# 最初のステップ

最もシンプルなFastAPIファイルは以下のようになります:

{* ../../docs_src/first_steps/tutorial001.py *}

これを`main.py`にコピーします。

ライブサーバーを実行します:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]

[project.optional-dependencies]

standard = [
    "fastapi-cli[standard] >=0.0.8",
    # For the test client
    "httpx >=0.23.0,<1.0.0",
    # For templates
    "jinja2 >=3.1.5",
    # For forms and file uploads
    "python-multipart >=0.0.18",
    # To validate email fields
    "email-validator >=2.0.0",
    # Uvicorn with uvloop
    "uvicorn[standard] >=0.12.0",
    # # Settings management
    "pydantic-settings >=2.0.0",

		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errTierReservedName), r.URL)
		return
	}

	// Refresh from the disk in case we had missed notifications about edits from peers.
	if err := globalTierConfigMgr.Reload(ctx, objAPI); err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

	err = globalTierConfigMgr.Add(ctx, cfg, ignoreInUse)
	if err != nil {

## `fastapi dev` { #fastapi-dev }

Running `fastapi dev` initiates development mode.

        PropertiesUtil.load(properties, inputStreamReader);
    }

    /**
     * Test method for
     * {@link org.codelibs.core.io.PropertiesUtil#load(Properties, File)} .
     */
    @Test
    public void testLoadPropertiesFile() {
        final Properties properties = new Properties();
        PropertiesUtil.load(properties, inputFile);

    }

    /**
     * Wraps exception handling for {@link Properties#load(InputStream)}.
     * <p>
     * The input stream is not closed.
     * </p>
     *
     * @param props the property set (must not be {@literal null})
     * @param in the input stream (must not be {@literal null})
     */
    public static void load(final Properties props, final InputStream in) {
        assertArgumentNotNull("props", props);

	if objAPI == nil {
		return np, grid.NewRemoteErr(errServerNotInitialized)
	}

	go func() {
		err := globalTierConfigMgr.Reload(context.Background(), newObjectLayerFn())
		if err != nil {
			peersLogIf(context.Background(), fmt.Errorf("Failed to reload remote tier config %s", err))
		}
	}()

	return np, nerr
}

// ConsoleLogHandler sends console logs of this node back to peer rest client

```console
$ uvicorn main:app --reload

INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [28720]
INFO:     Started server process [28722]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
```

</div>

<details markdown="1">
<summary>Про команди <code>uvicorn main:app --reload</code>...</summary>

# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
# Disable ALL uploads of any kind.
TFCI_ARTIFACT_FINAL_GCS_ENABLE=
TFCI_ARTIFACT_FINAL_GCS_SA_PATH=
TFCI_ARTIFACT_FINAL_GCS_URI=
TFCI_ARTIFACT_FINAL_PYPI_ARGS=
TFCI_ARTIFACT_FINAL_PYPI_ENABLE=
TFCI_ARTIFACT_LATEST_GCS_URI=

///

У каждого альтернативного ASGI‑сервера будет похожая команда; подробнее см. в их документации.

/// warning | Предупреждение

Uvicorn и другие серверы поддерживают опцию `--reload`, полезную в период разработки.

Опция `--reload` потребляет значительно больше ресурсов, менее стабильна и т.п.

Она сильно помогает во время **разработки**, но в **продакшн** её использовать **не следует**.

///