Pre-work for centralized trace flags

PiperOrigin-RevId: 635971487

BUILD

@@ -19,6 +19,7 @@ load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
 load(
     "//bazel:grpc_build_system.bzl",
     "grpc_cc_library",
+    "grpc_filegroup",
     "grpc_generate_one_off_targets",
     "grpc_upb_proto_library",
     "grpc_upb_proto_reflection_library",
@@ -3037,6 +3038,11 @@ grpc_cc_library(
     ],
 )
 
+grpc_filegroup(
+    name = "trace_flag_files",
+    srcs = ["//src/core:lib/debug/trace_flags.yaml"],
+)
+
 grpc_cc_library(
     name = "load_config",
     srcs = [

bazel/grpc_build_system.bzl

@@ -735,6 +735,13 @@ def grpc_package(name, visibility = "private", features = []):
             features = features,
         )
 
+def grpc_filegroup(name, srcs, **kwargs):
+    native.filegroup(
+        name = name,
+        srcs = srcs,
+        **kwargs
+    )
+
 def grpc_objc_library(
         name,
         srcs = [],

src/core/lib/debug/trace_flags.cc

@@ -0,0 +1,13 @@
+// Copyright 2024 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.

src/core/lib/debug/trace_flags.h

@@ -0,0 +1,18 @@
+// Copyright 2024 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H
+#define GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H
+
+#endif  // GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H

tools/codegen/core/templates/trace_flags.cc.mako

@@ -0,0 +1,56 @@
+// Copyright 2024 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//
+// Automatically generated by tools/codegen/core/gen_trace_flags.py
+//
+
+#include "${absl_prefix}absl/container/flat_hash_map.h"
+
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gprpp/no_destruct.h"
+
+namespace grpc_core {
+
+% for flag, settings in trace_flags.items():
+% if "debug_only" in settings and settings["debug_only"]:
+DebugOnlyTraceFlag ${flag}_trace(${str(settings["default"]).lower()}, "${flag}");
+% endif
+% endfor
+% for flag, settings in trace_flags.items():
+% if "debug_only" not in settings or not settings["debug_only"]:
+TraceFlag ${flag}_trace(${str(settings["default"]).lower()}, "${flag}");
+% endif
+% endfor
+
+const absl::flat_hash_map<std::string, TraceFlag*>& GetAllTraceFlags() {
+  static const NoDestruct<absl::flat_hash_map<std::string, TraceFlag*>>
+      all(absl::flat_hash_map<std::string, TraceFlag*>({
+% for flag, settings in trace_flags.items():
+% if "debug_only" not in settings or not settings["debug_only"]:
+    {"${flag}", &${flag}_trace},
+% endif
+% endfor
+#ifndef NDEBUG
+% for flag, settings in trace_flags.items():
+% if "debug_only" in settings and settings["debug_only"]:
+    {"${flag}", &${flag}_trace},
+% endif
+% endfor
+#endif
+  }));
+  return *all;
+}
+
+}  // namespace grpc_core

tools/codegen/core/templates/trace_flags.h.mako

@@ -0,0 +1,40 @@
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//
+// Automatically generated by tools/codegen/core/gen_trace_flags.py
+//
+
+#ifndef GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H
+#define GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H
+
+#include "src/core/lib/debug/trace_impl.h"
+
+
+namespace grpc_core {
+
+% for flag, settings in trace_flags.items():
+% if "debug_only" in settings and settings["debug_only"]:
+extern DebugOnlyTraceFlag ${flag}_trace;
+% endif
+% endfor
+% for flag, settings in trace_flags.items():
+% if not "debug_only" in settings or not settings["debug_only"]:
+extern TraceFlag ${flag}_trace;
+% endif
+% endfor
+
+}  // namespace grpc_core
+
+#endif  // GRPC_SRC_CORE_LIB_DEBUG_TRACE_FLAGS_H

tools/codegen/core/templates/trace_flags.md.mako

@@ -0,0 +1,48 @@
+<!---
+Automatically generated by tools/codegen/core/gen_trace_flags.py
+--->
+
+gRPC Trace Flags
+----------------
+
+The `GRPC_TRACE` environment variable supports a comma-separated list of tracer
+names or glob patterns that provide additional insight into how gRPC C core is
+processing requests via debug logs. Available tracers include:
+
+% for flag, settings in trace_flags.items():
+% if "internal" in settings and settings["internal"]:
+<% continue %>
+% endif
+% if "debug_only" not in settings or not settings["debug_only"]:
+% if settings["description"]:
+  - ${flag} - ${settings["description"]}
+% else:
+  - ${flag}
+% endif
+% endif
+% endfor
+
+The following tracers will only run in binaries built in DEBUG mode. This is
+accomplished by invoking `bazel build --config=dbg <target>`
+% for flag, settings in trace_flags.items():
+% if "internal" in settings and settings["internal"]:
+<% continue %>
+% endif
+% if "debug_only" in settings and settings["debug_only"]:
+% if settings["description"]:
+  - ${flag} - ${settings["description"]}
+% else:
+  - ${flag}
+% endif
+% endif
+% endfor
+
+Glob patterns and special cases:
+  - `*` can be used to turn all traces on.
+  - Individual traces can be disabled by prefixing them with `-`.
+  - `*refcount*` will turn on all of the tracers for refcount debugging.
+  - if `list_tracers` is present, then all of the available tracers will be
+    printed when the program starts up.
+
+Example:
+export GRPC_TRACE=*,-pending_tags