Lifecycle events

Nestipy provides lifecycle hooks similar to NestJS. These hooks let you run logic during startup, after bootstrap, and during shutdown. Hooks can be implemented by providers, controllers, or modules.

Available Hooks

• OnInit with on_startup() runs when an instance is created.
• OnModuleInit with on_module_init() runs after all providers and controllers in a module are created.
• OnApplicationBootstrap with on_application_bootstrap() runs once after the entire app is bootstrapped.
• OnModuleDestroy with on_module_destroy() runs during shutdown before OnDestroy.
• OnDestroy with on_shutdown() runs during shutdown for cleanup.
• OnApplicationShutdown with on_application_shutdown() runs at the end of the shutdown process.

Order of Execution

flowchart TB
  A["Create provider and controller instances"] --> B["OnInit and NestipyModule.on_startup"]
  B --> C["OnModuleInit"]
  C --> D["OnApplicationBootstrap"]
  D --> E["Application running"]
  E --> F["OnModuleDestroy"]
  F --> G["OnDestroy"]
  G --> H["OnApplicationShutdown"]

Notes:

• OnInit runs per instance, immediately after it is created.
• OnModuleInit runs after a module and its imports are resolved and instances are created.
• OnApplicationBootstrap runs once for all providers, controllers, and modules.
• Shutdown hooks run in the order shown above.

Request Lifecycle (HTTP)

This shows the runtime request pipeline for HTTP routes.

flowchart TB
  A["HTTP adapter receives request"] --> B["RouterProxy builds ExecutionContext"]
  B --> C["Reset request context cache"]
  C --> D["Middleware execution"]
  D --> E["Guards"]
  E --> F["Pipes"]
  F --> G["Interceptors before handler"]
  G --> H["Handler execution"]
  H --> I["Interceptors after handler"]
  I --> J["Template rendering (optional)"]
  J --> K["Response normalization"]
  K --> L["Send response"]

  D -.-> X["Exception filter handler"]
  E -.-> X
  F -.-> X
  G -.-> X
  H -.-> X
  X --> K

Notes:

• Request-scoped dependencies are cached using contextvars and cleared at the end of each request.
• Exception filters can transform errors into structured HTTP responses.

Example

Python

from nestipy.common import Injectable
from nestipy.core import OnInit, OnModuleInit, OnApplicationBootstrap
from nestipy.core import OnModuleDestroy, OnDestroy, OnApplicationShutdown


@Injectable()
class ExampleService(
    OnInit,
    OnModuleInit,
    OnApplicationBootstrap,
    OnModuleDestroy,
    OnDestroy,
    OnApplicationShutdown,
):
    async def on_startup(self):
        print("OnInit")

    async def on_module_init(self):
        print("OnModuleInit")

    async def on_application_bootstrap(self):
        print("OnApplicationBootstrap")

    async def on_module_destroy(self):
        print("OnModuleDestroy")

    async def on_shutdown(self):
        print("OnDestroy")

    async def on_application_shutdown(self):
        print("OnApplicationShutdown")

Module Hooks

If your module extends NestipyModule, you can override configure(), on_startup(), and on_shutdown() in addition to the standard hooks above.

Support us

Nestipy is a project released under the MIT license, meaning it's open source and freely available for use and modification. Its development thrives with the generous contributions of these fantastic individuals.