Flask (WSGI)

Flask is synchronous and commonly runs view functions in worker threads/processes. diwire works well in this environment with an explicit per-request scope.

Recommended pattern

1. Create a global container at app startup.

2. Enter a "request" scope in before_request and close it in teardown_request.

3. Use container.resolve() (or container_context.resolve()) to inject services into view functions.

Minimal sketch

from flask import Flask, g
from typing import Annotated

from diwire import Container, Injected, Lifetime

app = Flask(__name__)
container = Container()


@app.before_request
def _enter_request_scope() -> None:
    g.diwire_scope = container.enter_scope("request")


@app.teardown_request
def _exit_request_scope(_exc) -> None:
    scope = getattr(g, "diwire_scope", None)
    if scope is not None:
        scope.close()


class Service:
    ...


container.register(Service, lifetime=Lifetime.SCOPED, scope="request")


@app.get("/health")
@container.resolve()  # uses the already-active scope from before_request
def health(service: Annotated[Service, Injected()]) -> dict[str, bool]:
    return {"ok": True}

If you’d rather have the wrapper create the scope per call, pass scope="request" to resolve(), but the hook-based approach is usually a better match for Flask apps.