Registry/container introspection API

[sfermigier]

I have code similar to this (the details are not important), used for debugging:

def inspect_services():
    print(blue("\nServices:"))
    print()

    registry = container.registry
    services = [
        (registered_service.svc_type.__name__, registered_service.factory)
        for registered_service in registry._services.values()
    ]
    services.sort(key=lambda x: x[0].lower())

    rows = []
    for k, v in services:
        name = v.__name__
        module = v.__module__
        rows.append((k, name, module))

    headers = ["Type", "Factory", "Module"]
    print_table(headers, rows)

Instead of relying on a private attribute (_services) it would be great if the registry could provide an API to iterate over the registrations.

[hynek]

This makes sense since we already offer in.

[hynek]

Please check out #106