add support for idle timeout for upstream connections (#513)

Api changes for envoyproxy/envoy#2324

Signed-off-by: Rama <rama.rao@salesforce.com>

envoy/api/v2/cds.proto

@@ -41,7 +41,7 @@ service ClusterDiscoveryService {
 // [#protodoc-title: Clusters]
 
 // Configuration for a single upstream cluster.
-// [#comment:next free field: 29]
+// [#comment:next free field: 30]
 message Cluster {
   // Supplies the name of the cluster which must be unique across all clusters.
   // The cluster name is used when emitting
@@ -184,6 +184,10 @@ message Cluster {
 
   reserved 12;
 
+  // Additional options when handling HTTP requests. These options will be applicable to both
+  // HTTP1 and HTTP2 requests.
+  core.HttpProtocolOptions common_http_protocol_options = 29;
+
   // Additional options when handling HTTP1 requests.
   core.Http1ProtocolOptions http_protocol_options = 13;
 

envoy/api/v2/core/protocol.proto

@@ -4,6 +4,7 @@ syntax = "proto3";
 
 package envoy.api.v2.core;
 
+import "google/protobuf/duration.proto";
 import "google/protobuf/wrappers.proto";
 
 import "validate/validate.proto";
@@ -17,6 +18,15 @@ option (gogoproto.equal_all) = true;
 message TcpProtocolOptions {
 }
 
+message HttpProtocolOptions {
+  // [#not-implemented-hide:]
+  // The idle timeout for upstream connection pool connections. The idle timeout is defined as the
+  // period in which there are no active requests. If not set, there is no idle timeout. When the
+  // idle timeout is reached the connection will be closed. Note that request based timeouts mean
+  // that HTTP/2 PINGs will not keep the connection alive.
+  google.protobuf.Duration idle_timeout = 1 [(gogoproto.stdduration) = true];
+}
+
 message Http1ProtocolOptions {
   // Handle HTTP requests with absolute URLs in the requests. These requests
   // are generally sent by clients to forward/explicit proxies. This allows clients to configure