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

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

1️⃣. 📁 `main.py` 📁 `/code` 📁 🔗 (🍵 🙆 `./app` 📁).

2️⃣. 🏃 Uvicorn & 💬 ⚫️ 🗄 `app` 🎚 ⚪️➡️ `main` (↩️ 🏭 ⚪️➡️ `app.main`).

⤴️ 🔆 Uvicorn 📋 ⚙️ 🆕 🕹 `main` ↩️ `app.main` 🗄 FastAPI 🎚 `app`.

## 🛠️ 🔧

<code>q</code>'s <code>init</code> functions happens before the start of any of <code>p</code>'s.
</p>

<p class="rule">
The completion of all <code>init</code> functions is synchronized before
the start of the function <code>main.main</code>.
</p>

<h3 id="go">Goroutine creation</h3>

<p class="rule">
The <code>go</code> statement that starts a new goroutine
is synchronized before the start of the goroutine's execution.
</p>

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python

// But if we create an environment variable first
$ export MY_NAME="Wade Wilson"

// And then call the program again
$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

## Main **FastAPI** app

And now in the file `sql_app/main.py` let's integrate and use all the other parts we created before.

### Create the database tables

In a very simplistic way create the database tables:

```Python hl_lines="9-11"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

### Create a dependency

* `main`: plik `main.py` ("moduł" w Pythonie).
* `app`: obiekt stworzony w `main.py` w lini `app = FastAPI()`.
* `--reload`: spraw by serwer resetował się po każdej zmianie w kodzie. Używaj tego tylko w środowisku deweloperskim.

</details>

### Wypróbuj

Otwórz link <a href="http://127.0.0.1:8000/items/5?q=somequery" class="external-link" target="_blank">http://127.0.0.1:8000/items/5?q=somequery</a> w przeglądarce.

* `main`: файл `main.py` (модуль Python).
* `app`: объект, созданный внутри `main.py` с помощью строки `app = FastAPI()`.
* `--reload`: перезапуск сервера после изменения кода. Делайте это только во время разработки.

</details>

### Проверка

Откройте браузер на <a href="http://127.0.0.1:8000/items/5?q=somequery" class="external-link" target="_blank">http://127.0.0.1:8000/items/5?q=somequery</a>.

```

</div>

<details markdown="1">
<summary>Informazioni sul comando <code>uvicorn main:app --reload</code>...</summary>

Vediamo il comando `uvicorn main:app` in dettaglio:

* `main`: il file `main.py` (il "modulo" Python).
* `app`: l'oggetto creato dentro `main.py` con la riga di codice `app = FastAPI()`.

## 👑 **FastAPI** 📱

& 🔜 📁 `sql_app/main.py` ➡️ 🛠️ & ⚙️ 🌐 🎏 🍕 👥 ✍ ⏭.

### ✍ 💽 🏓

📶 🙃 🌌 ✍ 💽 🏓:

```Python hl_lines="9-11"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

### ✍ 🔗

✍ 🔗 👈 🔜 🔗 💽 ▶️️ ▶️ 📨 & 🔌 ⚫️ 🔚:

```Python hl_lines="23-29"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

With **FastAPI** you can take the advantage of concurrency that is very common for web development (the same main attraction of NodeJS).

But you can also exploit the benefits of parallelism and multiprocessing (having multiple processes running in parallel) for **CPU bound** workloads like those in Machine Learning systems.

* `main`：`main.py` 文件（一个 Python "模块"）。
* `app`：在 `main.py` 文件中通过 `app = FastAPI()` 创建的对象。
* `--reload`：让服务器在更新代码后重新启动。仅在开发时使用该选项。

</details>

### 检查

使用浏览器访问 <a href="http://127.0.0.1:8000/items/5?q=somequery" class="external-link" target="_blank">http://127.0.0.1:8000/items/5?q=somequery</a>。

你将会看到如下 JSON 响应：

```JSON
{"item_id": 5, "q": "somequery"}
```

你已经创建了一个具有以下功能的 API：