lds: Add HTTP API listener.

api/envoy/api/v2/BUILD

@@ -27,6 +27,7 @@ api_proto_package(
         "//envoy/api/v2/listener:pkg",
         "//envoy/api/v2/ratelimit:pkg",
         "//envoy/api/v2/route:pkg",
+        "//envoy/config/api_listener/v2:pkg",
         "//envoy/type",
     ],
 )
@@ -86,6 +87,7 @@ api_proto_library_internal(
         "//envoy/api/v2/core:base",
         "//envoy/api/v2/listener",
         "//envoy/api/v2/listener:udp_listener_config",
+        "//envoy/config/api_listener/v2:api_listener",
     ],
 )
 

api/envoy/api/v2/lds.proto

@@ -13,6 +13,7 @@ import "envoy/api/v2/core/base.proto";
 import "envoy/api/v2/discovery.proto";
 import "envoy/api/v2/listener/listener.proto";
 import "envoy/api/v2/listener/udp_listener_config.proto";
+import "envoy/config/api_listener/v2/api_listener.proto";
 
 import "google/api/annotations.proto";
 import "google/protobuf/duration.proto";
@@ -45,7 +46,7 @@ service ListenerDiscoveryService {
   }
 }
 
-// [#comment:next free field: 19]
+// [#comment:next free field: 20]
 message Listener {
   // The unique name by which this listener is known. If no name is provided,
   // Envoy will allocate an internal UUID for the listener. If the listener is to be dynamically
@@ -203,4 +204,17 @@ message Listener {
   // <envoy_api_field_listener.UdpListenerConfig.udp_listener_name>` = "raw_udp_listener" for
   // creating a packet-oriented UDP listener. If not present, treat it as "raw_udp_listener".
   listener.UdpListenerConfig udp_listener_config = 18;
+
+  // [#not-implemented-hide:]
+  // Used to represent an API listener, which is used in non-proxy clients. The type of API
+  // exposed to the non-proxy application depends on the type of API listener.
+  // When this field is set, no other field except for :ref:`name<envoy_api_field_Listener.name>`
+  // should be set.
+  // [#next-major-version: In the v3 API, instead of this messy approach where the socket
+  // listener fields are directly in the top-level Listener message and the API listener types
+  // are in the ApiListener message, the socket listener messages should be in their own message,
+  // and the top-level Listener should essentially be a oneof that selects between the
+  // socket listener and the various types of API listener. That way, a given Listener message
+  // can structurally only contain the fields of the relevant type.]
+  envoy.config.listener.v2.ApiListener api_listener = 19;
 }

api/envoy/config/api_listener/v2/BUILD

@@ -0,0 +1,18 @@
+load("@envoy_api//bazel:api_build_system.bzl", "api_proto_library_internal", "api_proto_package")
+
+licenses(["notice"])  # Apache 2
+
+package_group(
+    name = "friends",
+    packages = [
+        "//envoy/api/v2",
+    ],
+)
+
+api_proto_package()
+
+api_proto_library_internal(
+    name = "api_listener",
+    srcs = ["api_listener.proto"],
+    visibility = [":friends"],
+)

api/envoy/config/api_listener/v2/api_listener.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package envoy.config.listener.v2;
+
+option java_outer_classname = "ApiListenerProto";
+option java_multiple_files = true;
+option java_package = "io.envoyproxy.envoy.config.api_listener.v2";
+
+import "google/protobuf/any.proto";
+
+// [#not-implemented-hide:]
+// Describes a type of API listener, which is used in non-proxy clients. The type of API
+// exposed to the non-proxy application depends on the type of API listener.
+message ApiListener {
+  // The type in this field determines the type of API listener. At present, the following
+  // types are supported:
+  //   envoy.config.filter.network.http_connection_manager.v2.HttpConnectionManager (HTTP)
+  // [#next-major-version: In the v3 API, replace this Any field with a oneof containing the
+  // specific config message for each type of API listener. We could not do this in v2 because
+  // it would have caused circular dependencies for go protos: lds.proto depends on this file,
+  // and http_connection_manager.proto depends on rds.proto, which is in the same directory as
+  // lds.proto, so lds.proto cannot depend on this file.]
+  google.protobuf.Any api_listener = 1;
+}