Container validation

Injex can validate the registered dependency graph before your application starts. This catches common wiring mistakes early without constructing service instances.

from injex import Container


class Settings:
    pass


class ApiClient:
    def __init__(self, settings: Settings):
        self.settings = settings


container = Container()
container.add_singleton(Settings)
container.add_transient(ApiClient)

container.assert_valid()

validate()

Use validate() when you want to decide how to report errors.

errors = container.validate()

for error in errors:
    print(error)

Each item is a ValidationError with:

• service: the registered service being checked;
• name: the registration name, if any;
• message: a human-readable explanation.

assert_valid()

Use assert_valid() for startup checks and tests. It raises ContainerValidationException with all collected validation errors.

def build_container() -> Container:
    container = Container()
    configure_services(container)
    container.assert_valid()
    return container

What validation checks

• Missing constructor annotations.
• Missing factory parameter annotations.
• Missing registrations for required dependencies.
• Cyclic dependencies.
• Dependencies declared through @inject property methods.

Validation does not call constructors or factories. Runtime errors inside service constructors still happen when the service is resolved.