///

## Модуль main в `FastAPI` { #the-main-fastapi }

Теперь давайте посмотрим на модуль `app/main.py`.

Именно сюда вы импортируете и именно здесь вы используете класс `FastAPI`.

Это основной файл вашего приложения, который объединяет всё в одно целое.

И теперь, когда большая часть логики приложения разделена на отдельные модули, основной файл `app/main.py` будет достаточно простым.

/// note | Nota

O comando `uvicorn main:app` refere-se a:

* `main`: o arquivo `main.py` (o "módulo" Python).
* `app`: o objeto criado dentro de `main.py` com a linha `app = FastAPI()`.

É equivalente a:

```Python
from main import app
```

///

Cada programa de servidor ASGI alternativo teria um comando semelhante, você pode ler mais na documentação respectiva.

/// warning | Atenção

    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

     * circumstances.
     */
    public static void main(String[] args) throws IOException {
        int exitCode = new MavenEncCling().run(args, null, null, null, false);
        System.exit(exitCode);
    }

    /**
     * ClassWorld Launcher "enhanced" entry point: returning exitCode and accepts Class World.
     */
    public static int main(String[] args, ClassWorld world) throws IOException {

     * circumstances.
     */
    public static void main(String[] args) throws IOException {
        int exitCode = new MavenShellCling().run(args, null, null, null, false);
        System.exit(exitCode);
    }

    /**
     * ClassWorld Launcher "enhanced" entry point: returning exitCode and accepts Class World.
     */
    public static int main(String[] args, ClassWorld world) throws IOException {

        project.addSourceRoot(new DefaultSourceRoot(
                ProjectScope.MAIN, Language.JAVA_FAMILY, Path.of(basedir.getAbsolutePath(), "src/main/java")));

        assertEquals(1, project.getSourceRoots().size());

        // Try to remove a different directory
        project.removeSourceRoot(ProjectScope.MAIN, Language.JAVA_FAMILY, "src/test/java");

        assertEquals(1, project.getSourceRoots().size());

{* ../../docs_src/bigger_applications/app_an_py39/main.py hl[1,3,7] title["app/main.py"] *}

### Den `APIRouter` importieren { #import-the-apirouter }

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

{* ../../docs_src/bigger_applications/app_an_py39/main.py hl[4:5] title["app/main.py"] *}

<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
```

Sie könnten beispielsweise eine Datei `config.py` haben mit:

{* ../../docs_src/settings/app01_py39/config.py *}

Und dann verwenden Sie diese in einer Datei `main.py`:

{* ../../docs_src/settings/app01_py39/main.py hl[3,11:13] *}

/// tip | Tipp

	<property name="webinf.dir" value="${basedir}/src/main/webapp/WEB-INF" />
	<property name="crawler.dir" value="${basedir}/src/main/webapp/WEB-INF/env/crawler" />
	<property name="suggest.dir" value="${basedir}/src/main/webapp/WEB-INF/env/suggest" />
	<property name="thumbnail.dir" value="${basedir}/src/main/webapp/WEB-INF/env/thumbnail" />
	<property name="site.dir" value="${basedir}/src/main/webapp/WEB-INF/site" />