///

### Lifespan function { #lifespan-function }

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003_py39.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

    - [Container Images](#container-images)
  - [Changelog since v1.34.2](#changelog-since-v1342)
  - [Changes by Kind](#changes-by-kind)
    - [Feature](#feature)
    - [Bug or Regression](#bug-or-regression)
  - [Dependencies](#dependencies)
    - [Added](#added)
    - [Changed](#changed)
    - [Removed](#removed)
- [v1.34.2](#v1342)
  - [Downloads for v1.34.2](#downloads-for-v1342)
    - [Source Code](#source-code-1)

不過，在這兩種情況下，**FastAPI** [仍然很快](index.md#_11){.internal-link target=_blank}至少與你之前的框架相當（或者更快）。

### 依賴項(Dependencies)

同樣適用於[依賴項](tutorial/dependencies/index.md){.internal-link target=_blank}。如果依賴項是一個標準的 `def` 函式，而不是 `async def`，那麼它在外部的執行緒池被運行。

### 子依賴項

///

### WebSockets mit Abhängigkeiten ausprobieren { #try-the-websockets-with-dependencies }

Wenn Ihre Datei `main.py` heißt, führen Sie Ihre Anwendung mit Folgendem aus:

<div class="termy">

```console
$ fastapi dev main.py

    using a job called "copybara".

**5. Copy to Google Internal codebase and run internal CI**

-   Once the PR is in the Google codebase, we make sure it integrates well with
    its dependencies and the rest of the system.
-   Rarely, If the tests fail at this stage, we cannot merge the code.
-   If needed, we may come to you to make some changes. At times, it may not be

     * injection is complete.
     *
     * PostConstruct annotation ensures this method is called after the bean
     * has been constructed and all dependencies have been injected.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {
            logger.debug("Initializing {}", this.getClass().getSimpleName());
        }
        load();

mockserver = { module = "org.testcontainers:mockserver", version.ref = "testcontainers" }
mockserver-client = { module = "org.mock-server:mockserver-client-java-no-dependencies", version.ref = "mockserverClient" }
nativeImageSvm = { module = "org.graalvm.nativeimage:svm", version.ref = "graalvm" }
openjsse = "org.openjsse:openjsse:1.1.14"

    "path": "testing/distributions-core",
    "unitTests": false,
    "functionalTests": false,
    "crossVersionTests": false
  },
  {
    "name": "distributions-dependencies",
    "path": "packaging/distributions-dependencies",
    "unitTests": false,
    "functionalTests": false,
    "crossVersionTests": false
  },
  {
    "name": "distributions-full",
    "path": "packaging/distributions-full",

 *   </tr>
 *   <tr>
 *      <td>requiresDependencyResolution</td>
 *      <td>requiresDependencyResolution = ResolutionScope.&lt;scope&gt;</td>
 *      <td>No</td>
 *      <td>Flags this Mojo as requiring the dependencies in the specified scope (or an implied scope) to be
 *          resolved before it can execute.
 *          <br>
 *          <i>NOTE: Currently supports <b>compile</b>, <b>runtime</b>, and <b>test</b> scopes.</i>

## Example Lambda handler

Install the necessary dependencies.
```sh
pip install flask requests
```

Following is an example lambda handler.
```py
from flask import Flask, request, abort, make_response
import requests

app = Flask(__name__)