[19515] [INFO] Started server process [19515]
[19515] [INFO] Waiting for application startup.
[19515] [INFO] Application startup complete.
```

</div>

Let's see what each of those options mean:

* `main:app`: This is the same syntax used by Uvicorn, `main` means the Python module named "`main`", so, a file `main.py`. And `app` is the name of the variable that is the **FastAPI** application.

    The `--no-cache-dir` option tells `pip` to not save the downloaded packages locally, as that is only if `pip` was going to be run again to install the same packages, but that's not the case when working with containers.

    !!! note
        The `--no-cache-dir` is only related to `pip`, it has nothing to do with Docker or containers.

!!! tip "Tipp"
    Um alle Konfigurationen und Optionen anzuzeigen, gehen Sie zur Docker-Image-Seite: <a href="https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker" class="external-link" target="_blank">tiangolo/uvicorn-gunicorn-fastapi</a>.

plugins:
  social:
    cards_layout_dir: ../en/layouts
    cards_layout: custom
    cards_layout_options:
      logo: ../en/docs/img/icon-white.svg

[19515] [INFO] Started server process [19515]
[19515] [INFO] Waiting for application startup.
[19515] [INFO] Application startup complete.
```

</div>

Sehen wir uns an, was jede dieser Optionen bedeutet:

    options:
        members:
            - chunk_size
            - charset
            - status_code
            - media_type
            - body
            - background
            - raw_headers
            - render
            - init_headers
            - headers
            - set_cookie
            - delete_cookie

::: fastapi.responses.HTMLResponse
    options:
        members:

El [Tutorial - Guía de Usuario](../tutorial/index.md){.internal-link target=_blank} principal debe ser suficiente para darte un paseo por todas las características principales de **FastAPI**

En las secciones siguientes verás otras opciones, configuraciones, y características adicionales.

!!! tip
    Las próximas secciones **no son necesariamente "avanzadas"**.

    Y es posible que para tu caso, la solución se encuentre en una de estas.

* Select "Python"
* Run the debugger with the option "`Python: Current File (Integrated Terminal)`".

It will then start the server with your **FastAPI** code, stop at your breakpoints, etc.

Here's how it might look:

<img src="/img/tutorial/debugging/image01.png">

---

If you use Pycharm, you can:

* Open the "Run" menu.
* Select the option "Debug...".
* Then a context menu shows up.

browser at `http://localhost:8080`, and its JavaScript is trying to communicate with a backend running at `http://localhost` (because we don't specify a port, the browser will assume the default port `80`).

Then, the browser will send an HTTP `OPTIONS` request to the backend, and if the backend sends the appropriate headers authorizing the communication from this different origin (`http://localhost:8080`) then the browser will let the JavaScript in the frontend send its request to the backend....

    headers = {
        "Origin": "https://localhost.tiangolo.com",
        "Access-Control-Request-Method": "GET",
        "Access-Control-Request-Headers": "X-Example",
    }
    response = client.options("/", headers=headers)
    assert response.status_code == 200, response.text
    assert response.text == "OK"
    assert (
        response.headers["access-control-allow-origin"]
        == "https://localhost.tiangolo.com"