ceph/cmake/modules/BuildOpentelemetry.cmake

function(target_create _target _lib)
  add_library(${_target} STATIC IMPORTED)
  set_target_properties(
    ${_target} PROPERTIES IMPORTED_LOCATION
                          "${opentelemetry_BINARY_DIR}/${_lib}")
endfunction()

function(build_opentelemetry)
  set(opentelemetry_SOURCE_DIR "${PROJECT_SOURCE_DIR}/src/opentelemetry-cpp")
  set(opentelemetry_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/opentelemetry-cpp")
  set(opentelemetry_cpp_targets opentelemetry_trace opentelemetry_exporter_jaeger_trace)
  set(opentelemetry_CMAKE_ARGS -DCMAKE_POSITION_INDEPENDENT_CODE=ON
                               -DWITH_JAEGER=ON
                               -DBUILD_TESTING=OFF
                               -DCMAKE_BUILD_TYPE=Release
                               -DWITH_EXAMPLES=OFF)

  set(opentelemetry_libs
      ${opentelemetry_BINARY_DIR}/sdk/src/trace/libopentelemetry_trace.a
      ${opentelemetry_BINARY_DIR}/sdk/src/resource/libopentelemetry_resources.a
      ${opentelemetry_BINARY_DIR}/sdk/src/common/libopentelemetry_common.a
      ${opentelemetry_BINARY_DIR}/exporters/jaeger/libopentelemetry_exporter_jaeger_trace.a
      ${opentelemetry_BINARY_DIR}/ext/src/http/client/curl/libhttp_client_curl.a
      ${CURL_LIBRARIES}
  )
  set(opentelemetry_include_dir ${opentelemetry_SOURCE_DIR}/api/include/
                                ${opentelemetry_SOURCE_DIR}/exporters/jaeger/include/
                                ${opentelemetry_SOURCE_DIR}/ext/include/
                                ${opentelemetry_SOURCE_DIR}/sdk/include/)
  # TODO: add target based propogation
  set(opentelemetry_deps opentelemetry_trace opentelemetry_resources opentelemetry_common
                         opentelemetry_exporter_jaeger_trace http_client_curl
			 ${CURL_LIBRARIES})

  if(CMAKE_MAKE_PROGRAM MATCHES "make")
    # try to inherit command line arguments passed by parent "make" job
    set(make_cmd $(MAKE) ${opentelemetry_cpp_targets})
  else()
    set(make_cmd ${CMAKE_COMMAND} --build <BINARY_DIR> --target
                 ${opentelemetry_cpp_targets})
  endif()

  if(WITH_SYSTEM_BOOST)
    list(APPEND opentelemetry_CMAKE_ARGS -DBOOST_ROOT=${BOOST_ROOT})
  else()
    list(APPEND dependencies Boost)
    list(APPEND opentelemetry_CMAKE_ARGS -DBoost_INCLUDE_DIR=${CMAKE_BINARY_DIR}/boost/include)
  endif()

  include(ExternalProject)
  ExternalProject_Add(
    opentelemetry-cpp
    GIT_REPOSITORY https://github.com/ideepika/opentelemetry-cpp.git
    GIT_TAG wip-ceph
    GIT_SHALLOW 1
    SOURCE_DIR ${opentelemetry_SOURCE_DIR}
    PREFIX "opentelemetry-cpp"
    CMAKE_ARGS ${opentelemetry_CMAKE_ARGS}
    BUILD_COMMAND ${make_cmd}
    BINARY_DIR ${opentelemetry_BINARY_DIR}
    INSTALL_COMMAND ""
    BUILD_BYPRODUCTS ${opentelemetry_libs}
    DEPENDS ${dependencies}
    LOG_BUILD ON)

  # CMake doesn't allow to add a list of libraries to the import property, hence
  # we create individual targets and link their libraries which finally
  # interfaces to opentelemetry target
  target_create("opentelemetry_trace" "sdk/src/trace/libopentelemetry_trace.a")
  target_create("opentelemetry_resources"
                "sdk/src/resource/libopentelemetry_resources.a")
  target_create("opentelemetry_common"
                "sdk/src/common/libopentelemetry_common.a")
  target_create("opentelemetry_exporter_jaeger_trace"
                "exporters/jaeger/libopentelemetry_exporter_jaeger_trace.a")
  target_create("http_client_curl"
                "ext/src/http/client/curl/libhttp_client_curl.a")

  # will do all linking and path setting fake include path for
  # interface_include_directories since this happens at build time
  file(MAKE_DIRECTORY ${opentelemetry_include_dir})
  add_library(opentelemetry::libopentelemetry INTERFACE IMPORTED)
  add_dependencies(opentelemetry::libopentelemetry opentelemetry-cpp)
  set_target_properties(
    opentelemetry::libopentelemetry
    PROPERTIES
      INTERFACE_LINK_LIBRARIES "${opentelemetry_deps}"
      INTERFACE_INCLUDE_DIRECTORIES "${opentelemetry_include_dir}")
endfunction()