<div class="termy">

```console
// এখনো আমরা এনভায়রনমেন্ট ভেরিয়েবল সেট করিনি
$ python main.py

// যেহেতু env var সেট করা হয়নি, তাই আমরা ডিফল্ট ভ্যালু পাচ্ছি

Hello World from Python

// কিন্তু আমরা প্রথমে যদি একটা এনভায়রনমেন্ট ভারিয়েবল তৈরি করে নেই
$ export MY_NAME="Wade Wilson"

// এবং তারপর আবার প্রোগ্রাটিকে কল করি
$ python main.py

// এখন এটি এনভায়রনমেন্ট ভেরিয়েবল রিড করতে পারবে

Hello Wade Wilson from Python

<div class="termy">

```console
// Aquí todavía no configuramos la env var
$ python main.py

// Como no configuramos la env var, obtenemos el valor por defecto

Hello World from Python

// Pero si creamos una variable de entorno primero
$ export MY_NAME="Wade Wilson"

// Y luego llamamos al programa nuevamente
$ python main.py

// Ahora puede leer la variable de entorno

Hello Wade Wilson from Python
```

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file `main.py`, and start `fastapi dev` with:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting development server 🚀

#                                                      Mail
#                                                     ------
# Does it send mock mail? (true: no send actually, logging only)
mail.send.mock = false

# SMTP server settings for main: host:port
mail.smtp.server.main.host.and.port = localhost:25

# The prefix of subject to show test environment or not
mail.subject.test.prefix = 

# The common return path of all mail

# (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`.

## 🛠️ 🔧

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

The file `main.py` would have:

{* ../../docs_src/async_tests/main.py *}

The file `test_main.py` would have the tests for `main.py`, it could look like this now:

{* ../../docs_src/async_tests/test_main.py *}

## Run it { #run-it }

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

Die Datei `main.py` hätte als Inhalt:

{* ../../docs_src/async_tests/main.py *}

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

{* ../../docs_src/async_tests/test_main.py *}

## Es ausführen

```

</div>

/// note

The command `uvicorn main:app` refers to:

* `main`: the file `main.py` (the Python "module").
* `app`: the object created inside of `main.py` with the line `app = FastAPI()`.

It is equivalent to:

```Python
from main import app
```

///

    Set<DependencyScope> dependencyScopes();

    PathScope MAIN_COMPILE = pathScope(
            "main-compile",
            ProjectScope.MAIN,
            DependencyScope.COMPILE_ONLY,
            DependencyScope.COMPILE,
            DependencyScope.PROVIDED);

    PathScope MAIN_RUNTIME =
            pathScope("main-runtime", ProjectScope.MAIN, DependencyScope.COMPILE, DependencyScope.RUNTIME);

    PathScope TEST_COMPILE = pathScope(

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

     <span style="background-color:#007166"><font color="#D3D7CF"> code </font></span>  Importing the FastAPI app object from the module with the
             following code: