impl(bigtable): add grpc metrics exporter (#16288)

Author: scotthart

google/cloud/bigtable/BUILD.bazel

@@ -43,7 +43,10 @@ cc_library(
     srcs = google_cloud_cpp_bigtable_srcs,
     hdrs = google_cloud_cpp_bigtable_hdrs,
     local_defines = select({
-        ":metrics_enabled": ["GOOGLE_CLOUD_CPP_BIGTABLE_WITH_OTEL_METRICS"],
+        ":metrics_enabled": [
+            "GOOGLE_CLOUD_CPP_BIGTABLE_WITH_OTEL_METRICS",
+            "GOOGLE_CLOUD_CPP_BIGTABLE_WITH_GRPC_OTEL_METRICS",
+        ],
         "//conditions:default": [],
     }),
     visibility = [
@@ -65,6 +68,7 @@ cc_library(
     ] + select({
         ":metrics_enabled": [
             "//:opentelemetry",
+            "@grpc//:grpcpp_otel_plugin",
             "@opentelemetry-cpp//api",
             "@opentelemetry-cpp//sdk/src/metrics",
         ],
@@ -121,6 +125,7 @@ cc_library(
     local_defines = select({
         ":metrics_enabled": [
             "GOOGLE_CLOUD_CPP_BIGTABLE_WITH_OTEL_METRICS",
+            "GOOGLE_CLOUD_CPP_BIGTABLE_WITH_GRPC_OTEL_METRICS",
             "GOOGLE_CLOUD_CPP_BIGTABLE_QUERY_PLAN_REFRESH_ASSERT",
         ],
         "//conditions:default": ["GOOGLE_CLOUD_CPP_BIGTABLE_QUERY_PLAN_REFRESH_ASSERT"],

google/cloud/bigtable/CMakeLists.txt

@@ -190,6 +190,8 @@ add_library(
     internal/endpoint_options.h
     internal/google_bytes_traits.cc
     internal/google_bytes_traits.h
+    internal/grpc_metrics_exporter.cc
+    internal/grpc_metrics_exporter.h
     internal/logging_result_set_reader.cc
     internal/logging_result_set_reader.h
     internal/metrics.cc
@@ -285,7 +287,17 @@ target_compile_definitions(google_cloud_cpp_bigtable
                            PRIVATE GOOGLE_CLOUD_CPP_BIGTABLE_WITH_OTEL_METRICS)
 target_link_libraries(google_cloud_cpp_bigtable
                       PUBLIC google-cloud-cpp::opentelemetry)
-set(EXTRA_MODULES "google_cloud_cpp_opentelemetry" "opentelemetry_metrics")
+if (TARGET gRPC::grpcpp_otel_plugin)
+    target_compile_definitions(
+        google_cloud_cpp_bigtable
+        PRIVATE GOOGLE_CLOUD_CPP_BIGTABLE_WITH_GRPC_OTEL_METRICS)
+    target_link_libraries(google_cloud_cpp_bigtable
+                          PUBLIC gRPC::grpcpp_otel_plugin)
+    set(EXTRA_MODULES "google_cloud_cpp_opentelemetry" "grpcpp_otel_plugin"
+                      "opentelemetry_metrics")
+else ()
+    set(EXTRA_MODULES "google_cloud_cpp_opentelemetry" "opentelemetry_metrics")
+endif ()
 google_cloud_cpp_add_common_options(google_cloud_cpp_bigtable)
 target_include_directories(
     google_cloud_cpp_bigtable
@@ -460,6 +472,7 @@ if (BUILD_TESTING)
         internal/defaults_test.cc
         internal/dynamic_channel_pool_test.cc
         internal/google_bytes_traits_test.cc
+        internal/grpc_metrics_exporter_test.cc
         internal/logging_result_set_reader_test.cc
         internal/metrics_test.cc
         internal/mutate_rows_limiter_test.cc
@@ -528,6 +541,11 @@ if (BUILD_TESTING)
             target_compile_definitions(
                 ${target} PRIVATE GOOGLE_CLOUD_CPP_BIGTABLE_WITH_OTEL_METRICS)
         endif ()
+        if (TARGET gRPC::grpcpp_otel_plugin)
+            target_compile_definitions(
+                ${target}
+                PRIVATE GOOGLE_CLOUD_CPP_BIGTABLE_WITH_GRPC_OTEL_METRICS)
+        endif ()
         google_cloud_cpp_add_common_options(${target})
         add_test(NAME ${target} COMMAND ${target})
     endforeach ()

google/cloud/bigtable/bigtable_client_unit_tests.bzl

@@ -55,6 +55,7 @@ bigtable_client_unit_tests = [
     "internal/defaults_test.cc",
     "internal/dynamic_channel_pool_test.cc",
     "internal/google_bytes_traits_test.cc",
+    "internal/grpc_metrics_exporter_test.cc",
     "internal/logging_result_set_reader_test.cc",
     "internal/metrics_test.cc",
     "internal/mutate_rows_limiter_test.cc",

google/cloud/bigtable/google_cloud_cpp_bigtable.bzl

@@ -94,6 +94,7 @@ google_cloud_cpp_bigtable_hdrs = [
     "internal/dynamic_channel_pool.h",
     "internal/endpoint_options.h",
     "internal/google_bytes_traits.h",
+    "internal/grpc_metrics_exporter.h",
     "internal/logging_result_set_reader.h",
     "internal/metrics.h",
     "internal/mutate_rows_limiter.h",
@@ -206,6 +207,7 @@ google_cloud_cpp_bigtable_srcs = [
     "internal/default_row_reader.cc",
     "internal/defaults.cc",
     "internal/google_bytes_traits.cc",
+    "internal/grpc_metrics_exporter.cc",
     "internal/logging_result_set_reader.cc",
     "internal/metrics.cc",
     "internal/mutate_rows_limiter.cc",