import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Annotation used to mark fields that represent configuration properties.
 * This annotation provides metadata about how the configuration property
 * should be handled, including its source, type, default value, and whether it's read-only.
 *
 * @since 4.0.0
 */
@Experimental
@Documented
@Retention(RetentionPolicy.CLASS)

## Call `uvicorn` { #call-uvicorn }

In your FastAPI application, import and run `uvicorn` directly:

{* ../../docs_src/debugging/tutorial001.py hl[1,15] *}

### About `__name__ == "__main__"` { #about-name-main }

The main purpose of the `__name__ == "__main__"` is to have some code that is executed when your file is called with:

<div class="termy">

```console
$ python myapp.py
```

But first, let's check some small concepts.

## In a hurry? { #in-a-hurry }

If you don't care about any of these terms and you just need to add security with authentication based on username and password *right now*, skip to the next chapters.

## OAuth2 { #oauth2 }

---
name: Feature request
about: Suggest an idea for this project
title: ''
labels: ''
assignees: ''

---

contact_links:
  - name: Support Request
    url: https://discuss.kubernetes.io

* **Fast to code**: Increase the speed to develop features by about 200% to 300%. *
* **Fewer bugs**: Reduce about 40% of human (developer) induced errors. *
* **Intuitive**: Great editor support. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> everywhere. Less time debugging.

---
name: Feature request
about: Suggest an idea for this project
title: ''
labels: ''
assignees: ''

---

---
name: Feature request
about: Suggest an idea for this project
title: ''
labels: ''
assignees: ''

---

    protected final Class<?>[] parameterTypes;

    /** The return type of the method */
    protected final Class<?> returnType;

    /** Information about parameterized argument types */
    protected final ParameterizedClassDesc[] parameterizedClassDescs;

    /** Information about the parameterized return type */
    protected final ParameterizedClassDesc parameterizedClassDesc;

    /**
     * Constructs an instance.
     *

## Other middlewares { #other-middlewares }

You can later read more about other middlewares in the [Advanced User Guide: Advanced Middleware](../advanced/middleware.md){.internal-link target=_blank}.