build: gRPC cmake module

Co-Authored-By: Leonardo Di Donato <leodidonato@gmail.com>
Signed-off-by: Lorenzo Fontana <lo@linux.com>

cmake/modules/gRPC.cmake

@@ -0,0 +1,103 @@
+#
+# Copyright (C) 2019 The Falco 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.
+#
+
+option(BUILD_STATIC_GRPC
+       "Build a static version of gRPC (useful for building in Operating Systems that don't have the gRPC package)" OFF)
+
+if(NOT BUILD_STATIC_GRPC)
+
+  # zlib
+  include(FindZLIB)
+  set(ZLIB_INCLUDE "${ZLIB_INCLUDE_DIRS}")
+  set(ZLIB_LIB "${ZLIB_LIBRARIES}")
+
+  # protobuf
+  find_program(PROTOC NAMES protoc)
+  find_path(PROTOBUF_INCLUDE NAMES google/protobuf/message.h)
+  find_library(PROTOBUF_LIB NAMES libprotobuf.so)
+  if(PROTOC
+     AND PROTOBUF_INCLUDE
+     AND PROTOBUF_LIB)
+    message(STATUS "Found protobuf: compiler: ${PROTOC}, include: ${PROTOBUF_INCLUDE}, lib: ${PROTOBUF_LIB}")
+  else()
+    message(FATAL_ERROR "Couldn't find system protobuf")
+  endif()
+  
+  # gRPC
+  # todo(fntlnz, leodido): check that gRPC version is greater or equal than 1.8.0
+  find_path(GRPCXX_INCLUDE NAMES grpc++/grpc++.h)
+  if(GRPCXX_INCLUDE)
+    set(GRPC_INCLUDE ${GRPCXX_INCLUDE})
+  else()
+    find_path(GRPCPP_INCLUDE NAMES grpcpp/grpcpp.h)
+    set(GRPC_INCLUDE ${GRPCPP_INCLUDE})
+    add_definitions(-DGRPC_INCLUDE_IS_GRPCPP=1)
+  endif()
+  find_library(GRPC_LIB NAMES grpc)
+  find_library(GRPCPP_LIB NAMES grpc++)
+  if(GRPC_INCLUDE
+     AND GRPC_LIB
+     AND GRPCPP_LIB)
+    message(STATUS "Found grpc: include: ${GRPC_INCLUDE}, C lib: ${GRPC_LIB}, C++ lib: ${GRPCPP_LIB}")
+  else()
+    message(FATAL_ERROR "Couldn't find system grpc")
+  endif()
+  find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin)
+  if(NOT GRPC_CPP_PLUGIN)
+    message(FATAL_ERROR "System grpc_cpp_plugin not found")
+  endif()
+else()
+  find_package(PkgConfig)
+  if(NOT PKG_CONFIG_FOUND)
+    message(FATAL_ERROR "pkg-config binary not found")
+  endif()
+  message(STATUS "Found pkg-config executable: ${PKG_CONFIG_EXECUTABLE}")
+  set(GRPC_SRC "${PROJECT_BINARY_DIR}/grpc-prefix/src/grpc")
+  message(STATUS "Using bundled grpc in '${GRPC_SRC}'")
+  set(GRPC_INCLUDE "${GRPC_SRC}/include")
+  set(GRPC_LIB "${GRPC_SRC}/libs/opt/libgrpc.a")
+  set(GRPCPP_LIB "${GRPC_SRC}/libs/opt/libgrpc++.a")
+  set(GRPC_CPP_PLUGIN "${GRPC_SRC}/bins/opt/grpc_cpp_plugin")
+  # we tell gRPC to compile protobuf for us because
+  # when a gRPC package is not available, like on CentOS,
+  # it's very likely that protobuf will be very outdated
+  set(PROTOBUF_INCLUDE "${GRPC_SRC}/third_party/protobuf/src")
+  set(PROTOC "${PROTOBUF_INCLUDE}/protoc")
+  set(PROTOBUF_LIB "${PROTOBUF_INCLUDE}/.libs/libprotobuf.a")
+  # we tell gRPC to compile zlib for us because
+  # when a gRPC package is not available, like on CentOS,
+  # it's very likely that zlib will be very outdated
+  set(ZLIB_INCLUDE "${GRPC_SRC}/third_party/zlib")
+  set(ZLIB_LIB "${ZLIB_INCLUDE}/libz.a")
+  # get_filename_component(PROTOC_DIR ${PROTOC} PATH)
+  ExternalProject_Add(
+    grpc
+    GIT_REPOSITORY https://github.com/grpc/grpc.git
+    GIT_TAG v1.25.0
+    GIT_SUBMODULES ""
+    BUILD_COMMAND
+      CFLAGS=-Wno-implicit-fallthrough
+      LDFLAGS=-static
+      HAS_SYSTEM_ZLIB=false
+      HAS_SYSTEM_PROTOBUF=false
+      HAS_SYSTEM_CARES=false
+      CONFIGURE_COMMAND sh  -c "cd ${ZLIB_INCLUDE} && ./configure && make"
+      make
+      grpc_cpp_plugin
+      static_cxx
+      static_c
+    BUILD_IN_SOURCE 1
+    BUILD_BYPRODUCTS ${GRPC_LIB} ${GRPCPP_LIB}
+    INSTALL_COMMAND "")
+
+endif()