CMakeLists.txt链接librdkafka失败：无法找到RdKafka配置文件

我通过brew install librdkafka安装了2.3.0版本的Apache Kafka C/C++库，但执行依赖该库的CMake命令时失败，提示找不到RdKafkaConfig.cmake或rdkafka-config.cmake文件。在librdkafka的Homebrew安装目录中未找到相关CMake配置文件，但OpenCV的find_package可正常执行。

报错信息 #

CMake Error at CMakeLists.txt:8 (find_package):
  By not providing "FindRdKafka.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "RdKafka", but
  CMake did not find one.

  Could not find a package configuration file provided by "RdKafka" with any
  of the following names:

    RdKafkaConfig.cmake
    rdkafka-config.cmake

  Add the installation prefix of "RdKafka" to CMAKE_PREFIX_PATH or set
  "RdKafka_DIR" to a directory containing one of the above files. If
  "RdKafka" provides a separate development package or SDK, be sure it has
  been installed.

CMakeLists.txt 内容 #

cmake_minimum_required(VERSION 3.5)
project(kafka_producer_cpp)

set(CMAKE_CXX_STANDARD 11)


# Find librdkafka
find_package(RdKafka REQUIRED)
include_directories(${RDKAFKA_INCLUDE_DIRS})

# Find OpenCV
find_package(OpenCV REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})


add_executable(producer producer.cpp)

target_link_libraries(producer ${OpenCV_LIBS} ${RDKAFKA_LIBRARIES})

执行find /opt/homebrew/Cellar/librdkafka/ -iname "*cmake"无结果，而OpenCV目录下存在相关CMake配置文件。

解决方法 #

方法1：手动指定库和头文件路径 #

Homebrew安装的librdkafka未提供CMake配置文件，可跳过find_package，直接手动指定路径：

cmake_minimum_required(VERSION 3.5)
project(kafka_producer_cpp)

set(CMAKE_CXX_STANDARD 11)

# 手动指定librdkafka路径（使用Homebrew全局链接路径，无需写具体版本）
set(LIBRDKAFKA_INCLUDE_DIR /opt/homebrew/include)
set(LIBRDKAFKA_LIBRARY /opt/homebrew/lib/librdkafka.dylib)
set(LIBRDKAFKA_CPP_LIBRARY /opt/homebrew/lib/librdkafka++.dylib)

# 查找OpenCV
find_package(OpenCV REQUIRED)

include_directories(${LIBRDKAFKA_INCLUDE_DIR} ${OpenCV_INCLUDE_DIRS})

add_executable(producer producer.cpp)

target_link_libraries(producer ${OpenCV_LIBS} ${LIBRDKAFKA_LIBRARY} ${LIBRDKAFKA_CPP_LIBRARY})

方法2：自定义FindRdKafka.cmake #

1. 在项目根目录创建cmake/Modules文件夹，新建FindRdKafka.cmake文件：

find_path(RDKAFKA_INCLUDE_DIRS rdkafka.h
          PATHS /opt/homebrew/include)

find_library(RDKAFKA_LIBRARIES rdkafka
             PATHS /opt/homebrew/lib)

find_library(RDKAFKA_CPP_LIBRARIES rdkafka++
             PATHS /opt/homebrew/lib)

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(RdKafka DEFAULT_MSG
                                  RDKAFKA_INCLUDE_DIRS RDKAFKA_LIBRARIES RDKAFKA_CPP_LIBRARIES)

mark_as_advanced(RDKAFKA_INCLUDE_DIRS RDKAFKA_LIBRARIES RDKAFKA_CPP_LIBRARIES)

2. 在CMakeLists.txt开头添加模块路径：

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake/Modules/")

之后原有的find_package(RdKafka REQUIRED)即可正常工作。

方法3：源码编译librdkafka生成CMake配置文件 #

若需要官方CMake配置文件，可手动从源码编译并开启CMake支持：

git clone https://github.com/confluentinc/librdkafka.git
cd librdkafka
mkdir build && cd build
cmake .. -DRDKAFKA_BUILD_EXAMPLES=OFF -DRDKAFKA_BUILD_TESTS=OFF
make install

编译安装后会自动生成RdKafkaConfig.cmake，此时find_package可自动识别。

内容的提问来源于stack exchange，提问作者Tejas Kaushik