Description

• Add an optional unserializable_handler_fn callback to mrc::pymrc::cast_from_pyobject which will be invoked for any unsupported Python object. Allowing for serializing unsupported object.
  ex:

    pymrc::unserializable_handler_fn_t handler_fn = [](const py::object& source,
                                                       const std::string& path) {
        return nlohmann::json(py::cast<float>(source));
    };

    // decimal.Decimal is not serializable
    py::object Decimal = py::module_::import("decimal").attr("Decimal");
    py::object o       = Decimal("1.0");
    EXPECT_EQ(pymrc::cast_from_pyobject(o, handler_fn), nlohmann::json(1.0));

• Add JSONValues container class which is an immutable container for holding Python values as nlohmann::json objects if possible, and as pybind11::object otherwise. The container can be copied and moved, but the underlying nlohmann::json object is immutable.

• Updates nlohmann_json from 3.9 to 3.11 for patch_inplace method.

• Incorporates ideas from @drobison00's PR Update PythonObjectCache to support get and pop operations, update utils to allow passing of cached python objects. #417 with three key differences:

  1. Changes to the cast_from_pyobject are opt-in when unserializable_handler_fn is provided, otherwise there is no behavior change to the method.
  2. Unserializable objects are stored in JSONValues rather than a global cache.
  3. Does not rely on parsing the place-holder values.

This PR is related to nv-morpheus/Morpheus#1560

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.