```Python hl_lines="1  3  7" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

### Den `APIRouter` importieren

Jetzt importieren wir die anderen Submodule, die `APIRouter` haben:

```Python hl_lines="4-5" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Die Datei `main.py` hätte als Inhalt:

```Python
{!../../../docs_src/async_tests/main.py!}
```

Die Datei `test_main.py` hätte die Tests für `main.py`, das könnte jetzt so aussehen:

```Python
{!../../../docs_src/async_tests/test_main.py!}
```

## Es ausführen

## The main `FastAPI`

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI`

```

</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.
    * You can imagine that `main:app` is equivalent to a Python `import` statement like:

        ```Python
        from main import app
        ```

# (1)
COPY ./main.py /code/

# (2)
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "80"]
```

1. Copy the `main.py` file to the `/code` directory directly (without any `./app` directory).

2. Run Uvicorn and tell it to import the `app` object from `main` (instead of importing from `app.main`).

    <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory>
    <scriptSourceDirectory>${project.basedir}/src/main/scripts</scriptSourceDirectory>
    <testSourceDirectory>${project.basedir}/src/test/java</testSourceDirectory>
    <resources>
      <resource>
        <directory>${project.basedir}/src/main/resources</directory>
      </resource>
      <resource>

В вашем FastAPI приложении, импортируйте и вызовите `uvicorn` напрямую:

```Python hl_lines="1  15"
{!../../../docs_src/debugging/tutorial001.py!}
```

### Описание `__name__ == "__main__"`

Главная цель использования `__name__ == "__main__"` в том, чтобы код выполнялся при запуске файла с помощью:

<div class="termy">

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

</div>

# Advanced User Guide

## Additional Features

The main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} should be enough to give you a tour through all the main features of **FastAPI**.

In the next sections you will see other options, configurations, and additional features.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

<span style="color: green;">INFO</span>:     Application startup complete.
```

</div>

!!! note "Nota"
    El comando `uvicorn main:app` se refiere a:

    * `main`: el archivo `main.py` (el "módulo" de Python).
    * `app`: el objeto creado dentro de `main.py` con la línea `app = FastAPI()`.
    * `--reload`: hace que el servidor se reinicie cada vez que cambia el código. Úsalo únicamente para desarrollo.

* `main:app`: Das ist die gleiche Syntax, die auch von Uvicorn verwendet wird. `main` bedeutet das Python-Modul mit dem Namen `main`, also eine Datei `main.py`. Und `app` ist der Name der Variable, welche die **FastAPI**-Anwendung ist.
    * Stellen Sie sich einfach vor, dass `main:app` einer Python-`import`-Anweisung wie der folgenden entspricht:

        ```Python
        from main import app
        ```