Demo showing singletons added in a bound container, aren't updated in another.

container_bind.py

from dataclasses import dataclass

from wired import ServiceRegistry


@dataclass
class CustomerOne:
    name: str


@dataclass
class CustomerTwo:
    name: str


@dataclass
class PageContext:
    page_name: str


def main():
    registry = ServiceRegistry()
    site_container = registry.create_container(context=None)

    # This site will render two "pages". Each has a resource
    # as the context and some extra information from "the system"
    # as PageContext.
    pages = (
        (CustomerOne('One'), PageContext('index')),
        (CustomerOne('Two'), PageContext('another_page')),
    )
    for (this_context, this_page_context) in pages:
        # Make a "sub-container" for this request, bound to the
        # context of the customer.
        request_container = site_container.bind(context=this_context)

        # Register the PageContext so it can be used elsewhere
        request_container.register_singleton(this_page_context, PageContext)

        # ...later on in the processing, something wants to get, from
        # the per-request subcontainer, the per-request PageContext
        result: PageContext = request_container.get(PageContext)

        # Alas, the second pass through, doesn't have the second page_name.
        # The first pass through filled the cache, and the "subcontainer"
        # doesn't seem to have cache isolation from the previous container.
        result: PageContext = request_container.get(PageContext)
        assert this_page_context.page_name == result.page_name

        # Doesn't matter, but just in case, do some cleanup
        del request_container


if __name__ == '__main__':
    main()