In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event { #shutdown-event }

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

# Testing Events: lifespan and startup - shutdown { #testing-events-lifespan-and-startup-shutdown }

When you need `lifespan` to run in your tests, you can use the `TestClient` with a `with` statement:

{* ../../docs_src/app_testing/tutorial004.py hl[9:15,18,27:28,30:32,41:43] *}


You can read more details about the ["Running lifespan in tests in the official Starlette documentation site."](https://www.starlette.io/lifespan/#running-lifespan-in-tests)

The process normally is that **you define** in your code what is the message that you will send, the **body of the request**.

You also define in some way at which **moments** your app will send those requests or events.

And **your users** define in some way (for example in a web dashboard somewhere) the **URL** where your app should send those requests.

/// tip

Note that we're using async/await with the new `AsyncClient` - the request is asynchronous.

///

/// warning

If your application relies on lifespan events, the `AsyncClient` won't trigger these events. To ensure they are triggered, use `LifespanManager` from <a href="https://github.com/florimondmanca/asgi-lifespan#usage" class="external-link" target="_blank">florimondmanca/asgi-lifespan</a>.

///

permissions: read-all

jobs:
  analysis:
    name: Scorecard analysis
    runs-on: ubuntu-latest
    permissions:
      # Needed to upload the results to code-scanning dashboard.
      security-events: write
      # Needed to publish results and get a badge (see publish_results below).
      id-token: write
      # Uncomment the permissions below if installing in a private repository.
      # contents: read

        }
    }

    /**
     * Handle node unavailable events
     */
    private void handleNodeUnavailable(WitnessNotification notification) {
        log.warn("Node unavailable: {}", notification.getResourceName());
        // Could trigger failover logic here
    }

    /**
     * Handle node available events
     */
    private void handleNodeAvailable(WitnessNotification notification) {

    - advanced/middleware.md
    - advanced/sub-applications.md
    - advanced/behind-a-proxy.md
    - advanced/templates.md
    - advanced/websockets.md
    - advanced/events.md
    - advanced/testing-websockets.md
    - advanced/testing-events.md
    - advanced/testing-dependencies.md
    - advanced/async-tests.md
    - advanced/settings.md
    - advanced/openapi-callbacks.md
    - advanced/openapi-webhooks.md

In an advanced scenario where you know you need the dependency to be called at every step (possibly multiple times) in the same request instead of using the "cached" value, you can set the parameter `use_cache=False` when using `Depends`:

//// tab | Python 3.8+

```Python hl_lines="1"

* Even dependencies can have dependencies, creating a hierarchy or **"graph" of dependencies**.
* All **automatically handled** by the framework.
* All the dependencies can require data from requests and **augment the path operation** constraints and automatic documentation.
* **Automatic validation** even for *path operation* parameters defined in dependencies.

In this case, it might not be a problem, because it's the same user sending the password.

But if we use the same model for another *path operation*, we could be sending our user's passwords to every client.

/// danger

Never store the plain password of a user or send it in a response like this, unless you know all the caveats and you know what you are doing.

///