From 39f3bd7ebb53cb7106ee9550b68b2d0299fe11ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20H=C3=A4ber?= <andy@andyandy.info>
Date: Sun, 18 Oct 2020 23:47:14 +0200
Subject: [PATCH] Build gRPC with CMake for OLTP exporter
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Uses FetchContent to fetch gRPC. Adds the gRPC plugin to the protoc
command to generate gRPC files. Finally, adds the path for the generated
gRPC and protobuf files to the target include directory property.

Signed-off-by: Andreas Häber <andy@andyandy.info>
---
 exporters/otlp/CMakeLists.txt                 |  3 +
 .../opentelemetry-proto/Protobuf.cmake        | 82 ++++++++++++-------
 2 files changed, 54 insertions(+), 31 deletions(-)

diff --git a/exporters/otlp/CMakeLists.txt b/exporters/otlp/CMakeLists.txt
index 27ee7de956..3589c28b5c 100644
--- a/exporters/otlp/CMakeLists.txt
+++ b/exporters/otlp/CMakeLists.txt
@@ -1,6 +1,9 @@
 include_directories(include)
 
 add_library(opentelemetry_exporter_otprotocol src/recordable.cc)
+target_include_directories(
+  opentelemetry_exporter_otprotocol
+  PUBLIC $<TARGET_PROPERTY:opentelemetry_proto,INTERFACE_INCLUDE_DIRECTORIES>)
 target_link_libraries(opentelemetry_exporter_otprotocol
                       $<TARGET_OBJECTS:opentelemetry_proto>)
 
diff --git a/third_party/opentelemetry-proto/Protobuf.cmake b/third_party/opentelemetry-proto/Protobuf.cmake
index 50a174f1fc..95a3fae81c 100644
--- a/third_party/opentelemetry-proto/Protobuf.cmake
+++ b/third_party/opentelemetry-proto/Protobuf.cmake
@@ -1,48 +1,68 @@
+include(FetchContent)
+FetchContent_Declare(
+  gRPC
+  GIT_REPOSITORY https://github.com/grpc/grpc
+  GIT_TAG v1.32.0)
+FetchContent_MakeAvailable(gRPC)
+
 set(PROTO_PATH "${CMAKE_SOURCE_DIR}/third_party/opentelemetry-proto")
 
 set(COMMON_PROTO "${PROTO_PATH}/opentelemetry/proto/common/v1/common.proto")
-set(RESOURCE_PROTO "${PROTO_PATH}/opentelemetry/proto/resource/v1/resource.proto")
+set(RESOURCE_PROTO
+    "${PROTO_PATH}/opentelemetry/proto/resource/v1/resource.proto")
 set(TRACE_PROTO "${PROTO_PATH}/opentelemetry/proto/trace/v1/trace.proto")
 
-set(GENERATED_PROTOBUF_PATH "${CMAKE_BINARY_DIR}/generated/third_party/opentelemetry-proto")
+set(GENERATED_PROTOBUF_PATH
+    "${CMAKE_BINARY_DIR}/generated/third_party/opentelemetry-proto")
 
 file(MAKE_DIRECTORY "${GENERATED_PROTOBUF_PATH}")
 
-set(COMMON_PB_CPP_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/common/v1/common.pb.cc")
-set(COMMON_PB_H_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/common/v1/common.pb.h")
-set(RESOURCE_PB_CPP_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/resource/v1/resource.pb.cc")
-set(RESOURCE_PB_H_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/resource/v1/resource.pb.h")
-set(TRACE_PB_CPP_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.pb.cc")
-set(TRACE_PB_H_FILE "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.pb.h")
+set(COMMON_PB_CPP_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/common/v1/common.pb.cc")
+set(COMMON_PB_H_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/common/v1/common.pb.h")
+set(RESOURCE_PB_CPP_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/resource/v1/resource.pb.cc")
+set(RESOURCE_PB_H_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/resource/v1/resource.pb.h")
+set(TRACE_PB_CPP_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.pb.cc")
+set(TRACE_PB_H_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.pb.h")
+set(TRACE_GRPC_PB_CPP_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.grpc.pb.cc")
+set(TRACE_GRPC_PB_H_FILE
+    "${GENERATED_PROTOBUF_PATH}/opentelemetry/proto/trace/v1/trace.grpc.pb.h")
 
 foreach(IMPORT_DIR ${PROTOBUF_IMPORT_DIRS})
   list(APPEND PROTOBUF_INCLUDE_FLAGS "-I${IMPORT_DIR}")
 endforeach()
 
 add_custom_command(
-  OUTPUT
-    ${COMMON_PB_H_FILE}
-    ${COMMON_PB_CPP_FILE}
-    ${RESOURCE_PB_H_FILE}
-    ${RESOURCE_PB_CPP_FILE}
-    ${TRACE_PB_H_FILE}
-    ${TRACE_PB_CPP_FILE}
-  COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
-  ARGS
-    "--proto_path=${PROTO_PATH}"
-    ${PROTOBUF_INCLUDE_FLAGS}
+  OUTPUT ${COMMON_PB_H_FILE}
+         ${COMMON_PB_CPP_FILE}
+         ${RESOURCE_PB_H_FILE}
+         ${RESOURCE_PB_CPP_FILE}
+         ${TRACE_PB_H_FILE}
+         ${TRACE_PB_CPP_FILE}
+         ${TRACE_GRPC_PB_H_FILE}
+         ${TRACE_GRPC_PB_CPP_FILE}
+  COMMAND
+    ${PROTOBUF_PROTOC_EXECUTABLE} ARGS "--grpc_out=${GENERATED_PROTOBUF_PATH}"
+    "--proto_path=${PROTO_PATH}" ${PROTOBUF_INCLUDE_FLAGS}
     "--cpp_out=${GENERATED_PROTOBUF_PATH}"
-    ${COMMON_PROTO}
-    ${RESOURCE_PROTO}
-    ${TRACE_PROTO}
-)
-
-include_directories(SYSTEM "${CMAKE_BINARY_DIR}/generated/third_party/opentelemetry-proto")
-
-add_library(opentelemetry_proto OBJECT
-    ${COMMON_PB_CPP_FILE}
-    ${RESOURCE_PB_CPP_FILE}
-    ${TRACE_PB_CPP_FILE})
-if (BUILD_SHARED_LIBS)
+    --plugin=protoc-gen-grpc=$<TARGET_FILE:grpc_cpp_plugin> ${COMMON_PROTO}
+    ${RESOURCE_PROTO} ${TRACE_PROTO})
+
+include_directories(${GENERATED_PROTOBUF_PATH})
+
+add_library(
+  opentelemetry_proto OBJECT ${COMMON_PB_CPP_FILE} ${RESOURCE_PB_CPP_FILE}
+                             ${TRACE_PB_CPP_FILE} ${TRACE_GRPC_PB_CPP_FILE})
+set_target_properties(
+  opentelemetry_proto
+  PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${GENERATED_PROTOBUF_PATH}
+             INTERFACE_LINK_LIBRARIES gRPC::grpc)
+if(BUILD_SHARED_LIBS)
   set_property(TARGET opentelemetry_proto PROPERTY POSITION_INDEPENDENT_CODE ON)
 endif()