ext_proc: add failure_mode_allow per route override (#40014)

Risk Level: Low
Testing: Added ext_proc unit tests
Docs Changes: N/A
Release Notes: N/A
Platform Specific Features: N/A

---------

Signed-off-by: Andres Guedez <[email protected]>
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Mirrored from https://github.com/envoyproxy/envoy @ 58fce3a7c8b585fd4bfd463497b8dc8a311c46ab

Author: update-envoy[bot]

envoy/extensions/filters/http/ext_proc/v3/ext_proc.proto

@@ -12,6 +12,7 @@ import "envoy/type/matcher/v3/string.proto";
 
 import "google/protobuf/duration.proto";
 import "google/protobuf/struct.proto";
+import "google/protobuf/wrappers.proto";
 
 import "xds/annotations/v3/status.proto";
 
@@ -417,7 +418,7 @@ message ExtProcPerRoute {
 }
 
 // Overrides that may be set on a per-route basis
-// [#next-free-field: 8]
+// [#next-free-field: 9]
 message ExtProcOverrides {
   // Set a different processing mode for this route than the default.
   ProcessingMode processing_mode = 1;
@@ -451,4 +452,9 @@ message ExtProcOverrides {
   // authorization headers (e.g. ``x-foo-bar: baz-key``) are to be injected or
   // when a route needs to partially override inherited metadata.
   repeated config.core.v3.HeaderValue grpc_initial_metadata = 7;
+
+  // If true, the filter will not fail closed if the gRPC stream is prematurely closed
+  // or could not be opened. This field is the per-route override of
+  // :ref:`failure_mode_allow <envoy_v3_api_field_extensions.filters.http.ext_proc.v3.ExternalProcessor.failure_mode_allow>`.
+  google.protobuf.BoolValue failure_mode_allow = 8;
 }