Add grpc_rs for exporting internal APIs

BUILD

@@ -534,6 +534,25 @@ GRPCXX_PUBLIC_HDRS = [
     "include/grpcpp/impl/codegen/sync.h",
 ]
 
+grpc_cc_library(
+    name = "grpc_rs",
+    srcs = [
+        "//:src/rs/stats.cc",
+    ],
+    language = "c++",
+    public_hdrs = [
+        "include/grpcrs/stats.h",
+    ],
+    tags = [
+        "nofixdeps",
+    ],
+    visibility = ["@grpc:public"],
+    deps = [
+        "stats",
+        "//src/core:slice",
+    ],
+)
+
 grpc_cc_library(
     name = "grpc_unsecure",
     srcs = [
@@ -560,6 +579,7 @@ grpc_cc_library(
         "grpc_client_channel",
         "grpc_common",
         "grpc_http_filters",
+        "grpc_rs",
         "grpc_security_base",
         "grpc_trace",
         "http_connect_handshaker",
@@ -636,6 +656,7 @@ grpc_cc_library(
         "grpc_http_filters",
         "grpc_jwt_credentials",
         "grpc_public_hdrs",
+        "grpc_rs",
         "grpc_security_base",
         "grpc_trace",
         "http_connect_handshaker",

include/grpcrs/stats.h

@@ -0,0 +1,81 @@
+// Copyright 2023 TiKV Project Authors. Licensed under Apache-2.0.
+
+#ifndef GRPC_RS_STATS_H
+#define GRPC_RS_STATS_H
+
+#include <grpc/support/port_platform.h>
+#include <grpc/slice.h>
+
+#ifndef GRPCRSAPI
+#define GRPCRSAPI GPRAPI
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** gRPC stats.
+    See: grpc/src/core/lib/debug/stats_data.yaml */
+typedef struct grpcrs_stats grpcrs_stats;
+
+enum grpcrs_stats_counter {
+  ClientCallsCreated,
+  ServerCallsCreated,
+  ClientChannelsCreated,
+  ClientSubchannelsCreated,
+  ServerChannelsCreated,
+  InsecureConnectionsCreated,
+  SyscallWrite,
+  SyscallRead,
+  TcpReadAlloc8k,
+  TcpReadAlloc64k,
+  Http2SettingsWrites,
+  Http2PingsSent,
+  Http2WritesBegun,
+  Http2TransportStalls,
+  Http2StreamStalls,
+  CqPluckCreates,
+  CqNextCreates,
+  CqCallbackCreates,
+  COUNTER_COUNT
+};
+
+enum grpcrs_stats_histogram {
+  CallInitialSize,
+  TcpWriteSize,
+  TcpWriteIovSize,
+  TcpReadSize,
+  TcpReadOffer,
+  TcpReadOfferIovSize,
+  Http2SendMessageSize,
+  Http2MetadataSize,
+  HISTOGRAM_COUNT
+};
+
+GRPCRSAPI grpcrs_stats* grpcrs_stats_collect();
+
+GRPCRSAPI void grpcrs_stats_free(grpcrs_stats* stats);
+
+GRPCRSAPI uint64_t grpcrs_stats_get_counter(
+    const grpcrs_stats* stats, grpcrs_stats_counter which);
+
+GRPCRSAPI grpc_slice grpcrs_stats_counter_name(grpcrs_stats_counter which);
+
+GRPCRSAPI grpc_slice grpcrs_stats_counter_doc(grpcrs_stats_counter which);
+
+GRPCRSAPI double grpcrs_stats_get_histogram_percentile(
+    const grpcrs_stats* stats, grpcrs_stats_histogram which,
+    double percentile);
+
+GRPCRSAPI double grpcrs_stats_get_histogram_count(
+    const grpcrs_stats* stats, grpcrs_stats_histogram which);
+
+GRPCRSAPI grpc_slice grpcrs_stats_histogram_name(grpcrs_stats_histogram which);
+
+GRPCRSAPI grpc_slice grpcrs_stats_histogram_doc(grpcrs_stats_histogram which);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_RS_STATS_H */

src/rs/stats.cc

@@ -0,0 +1,74 @@
+// Copyright 2023 TiKV Project Authors. Licensed under Apache-2.0.
+
+#include <include/grpcrs/stats.h>
+
+#include "src/core/lib/debug/stats.h"
+#include "src/core/lib/debug/stats_data.h"
+
+// Just make sure they have the same number of counters.
+static_assert(static_cast<int>(grpcrs_stats_counter::COUNTER_COUNT) ==
+                  static_cast<int>(grpc_core::GlobalStats::Counter::COUNT),
+              "Counter count must be the same");
+
+// Just make sure they have the same number of histograms.
+static_assert(static_cast<int>(grpcrs_stats_histogram::HISTOGRAM_COUNT) ==
+                  static_cast<int>(grpc_core::GlobalStats::Histogram::COUNT),
+              "Histogram count must be the same");
+
+grpcrs_stats* grpcrs_stats_collect() {
+  return (grpcrs_stats*)grpc_core::global_stats().Collect().release();
+}
+
+void grpcrs_stats_free(grpcrs_stats* stats) {
+  auto s = (grpc_core::GlobalStats*)stats;
+  delete s;
+}
+
+uint64_t grpcrs_stats_get_counter(
+    const grpcrs_stats* stats, grpcrs_stats_counter which) {
+  auto s = (const grpc_core::GlobalStats*)stats;
+  return s->counters[which];
+}
+
+grpc_slice
+grpcrs_stats_counter_name(grpcrs_stats_counter which) {
+  auto name = grpc_core::GlobalStats::counter_name[which];
+  auto slice = grpc_slice_from_static_buffer(name.data(), name.size());
+  return slice;
+}
+
+grpc_slice
+grpcrs_stats_counter_doc(grpcrs_stats_counter which) {
+  auto doc = grpc_core::GlobalStats::counter_doc[which];
+  auto slice = grpc_slice_from_static_buffer(doc.data(), doc.size());
+  return slice;
+}
+
+double grpcrs_stats_get_histogram_percentile(
+    const grpcrs_stats* stats, grpcrs_stats_histogram which,
+    double percentile) {
+  auto s = (const grpc_core::GlobalStats*)stats;
+  return s->histogram(static_cast<grpc_core::GlobalStats::Histogram>(which))
+      .Percentile(percentile);
+}
+
+double grpcrs_stats_get_histogram_count(
+    const grpcrs_stats* stats, grpcrs_stats_histogram which) {
+  auto s = (const grpc_core::GlobalStats*)stats;
+  return s->histogram(static_cast<grpc_core::GlobalStats::Histogram>(which))
+      .Count();
+}
+
+grpc_slice
+grpcrs_stats_histogram_name(grpcrs_stats_histogram which) {
+  auto name = grpc_core::GlobalStats::histogram_name[which];
+  auto slice = grpc_slice_from_static_buffer(name.data(), name.size());
+  return slice;
+}
+
+grpc_slice
+grpcrs_stats_histogram_doc(grpcrs_stats_histogram which) {
+  auto doc = grpc_core::GlobalStats::histogram_doc[which];
+  auto slice = grpc_slice_from_static_buffer(doc.data(), doc.size());
+  return slice;
+}