config: add support for set_response_headers in a policy (#2171)

* config: add support for set_response_headers in a policy

* docs: add note about precedence

config/envoyconfig/routes.go

@@ -276,6 +276,7 @@ func (b *Builder) buildPolicyRoutes(options *config.Options, domain string) ([]*
 			Metadata:               &envoy_config_core_v3.Metadata{},
 			RequestHeadersToAdd:    toEnvoyHeaders(policy.SetRequestHeaders),
 			RequestHeadersToRemove: getRequestHeadersToRemove(options, &policy),
+			ResponseHeadersToAdd:   toEnvoyHeaders(policy.SetResponseHeaders),
 		}
 		if policy.Redirect != nil {
 			action, err := b.buildPolicyRouteRedirectAction(policy.Redirect)

config/policy.go

@@ -151,6 +151,9 @@ type Policy struct {
 
 	// RewriteResponseHeaders rewrites response headers. This can be used to change the Location header.
 	RewriteResponseHeaders []RewriteHeader `mapstructure:"rewrite_response_headers" yaml:"rewrite_response_headers,omitempty" json:"rewrite_response_headers,omitempty"` //nolint
+
+	// SetResponseHeaders sets response headers.
+	SetResponseHeaders map[string]string `mapstructure:"set_response_headers" yaml:"set_response_headers,omitempty"`
 }
 
 // RewriteHeader is a policy configuration option to rewrite an HTTP header.
@@ -219,6 +222,7 @@ func NewPolicyFromProto(pb *configpb.Route) (*Policy, error) {
 		PreserveHostHeader:               pb.GetPreserveHostHeader(),
 		PassIdentityHeaders:              pb.GetPassIdentityHeaders(),
 		KubernetesServiceAccountToken:    pb.GetKubernetesServiceAccountToken(),
+		SetResponseHeaders:               pb.GetSetResponseHeaders(),
 	}
 
 	if pb.Redirect.IsSet() {
@@ -321,6 +325,7 @@ func (p *Policy) ToProto() (*configpb.Route, error) {
 		PassIdentityHeaders:              p.PassIdentityHeaders,
 		KubernetesServiceAccountToken:    p.KubernetesServiceAccountToken,
 		Policies:                         sps,
+		SetResponseHeaders:               p.SetResponseHeaders,
 	}
 	if p.Redirect != nil {
 		pb.Redirect = &configpb.RouteRedirect{

docs/reference/readme.md

@@ -1372,6 +1372,14 @@ Remove Request Headers allows you to remove given request headers. This can be u
 ```
 
 
+### Set Response Headers
+- Config File Key: `set_response_headers`
+- Type: map of `strings` key value pairs
+- Optional
+
+Set Response Headers allows you to set static values for the given response headers. These headers will take precedence over the global `set_response_headers`.
+
+
 ### Rewrite Response Headers
 - Config File Key: `rewrite_response_headers`
 - Type: `object`

docs/reference/settings.yaml

@@ -1507,6 +1507,14 @@ settings:
               - X-Email
               - X-Username
           ```
+      - name: "Set Response Headers"
+        keys: ["set_response_headers"]
+        attributes: |
+          - Config File Key: `set_response_headers`
+          - Type: map of `strings` key value pairs
+          - Optional
+        doc: |
+          Set Response Headers allows you to set static values for the given response headers. These headers will take precedence over the global `set_response_headers`.
       - name: "Rewrite Response Headers"
         keys: ["rewrite_response_headers"]
         attributes: |

pkg/grpc/config/config.proto

@@ -82,6 +82,7 @@ message Route {
 
   map<string, string> set_request_headers = 22;
   repeated string remove_request_headers = 23;
+  map<string, string> set_response_headers = 41;
   repeated RouteRewriteHeader rewrite_response_headers = 40;
 
   bool preserve_host_header = 24;