router: Add support for per-route configurable maximum number of internal redirect hops (#9574)

Add support for per-route configurable maximum number of internal redirect hops

Risk Level: Medium
Testing: Unit and integration tests added / modified
Docs Changes: Described the new field in intro/arch_overview/http/http_connection_management.rst
Release Notes: Added

Fixes #9144

Signed-off-by: Peng Gao <pengg@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 1f208984f1eb6253c3f2ee49139831f6766b673e

envoy/api/v2/route/route_components.proto

@@ -518,7 +518,7 @@ message CorsPolicy {
   core.RuntimeFractionalPercent shadow_enabled = 10;
 }
 
-// [#next-free-field: 31]
+// [#next-free-field: 32]
 message RouteAction {
   enum ClusterNotFoundResponseCode {
     // HTTP status code - 503 Service Unavailable.
@@ -875,6 +875,22 @@ message RouteAction {
 
   InternalRedirectAction internal_redirect_action = 26;
 
+  // An internal redirect is handled, iff the number of previous internal redirects that a
+  // downstream request has encountered is lower than this value, and
+  // :ref:`internal_redirect_action <envoy_api_field_route.RouteAction.internal_redirect_action>`
+  // is set to :ref:`HANDLE_INTERNAL_REDIRECT
+  // <envoy_api_enum_value_route.RouteAction.InternalRedirectAction.HANDLE_INTERNAL_REDIRECT>`
+  // In the case where a downstream request is bounced among multiple routes by internal redirect,
+  // the first route that hits this threshold, or has
+  // :ref:`internal_redirect_action <envoy_api_field_route.RouteAction.internal_redirect_action>`
+  // set to
+  // :ref:`PASS_THROUGH_INTERNAL_REDIRECT
+  // <envoy_api_enum_value_route.RouteAction.InternalRedirectAction.PASS_THROUGH_INTERNAL_REDIRECT>`
+  // will pass the redirect back to downstream.
+  //
+  // If not specified, at most one redirect will be followed.
+  google.protobuf.UInt32Value max_internal_redirects = 31;
+
   // Indicates that the route has a hedge policy. Note that if this is set,
   // it'll take precedence over the virtual host level hedge policy entirely
   // (e.g.: policies are not merged, most internal one becomes the enforced policy).

envoy/config/route/v3alpha/route_components.proto

@@ -487,7 +487,7 @@ message CorsPolicy {
   core.v3alpha.RuntimeFractionalPercent shadow_enabled = 10;
 }
 
-// [#next-free-field: 31]
+// [#next-free-field: 32]
 message RouteAction {
   option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.route.RouteAction";
 
@@ -853,6 +853,23 @@ message RouteAction {
 
   InternalRedirectAction internal_redirect_action = 26;
 
+  // An internal redirect is handled, iff the number of previous internal redirects that a
+  // downstream request has encountered is lower than this value, and
+  // :ref:`internal_redirect_action
+  // <envoy_api_field_config.route.v3alpha.RouteAction.internal_redirect_action>` is set to
+  // :ref:`HANDLE_INTERNAL_REDIRECT
+  // <envoy_api_enum_value_config.route.v3alpha.RouteAction.InternalRedirectAction.HANDLE_INTERNAL_REDIRECT>`
+  // In the case where a downstream request is bounced among multiple routes by internal redirect,
+  // the first route that hits this threshold, or has
+  // :ref:`internal_redirect_action
+  // <envoy_api_field_config.route.v3alpha.RouteAction.internal_redirect_action>` set to
+  // :ref:`PASS_THROUGH_INTERNAL_REDIRECT
+  // <envoy_api_enum_value_config.route.v3alpha.RouteAction.InternalRedirectAction.PASS_THROUGH_INTERNAL_REDIRECT>`
+  // will pass the redirect back to downstream.
+  //
+  // If not specified, at most one redirect will be followed.
+  google.protobuf.UInt32Value max_internal_redirects = 31;
+
   // Indicates that the route has a hedge policy. Note that if this is set,
   // it'll take precedence over the virtual host level hedge policy entirely
   // (e.g.: policies are not merged, most internal one becomes the enforced policy).