router: adding per-route upgrade config (#5034)

Allowing the HCM upgrades to be on or off by default, and adding per-route overrides to turn it off or on.

Risk Level: Medium (refactors existing code)
Testing: new unit and e2e tests
Docs Changes: proto docs
Release Notes: inline
Fixes #4921

Signed-off-by: Alyssa Wilk <alyssar@chromium.org>

Mirrored from https://github.com/envoyproxy/envoy @ d72eaaf6d1905f7d478ab80cc7163684fc271fd9

envoy/api/v2/route/route.proto

@@ -406,7 +406,7 @@ message CorsPolicy {
   google.protobuf.BoolValue enabled = 7;
 }
 
-// [#comment:next free field: 25]
+// [#comment:next free field: 26]
 message RouteAction {
   oneof cluster_specifier {
     option (validate.required) = true;
@@ -757,6 +757,22 @@ message RouteAction {
   // This can be used to prevent unexpected upstream request timeouts due to potentially long
   // time gaps between gRPC request and response in gRPC streaming mode.
   google.protobuf.Duration max_grpc_timeout = 23 [(gogoproto.stdduration) = true];
+
+  // Allows enabling and disabling upgrades on a per-route basis.
+  // This overrides any enabled/disabled upgrade filter chain specified in the
+  // HttpConnectionManager
+  // :ref:upgrade_configs`
+  // <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.upgrade_configs>`
+  // but does not affect any custom filter chain specified there.
+  message UpgradeConfig {
+    // The case-insensitive name of this upgrade, e.g. "websocket".
+    // For each upgrade type present in upgrade_configs, requests with
+    // Upgrade: [upgrade_type] will be proxied upstream.
+    string upgrade_type = 1;
+    // Determines if upgrades are available on this route. Defaults to true.
+    google.protobuf.BoolValue enabled = 2;
+  };
+  repeated UpgradeConfig upgrade_configs = 25;
 }
 
 message RedirectAction {

envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto

@@ -353,6 +353,11 @@ message HttpConnectionManager {
     // this type of upgrade. If no filters are present, the filter chain for
     // HTTP connections will be used for this upgrade type.
     repeated HttpFilter filters = 2;
+    // Determines if upgrades are enabled or disabled by default. Defaults to true.
+    // This can be overriden on a per-route basis with :ref:`cluster
+    // <envoy_api_field_route.RouteAction.upgrade_configs>` as documented in the
+    // :ref:`upgrade documentation <arch_overview_websocket>`.
+    google.protobuf.BoolValue enabled = 3;
   };
   repeated UpgradeConfig upgrade_configs = 23;