Auf diese Weise verbrauchen Container **wenig Ressourcen**, eine Menge vergleichbar mit der direkten Ausführung der Prozesse (eine virtuelle Maschine würde viel mehr verbrauchen).

<div class="termy">

```console
$ pip install -r requirements.txt
---> 100%
Successfully installed fastapi pydantic
```

</div>

!!! info
    There are other formats and tools to define and install package dependencies.

### Create the **FastAPI** Code

* Create an `app` directory and enter it.
* Create an empty file `__init__.py`.
* Create a `main.py` file with:

```Python

```

#### Cache Docker

Existe um truque importante nesse `Dockerfile`, primeiro copiamos o **arquivo com as dependências sozinho**, não o resto do código. Deixe-me te contar o porquê disso.

```Dockerfile
COPY ./requirements.txt /code/requirements.txt
```