Add API for accessing per-call backend metric data in LB policies.

.gitmodules

@@ -54,3 +54,6 @@
 [submodule "third_party/upb"]
 	path = third_party/upb
 	url = https://github.com/protocolbuffers/upb.git
+[submodule "third_party/udpa"]
+	path = third_party/udpa
+	url = https://github.com/cncf/udpa.git

BUILD

@@ -1009,6 +1009,7 @@ grpc_cc_library(
     name = "grpc_client_channel",
     srcs = [
         "src/core/ext/filters/client_channel/backup_poller.cc",
+        "src/core/ext/filters/client_channel/backend_metric.cc",
         "src/core/ext/filters/client_channel/channel_connectivity.cc",
         "src/core/ext/filters/client_channel/client_channel.cc",
         "src/core/ext/filters/client_channel/client_channel_channelz.cc",
@@ -1037,6 +1038,7 @@ grpc_cc_library(
     ],
     hdrs = [
         "src/core/ext/filters/client_channel/backup_poller.h",
+        "src/core/ext/filters/client_channel/backend_metric.h",
         "src/core/ext/filters/client_channel/client_channel.h",
         "src/core/ext/filters/client_channel/client_channel_channelz.h",
         "src/core/ext/filters/client_channel/client_channel_factory.h",
@@ -1066,6 +1068,7 @@ grpc_cc_library(
     ],
     language = "c++",
     deps = [
+        "envoy_orca_upb",
         "gpr_base",
         "grpc_base",
         "grpc_client_authority_filter",
@@ -2278,6 +2281,7 @@ grpc_cc_library(
         "src/core/ext/upb-generated/envoy/api/v2/auth/cert.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/cds.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.c",
+        "src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/discovery.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/eds.upb.c",
@@ -2290,6 +2294,7 @@ grpc_cc_library(
         "src/core/ext/upb-generated/envoy/api/v2/auth/cert.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/cds.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.h",
+        "src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/discovery.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/eds.upb.h",
@@ -2318,6 +2323,7 @@ grpc_cc_library(
         "src/core/ext/upb-generated/envoy/api/v2/core/config_source.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/core/grpc_service.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.c",
+        "src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.c",
     ],
     hdrs = [
@@ -2326,6 +2332,7 @@ grpc_cc_library(
         "src/core/ext/upb-generated/envoy/api/v2/core/config_source.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/grpc_service.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.h",
+        "src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.h",
     ],
     external_deps = [
@@ -2378,6 +2385,29 @@ grpc_cc_library(
     ],
 )
 
+# Once upb code-gen issue is resolved, replace envoy_orca_upb with this.
+# grpc_upb_proto_library(
+#     name = "envoy_orca_upb",
+#     deps = ["@envoy_api//udpa/data/orca/v1:orca_load_report"]
+# )
+
+grpc_cc_library(
+    name = "envoy_orca_upb",
+    srcs = [
+        "src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c",
+    ],
+    hdrs = [
+        "src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.h",
+    ],
+    external_deps = [
+        "upb_lib",
+    ],
+    language = "c++",
+    deps = [
+        ":proto_gen_validate_upb",
+    ],
+)
+
 # Once upb code-gen issue is resolved, replace grpc_health_upb with this.
 # grpc_upb_proto_library(
 #     name = "grpc_health_upb",

BUILD.gn

@@ -208,6 +208,8 @@ config("grpc_config") {
         "include/grpc/status.h",
         "include/grpc/support/workaround_list.h",
         "src/core/ext/filters/census/grpc_context.cc",
+        "src/core/ext/filters/client_channel/backend_metric.cc",
+        "src/core/ext/filters/client_channel/backend_metric.h",
         "src/core/ext/filters/client_channel/backup_poller.cc",
         "src/core/ext/filters/client_channel/backup_poller.h",
         "src/core/ext/filters/client_channel/channel_connectivity.cc",
@@ -388,6 +390,8 @@ config("grpc_config") {
         "src/core/ext/upb-generated/envoy/api/v2/cds.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.h",
+        "src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.c",
+        "src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/address.upb.c",
@@ -400,6 +404,8 @@ config("grpc_config") {
         "src/core/ext/upb-generated/envoy/api/v2/core/grpc_service.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.h",
+        "src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.c",
+        "src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.c",
         "src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.h",
         "src/core/ext/upb-generated/envoy/api/v2/discovery.upb.c",
@@ -450,6 +456,8 @@ config("grpc_config") {
         "src/core/ext/upb-generated/src/proto/grpc/health/v1/health.upb.h",
         "src/core/ext/upb-generated/src/proto/grpc/lb/v1/load_balancer.upb.c",
         "src/core/ext/upb-generated/src/proto/grpc/lb/v1/load_balancer.upb.h",
+        "src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c",
+        "src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.h",
         "src/core/ext/upb-generated/validate/validate.upb.c",
         "src/core/ext/upb-generated/validate/validate.upb.h",
         "src/core/lib/avl/avl.cc",

CMakeLists.txt

@@ -1266,6 +1266,7 @@ add_library(grpc
   src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc
   src/core/ext/transport/chttp2/client/authority.cc
   src/core/ext/transport/chttp2/client/chttp2_connector.cc
+  src/core/ext/filters/client_channel/backend_metric.cc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
@@ -1294,6 +1295,19 @@ add_library(grpc
   src/core/ext/filters/client_channel/subchannel_pool_interface.cc
   src/core/ext/filters/deadline/deadline_filter.cc
   src/core/ext/upb-generated/src/proto/grpc/health/v1/health.upb.c
+  src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c
+  src/core/ext/upb-generated/gogoproto/gogo.upb.c
+  src/core/ext/upb-generated/validate/validate.upb.c
+  src/core/ext/upb-generated/google/api/annotations.upb.c
+  src/core/ext/upb-generated/google/api/http.upb.c
+  src/core/ext/upb-generated/google/protobuf/any.upb.c
+  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
+  src/core/ext/upb-generated/google/protobuf/duration.upb.c
+  src/core/ext/upb-generated/google/protobuf/empty.upb.c
+  src/core/ext/upb-generated/google/protobuf/struct.upb.c
+  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
+  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
+  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/tsi/fake_transport_security.cc
   src/core/tsi/local_transport_security.cc
   src/core/tsi/ssl/session_cache/ssl_session_boringssl.cc
@@ -1313,16 +1327,6 @@ add_library(grpc
   src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc
   src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc
   src/core/ext/upb-generated/src/proto/grpc/lb/v1/load_balancer.upb.c
-  src/core/ext/upb-generated/google/api/annotations.upb.c
-  src/core/ext/upb-generated/google/api/http.upb.c
-  src/core/ext/upb-generated/google/protobuf/any.upb.c
-  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
-  src/core/ext/upb-generated/google/protobuf/duration.upb.c
-  src/core/ext/upb-generated/google/protobuf/empty.upb.c
-  src/core/ext/upb-generated/google/protobuf/struct.upb.c
-  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
-  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
-  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
   src/core/ext/filters/client_channel/lb_policy/xds/xds.cc
   src/core/ext/filters/client_channel/lb_policy/xds/xds_channel_secure.cc
@@ -1331,6 +1335,7 @@ add_library(grpc
   src/core/ext/upb-generated/envoy/api/v2/auth/cert.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cds.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.c
+  src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.c
   src/core/ext/upb-generated/envoy/api/v2/discovery.upb.c
   src/core/ext/upb-generated/envoy/api/v2/eds.upb.c
@@ -1343,11 +1348,10 @@ add_library(grpc
   src/core/ext/upb-generated/envoy/api/v2/core/config_source.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/grpc_service.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.c
+  src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.c
   src/core/ext/upb-generated/envoy/type/percent.upb.c
   src/core/ext/upb-generated/envoy/type/range.upb.c
-  src/core/ext/upb-generated/gogoproto/gogo.upb.c
-  src/core/ext/upb-generated/validate/validate.upb.c
   src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
   src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -1667,6 +1671,7 @@ add_library(grpc_cronet
   src/core/ext/filters/http/http_filters_plugin.cc
   src/core/ext/filters/http/message_compress/message_compress_filter.cc
   src/core/ext/filters/http/server/http_server_filter.cc
+  src/core/ext/filters/client_channel/backend_metric.cc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
@@ -1701,6 +1706,19 @@ add_library(grpc_cronet
   third_party/upb/upb/port.c
   third_party/upb/upb/table.c
   third_party/upb/upb/upb.c
+  src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c
+  src/core/ext/upb-generated/gogoproto/gogo.upb.c
+  src/core/ext/upb-generated/validate/validate.upb.c
+  src/core/ext/upb-generated/google/api/annotations.upb.c
+  src/core/ext/upb-generated/google/api/http.upb.c
+  src/core/ext/upb-generated/google/protobuf/any.upb.c
+  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
+  src/core/ext/upb-generated/google/protobuf/duration.upb.c
+  src/core/ext/upb-generated/google/protobuf/empty.upb.c
+  src/core/ext/upb-generated/google/protobuf/struct.upb.c
+  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
+  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
+  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/lib/http/httpcli_security_connector.cc
   src/core/lib/security/context/security_context.cc
   src/core/lib/security/credentials/alts/alts_credentials.cc
@@ -2059,6 +2077,7 @@ add_library(grpc_test_util
   src/core/lib/transport/transport_op_string.cc
   src/core/lib/uri/uri_parser.cc
   src/core/lib/debug/trace.cc
+  src/core/ext/filters/client_channel/backend_metric.cc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
@@ -2093,6 +2112,19 @@ add_library(grpc_test_util
   third_party/upb/upb/port.c
   third_party/upb/upb/table.c
   third_party/upb/upb/upb.c
+  src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c
+  src/core/ext/upb-generated/gogoproto/gogo.upb.c
+  src/core/ext/upb-generated/validate/validate.upb.c
+  src/core/ext/upb-generated/google/api/annotations.upb.c
+  src/core/ext/upb-generated/google/api/http.upb.c
+  src/core/ext/upb-generated/google/protobuf/any.upb.c
+  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
+  src/core/ext/upb-generated/google/protobuf/duration.upb.c
+  src/core/ext/upb-generated/google/protobuf/empty.upb.c
+  src/core/ext/upb-generated/google/protobuf/struct.upb.c
+  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
+  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
+  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/ext/transport/chttp2/transport/bin_decoder.cc
   src/core/ext/transport/chttp2/transport/bin_encoder.cc
   src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
@@ -2399,6 +2431,7 @@ add_library(grpc_test_util_unsecure
   src/core/lib/transport/transport_op_string.cc
   src/core/lib/uri/uri_parser.cc
   src/core/lib/debug/trace.cc
+  src/core/ext/filters/client_channel/backend_metric.cc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
@@ -2433,6 +2466,19 @@ add_library(grpc_test_util_unsecure
   third_party/upb/upb/port.c
   third_party/upb/upb/table.c
   third_party/upb/upb/upb.c
+  src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c
+  src/core/ext/upb-generated/gogoproto/gogo.upb.c
+  src/core/ext/upb-generated/validate/validate.upb.c
+  src/core/ext/upb-generated/google/api/annotations.upb.c
+  src/core/ext/upb-generated/google/api/http.upb.c
+  src/core/ext/upb-generated/google/protobuf/any.upb.c
+  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
+  src/core/ext/upb-generated/google/protobuf/duration.upb.c
+  src/core/ext/upb-generated/google/protobuf/empty.upb.c
+  src/core/ext/upb-generated/google/protobuf/struct.upb.c
+  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
+  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
+  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/ext/transport/chttp2/transport/bin_decoder.cc
   src/core/ext/transport/chttp2/transport/bin_encoder.cc
   src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
@@ -2750,6 +2796,7 @@ add_library(grpc_unsecure
   src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc
   src/core/ext/transport/chttp2/client/authority.cc
   src/core/ext/transport/chttp2/client/chttp2_connector.cc
+  src/core/ext/filters/client_channel/backend_metric.cc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
@@ -2784,6 +2831,19 @@ add_library(grpc_unsecure
   third_party/upb/upb/port.c
   third_party/upb/upb/table.c
   third_party/upb/upb/upb.c
+  src/core/ext/upb-generated/udpa/data/orca/v1/orca_load_report.upb.c
+  src/core/ext/upb-generated/gogoproto/gogo.upb.c
+  src/core/ext/upb-generated/validate/validate.upb.c
+  src/core/ext/upb-generated/google/api/annotations.upb.c
+  src/core/ext/upb-generated/google/api/http.upb.c
+  src/core/ext/upb-generated/google/protobuf/any.upb.c
+  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
+  src/core/ext/upb-generated/google/protobuf/duration.upb.c
+  src/core/ext/upb-generated/google/protobuf/empty.upb.c
+  src/core/ext/upb-generated/google/protobuf/struct.upb.c
+  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
+  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
+  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/ext/transport/inproc/inproc_plugin.cc
   src/core/ext/transport/inproc/inproc_transport.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -2807,23 +2867,14 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc
   src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc
   src/core/ext/upb-generated/src/proto/grpc/lb/v1/load_balancer.upb.c
-  src/core/ext/upb-generated/google/api/annotations.upb.c
-  src/core/ext/upb-generated/google/api/http.upb.c
-  src/core/ext/upb-generated/google/protobuf/any.upb.c
-  src/core/ext/upb-generated/google/protobuf/descriptor.upb.c
-  src/core/ext/upb-generated/google/protobuf/duration.upb.c
-  src/core/ext/upb-generated/google/protobuf/empty.upb.c
-  src/core/ext/upb-generated/google/protobuf/struct.upb.c
-  src/core/ext/upb-generated/google/protobuf/timestamp.upb.c
-  src/core/ext/upb-generated/google/protobuf/wrappers.upb.c
-  src/core/ext/upb-generated/google/rpc/status.upb.c
   src/core/ext/filters/client_channel/lb_policy/xds/xds.cc
   src/core/ext/filters/client_channel/lb_policy/xds/xds_channel.cc
   src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.cc
   src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.cc
   src/core/ext/upb-generated/envoy/api/v2/auth/cert.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cds.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cluster/circuit_breaker.upb.c
+  src/core/ext/upb-generated/envoy/api/v2/cluster/filter.upb.c
   src/core/ext/upb-generated/envoy/api/v2/cluster/outlier_detection.upb.c
   src/core/ext/upb-generated/envoy/api/v2/discovery.upb.c
   src/core/ext/upb-generated/envoy/api/v2/eds.upb.c
@@ -2836,11 +2887,10 @@ add_library(grpc_unsecure
   src/core/ext/upb-generated/envoy/api/v2/core/config_source.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/grpc_service.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/health_check.upb.c
+  src/core/ext/upb-generated/envoy/api/v2/core/http_uri.upb.c
   src/core/ext/upb-generated/envoy/api/v2/core/protocol.upb.c
   src/core/ext/upb-generated/envoy/type/percent.upb.c
   src/core/ext/upb-generated/envoy/type/range.upb.c
-  src/core/ext/upb-generated/gogoproto/gogo.upb.c
-  src/core/ext/upb-generated/validate/validate.upb.c
   src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
   src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
   src/core/ext/filters/census/grpc_context.cc
@@ -13128,11 +13178,18 @@ endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
 add_executable(client_lb_end2end_test
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/lb/v2/orca_load_report_for_test.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/lb/v2/orca_load_report_for_test.grpc.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/lb/v2/orca_load_report_for_test.pb.h
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/lb/v2/orca_load_report_for_test.grpc.pb.h
   test/cpp/end2end/client_lb_end2end_test.cc
   third_party/googletest/googletest/src/gtest-all.cc
   third_party/googletest/googlemock/src/gmock-all.cc
 )
 
+protobuf_generate_grpc_cpp(
+  src/proto/grpc/lb/v2/orca_load_report_for_test.proto
+)
 
 target_include_directories(client_lb_end2end_test
   PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}