }

google/resource_compute_backend_service_generated_test.go

@@ -114,6 +114,7 @@ resource "google_compute_backend_service" "default" {
   connection_draining_timeout_sec = 10
 
   custom_request_headers          = ["host: ${google_compute_global_network_endpoint.proxy.fqdn}"]
+  custom_response_headers         = ["X-Cache-Hit: {cdn_cache_status}"]
 
   backend {
     group = google_compute_global_network_endpoint_group.external_proxy.id

google/resource_compute_backend_service_test.go

@@ -1343,6 +1343,7 @@ resource "google_compute_backend_service" "foobar" {
   health_checks = [google_compute_http_health_check.zero.self_link]
 
   custom_request_headers = ["Client-Region: {client_region}", "Client-Rtt: {client_rtt_msec}"]
+  custom_response_headers = ["X-Cache-Hit: {cdn_cache_status}", "X-Cache-Id: {cdn_cache_id}"]
 }
 
 resource "google_compute_http_health_check" "zero" {

website/docs/r/compute_backend_service.html.markdown

@@ -159,6 +159,7 @@ resource "google_compute_backend_service" "default" {
   connection_draining_timeout_sec = 10
 
   custom_request_headers          = ["host: ${google_compute_global_network_endpoint.proxy.fqdn}"]
+  custom_response_headers         = ["X-Cache-Hit: {cdn_cache_status}"]
 
   backend {
     group = google_compute_global_network_endpoint_group.external_proxy.id
@@ -231,6 +232,11 @@ The following arguments are supported:
   Headers that the HTTP/S load balancer should add to proxied
   requests.
 
+* `custom_response_headers` -
+  (Optional)
+  Headers that the HTTP/S load balancer should add to proxied
+  responses.
+
 * `description` -
   (Optional)
   An optional description of this resource.