add json generator to conan

[nilsnolde]

... so downstream apps can use valhalla's conanfile.txt to know where boost is installed. there's no side effects except for an additional file, the cmake build should still work as before.

specifically I'm using valhalla as submodule and instead of generating another conanfile.txt I can use valhalla's if it exports the dependency tree as JSON.

this is what it looks like for valhalla currently:

conanbuildinfo.json

{
  "deps_env_info": {
    "BOOST_ROOT": "/home/nilsnolde/.conan/data/boost/1.71.0/_/_/package/524ea35a8120baabdde02483add58d81bf541327"
  },
  "deps_user_info": {
    "boost": {
      "stacktrace_addr2line_available": "False"
    }
  },
  "dependencies": [
    {
      "version": "1.71.0",
      "description": "Boost provides free peer-reviewed portable C++ source libraries",
      "rootpath": "/home/nilsnolde/.conan/data/boost/1.71.0/_/_/package/524ea35a8120baabdde02483add58d81bf541327",
      "sysroot": "",
      "include_paths": [
        "/home/nilsnolde/.conan/data/boost/1.71.0/_/_/package/524ea35a8120baabdde02483add58d81bf541327/include"
      ],
      "lib_paths": [],
      "bin_paths": [],
      "build_paths": [
        "/home/nilsnolde/.conan/data/boost/1.71.0/_/_/package/524ea35a8120baabdde02483add58d81bf541327/"
      ],
      "res_paths": [],
      "libs": [],
      "system_libs": [],
      "defines": [],
      "cflags": [],
      "cxxflags": [],
      "sharedlinkflags": [],
      "exelinkflags": [],
      "frameworks": [],
      "framework_paths": [],
      "names": {
        "cmake_find_package": "Boost",
        "cmake_find_package_multi": "Boost"
      },
      "filenames": {
        "cmake_find_package": "Boost",
        "cmake_find_package_multi": "Boost"
      },
      "cppflags": [],
      "name": "boost"
    }
  ],
  "settings": {
    "arch": "x86_64",
    "arch_build": "x86_64",
    "build_type": "Release",
    "compiler": "gcc",
    "compiler.libcxx": "libstdc++",
    "compiler.version": "11",
    "os": "Linux",
    "os_build": "Linux"
  },
  "options": {
    "boost": {
      "asio_no_deprecated": "False",
      "buildid": "None",
      "bzip2": "True",
      "debug_level": "0",
      "diagnostic_definitions": "False",
      "error_code_header_only": "False",
      "extra_b2_flags": "None",
      "filesystem_no_deprecated": "False",
      "header_only": "True",
      "i18n_backend": "deprecated",
      "layout": "system",
      "lzma": "False",
      "magic_autolink": "False",
      "multithreading": "True",
      "namespace": "boost",
      "namespace_alias": "False",
      "pch": "True",
      "python_executable": "None",
      "python_version": "None",
      "segmented_stacks": "False",
      "system_no_deprecated": "False",
      "visibility": "hidden",
      "without_atomic": "True",
      "without_chrono": "True",
      "without_container": "True",
      "without_context": "True",
      "without_contract": "True",
      "without_coroutine": "True",
      "without_date_time": "True",
      "without_exception": "True",
      "without_fiber": "True",
      "without_filesystem": "True",
      "without_graph": "True",
      "without_graph_parallel": "True",
      "without_iostreams": "True",
      "without_locale": "True",
      "without_log": "True",
      "without_math": "True",
      "without_mpi": "True",
      "without_program_options": "True",
      "without_python": "True",
      "without_random": "True",
      "without_regex": "True",
      "without_serialization": "True",
      "without_stacktrace": "True",
      "without_system": "True",
      "without_test": "True",
      "without_thread": "True",
      "without_timer": "True",
      "without_type_erasure": "True",
      "without_wave": "True",
      "zlib": "True",
      "zstd": "False"
    }
  }
}

the command for a super-project where valhalla is in ./lib:

conan install --install-folder $PWD/conan_build --remote conancenter lib/valhalla

[kevinkreiser]

i have a question about your other project that uses valhalla as a submodule. how are you including valhalla in that downstream cmake project? i have used add_subdirectory before and it seemed to do the right thing by including all the valhalla targets etc in my project. why then dont the BOOST:: targets also show up for you? i guess im asking are you sure you need that file? granted i know nothing about your project, but just checking 😄

[nilsnolde]

Oh yeah, a cmake build wouldn’t be a problem. It’s a setuptools build for python, so I need all the include paths etc. it’s not even about building Valhalla itself, just about building the binding code.

[kevinkreiser]

if its helpful to someone to have the generated json i dont mind!

[nilsnolde]

can you re-approve @kevinkreiser ? thx!

[kevinkreiser]

seems duplicated with the next line that references both prs, do you want two separate or one with both in it. surely you dont want 3 references?

[nilsnolde]

🤦 thanks!