Lifetimes¶

Lifetimes control how often diwire creates an object.

diwire supports three lifetimes:

Lifetime.TRANSIENT: create a new instance every time
Lifetime.SINGLETON: one instance per container
Lifetime.SCOPED: one instance per active scope (e.g. per request)

Transient vs singleton¶

See the runnable script in Basics (Lifetimes section).

from diwire import Container, Lifetime

class TransientService:
    pass

class SingletonService:
    pass

container = Container(autoregister=False)
container.register(TransientService, lifetime=Lifetime.TRANSIENT)
container.register(SingletonService, lifetime=Lifetime.SINGLETON)

assert container.resolve(TransientService) is not container.resolve(TransientService)
assert container.resolve(SingletonService) is container.resolve(SingletonService)

Scoped¶

Scoped lifetimes are covered in Scopes & cleanup because scopes also define cleanup.

One important rule of thumb:

Use SINGLETON for pure, long-lived services (configuration, stateless clients).
Use SCOPED for per-request/per-job state (DB sessions, unit-of-work, request context).
Use TRANSIENT for lightweight objects and pure coordinators.

Auto-registration lifetime¶

Explicit register() defaults to transient (unless you pass a lifetime).

Auto-registration uses the container’s configuration:

from diwire import Container, Lifetime

container = Container(autoregister_default_lifetime=Lifetime.TRANSIENT)