workflows: add sanity check for toolchains w/ CXX support

.github/workflows/pr-compile-check.yaml

@@ -78,3 +78,26 @@ jobs:
         run: |
           ldd ./bin/fluent-bit
         working-directory: build
+
+  # Sanity check for compilation w/ CXX support
+  pr-compile-without-cxx:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Setup environment
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y bison cmake flex gcc libssl-dev libyaml-dev
+
+      - name: Checkout Fluent Bit code
+        uses: actions/checkout@v4
+
+      - name: Compile w/ CXX support
+        run: |
+          export CXX=/bin/false
+          export nparallel=$(( $(getconf _NPROCESSORS_ONLN) > 8 ? 8 : $(getconf _NPROCESSORS_ONLN) ))
+          cmake ../
+          make -j $nparallel
+        working-directory: build

cmake/kafka.cmake

@@ -1,4 +1,5 @@
 # kafka cmake
+FLB_OPTION(RDKAFKA_BUILD_CXX      Off)
 FLB_OPTION(RDKAFKA_BUILD_STATIC    On)
 FLB_OPTION(RDKAFKA_BUILD_EXAMPLES Off)
 FLB_OPTION(RDKAFKA_BUILD_TESTS    Off)

lib/librdkafka-2.4.0/CMakeLists.txt

@@ -3,7 +3,12 @@ cmake_minimum_required(VERSION 3.2)
 include("packaging/cmake/parseversion.cmake")
 parseversion("src/rdkafka.h")
 
-project(RdKafka VERSION ${RDKAFKA_VERSION})
+project(RdKafka VERSION ${RDKAFKA_VERSION} LANGUAGES C)
+
+option(RDKAFKA_BUILD_CXX "Enable CXX support" ON)
+if(RDKAFKA_BUILD_CXX)
+  enable_language(CXX)
+endif()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/packaging/cmake/Modules/")
 
@@ -181,7 +186,11 @@ endif()
 
 option(RDKAFKA_BUILD_STATIC "Build static rdkafka library" OFF)
 option(RDKAFKA_BUILD_EXAMPLES "Build examples" ON)
-option(RDKAFKA_BUILD_TESTS "Build tests" ON)
+
+if(RDKAFKA_BUILD_CXX)
+    option(RDKAFKA_BUILD_TESTS "Build tests" ON)
+endif()
+
 if(WIN32)
     option(WITHOUT_WIN32_CONFIG "Avoid including win32_config.h on cmake builds" ON)
 endif(WIN32)
@@ -279,7 +288,10 @@ install(
 )
 
 add_subdirectory(src)
-add_subdirectory(src-cpp)
+
+if(RDKAFKA_BUILD_CXX)
+  add_subdirectory(src-cpp)
+endif()
 
 if(RDKAFKA_BUILD_EXAMPLES)
   add_subdirectory(examples)

lib/librdkafka-2.4.0/examples/CMakeLists.txt

@@ -5,23 +5,31 @@ endif(WIN32)
 add_executable(producer producer.c ${win32_sources})
 target_link_libraries(producer PUBLIC rdkafka)
 
-add_executable(producer_cpp producer.cpp ${win32_sources})
-target_link_libraries(producer_cpp PUBLIC rdkafka++)
+if(RDKAFKA_BUILD_CXX)
+    add_executable(producer_cpp producer.cpp ${win32_sources})
+    target_link_libraries(producer_cpp PUBLIC rdkafka++)
+endif()
 
 add_executable(consumer consumer.c ${win32_sources})
 target_link_libraries(consumer PUBLIC rdkafka)
 
 add_executable(rdkafka_performance rdkafka_performance.c ${win32_sources})
 target_link_libraries(rdkafka_performance PUBLIC rdkafka)
 
-add_executable(rdkafka_example_cpp rdkafka_example.cpp ${win32_sources})
-target_link_libraries(rdkafka_example_cpp PUBLIC rdkafka++)
+if(RDKAFKA_BUILD_CXX)
+    add_executable(rdkafka_example_cpp rdkafka_example.cpp ${win32_sources})
+    target_link_libraries(rdkafka_example_cpp PUBLIC rdkafka++)
+endif()
 
-add_executable(rdkafka_complex_consumer_example_cpp rdkafka_complex_consumer_example.cpp ${win32_sources})
-target_link_libraries(rdkafka_complex_consumer_example_cpp PUBLIC rdkafka++)
+if(RDKAFKA_BUILD_CXX)
+    add_executable(rdkafka_complex_consumer_example_cpp rdkafka_complex_consumer_example.cpp ${win32_sources})
+    target_link_libraries(rdkafka_complex_consumer_example_cpp PUBLIC rdkafka++)
+endif()
 
-add_executable(openssl_engine_example_cpp openssl_engine_example.cpp ${win32_sources})
-target_link_libraries(openssl_engine_example_cpp PUBLIC rdkafka++)
+if(RDKAFKA_BUILD_CXX)
+    add_executable(openssl_engine_example_cpp openssl_engine_example.cpp ${win32_sources})
+    target_link_libraries(openssl_engine_example_cpp PUBLIC rdkafka++)
+endif()
 
 add_executable(misc misc.c ${win32_sources})
 target_link_libraries(misc PUBLIC rdkafka)
@@ -70,7 +78,8 @@ if(NOT WIN32)
     add_executable(rdkafka_complex_consumer_example rdkafka_complex_consumer_example.c)
     target_link_libraries(rdkafka_complex_consumer_example PUBLIC rdkafka)
 
-    add_executable(kafkatest_verifiable_client kafkatest_verifiable_client.cpp)
-    target_link_libraries(kafkatest_verifiable_client PUBLIC rdkafka++)
-
+    if(RDKAFKA_BUILD_CXX)
+        add_executable(kafkatest_verifiable_client kafkatest_verifiable_client.cpp)
+        target_link_libraries(kafkatest_verifiable_client PUBLIC rdkafka++)
+    endif()
 endif(NOT WIN32)

lib/luajit-cmake/CMakeLists.txt

@@ -13,7 +13,7 @@ endif()
 
 get_directory_property(hasParent PARENT_DIRECTORY)
 if(LUAJIT_DIR)
-  project(luajit)
+  project(luajit LANGUAGES C)
   include(LuaJIT.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:luajit> PARENT_SCOPE)
@@ -24,7 +24,7 @@ if(LUAJIT_DIR)
     endif()
   endif()
 elseif(LUA_DIR)
-  project(lua)
+  project(lua LANGUAGES C)
   include(lua.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:lua> PARENT_SCOPE)

lib/nghttp2/CMakeLists.txt

@@ -24,7 +24,7 @@
 
 cmake_minimum_required(VERSION 3.0)
 # XXX using 1.8.90 instead of 1.9.0-DEV
-project(nghttp2 VERSION 1.58.90)
+project(nghttp2 VERSION 1.58.90 LANGUAGES C)
 
 # See versioning rule:
 #  https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
@@ -122,29 +122,31 @@ else()
   set(HINT_NORETURN)
 endif()
 
-include(ExtractValidFlags)
-foreach(_cxx1x_flag -std=c++14)
-  extract_valid_cxx_flags(_cxx1x_flag_supported ${_cxx1x_flag})
-  if(_cxx1x_flag_supported)
-    set(CXX1XCXXFLAGS ${_cxx1x_flag})
-    break()
-  endif()
-endforeach()
+if(NOT ENABLE_LIB_ONLY)
+  include(ExtractValidFlags)
+  foreach(_cxx1x_flag -std=c++14)
+    extract_valid_cxx_flags(_cxx1x_flag_supported ${_cxx1x_flag})
+    if(_cxx1x_flag_supported)
+      set(CXX1XCXXFLAGS ${_cxx1x_flag})
+      break()
+    endif()
+  endforeach()
 
-include(CMakePushCheckState)
-include(CheckCXXSourceCompiles)
-cmake_push_check_state()
-set(CMAKE_REQUIRED_DEFINITIONS "${CXX1XCXXFLAGS}")
-# Check that std::future is available.
-check_cxx_source_compiles("
-#include <vector>
-#include <future>
-int main() { std::vector<std::future<int>> v; }" HAVE_STD_FUTURE)
-# Check that std::map::emplace is available for g++-4.7.
-check_cxx_source_compiles("
-#include <map>
-int main() { std::map<int, int>().emplace(1, 2); }" HAVE_STD_MAP_EMPLACE)
-cmake_pop_check_state()
+  include(CMakePushCheckState)
+  include(CheckCXXSourceCompiles)
+  cmake_push_check_state()
+  set(CMAKE_REQUIRED_DEFINITIONS "${CXX1XCXXFLAGS}")
+  # Check that std::future is available.
+  check_cxx_source_compiles("
+  #include <vector>
+  #include <future>
+  int main() { std::vector<std::future<int>> v; }" HAVE_STD_FUTURE)
+  # Check that std::map::emplace is available for g++-4.7.
+  check_cxx_source_compiles("
+  #include <map>
+  int main() { std::map<int, int>().emplace(1, 2); }" HAVE_STD_MAP_EMPLACE)
+  cmake_pop_check_state()
+endif()
 
 
 # Checks for libraries.
@@ -177,7 +179,7 @@ endif()
 # openssl (for src)
 include(CheckSymbolExists)
 set(HAVE_OPENSSL    ${OPENSSL_FOUND})
-if(OPENSSL_FOUND)
+if(NOT ENABLE_LIB_ONLY AND OPENSSL_FOUND)
   set(OPENSSL_INCLUDE_DIRS  ${OPENSSL_INCLUDE_DIR})
   cmake_push_check_state()
   set(CMAKE_REQUIRED_INCLUDES   "${OPENSSL_INCLUDE_DIR}")