Lifecycle Hooks¶

dijay supports @module.on_bootstrap and @module.on_shutdown decorators to execute logic when the container starts or stops.

Method Hooks¶

The most common pattern is decorating methods within @injectable classes:

from dijay import module, injectable

@injectable()
class Database:
    @module.on_bootstrap
    async def connect(self):
        print("Database connected!")

    @module.on_shutdown
    async def disconnect(self):
        print("Database disconnected!")

When the container bootstraps, it resolves the Database singleton and calls connect(). On shutdown, it calls disconnect().

Standalone Hooks¶

Hooks can also be standalone functions registered on a specific container. Parameters are injected automatically:

from dijay import module, instance

c = instance()

@module.on_bootstrap(c)
async def log_startup(db: Database):
    print(f"App started with {db}")

If no container is provided, the hook is registered on the global container:

@module.on_bootstrap
async def log_startup(db: Database):
    print(f"App started with {db}")

Sync and Async¶

Hooks can be synchronous or asynchronous — the container handles both:

@module.on_bootstrap
def sync_hook():
    print("Sync hook!")

@module.on_bootstrap
async def async_hook():
    print("Async hook!")

Triggering Hooks¶

Async Context Manager (recommended)¶

Hooks are triggered automatically when using the container as an async context manager:

async with Container.from_module(AppModule) as container:
    # @module.on_bootstrap hooks have already run here
    ...
# @module.on_shutdown hooks run when exiting the block

Manual Control¶

You can also call hooks explicitly:

container = Container.from_module(AppModule)
await container.bootstrap()
# ... app logic ...
await container.shutdown()

Note

shutdown() only runs hooks for singletons that were actually created during the container's lifetime.