```Dockerfile
# ⛔️ No hagas esto
CMD fastapi run app/main.py --port 80
```

Asegúrate de siempre usar la **forma exec** para garantizar que FastAPI pueda cerrarse de manera adecuada y que [los eventos de lifespan](../advanced/events.md){.internal-link target=_blank} sean disparados.

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event { #shutdown-event }

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

        // Create different implementations
        SearchLogEvent event1 = new TestSearchLogEvent("id1", 1L, "type1");
        SearchLogEvent event2 = new NullSearchLogEvent();
        SearchLogEvent event3 = new EmptySearchLogEvent();

        // Test polymorphic behavior
        SearchLogEvent[] events = { event1, event2, event3 };

        for (SearchLogEvent event : events) {
            // All methods should be callable without exceptions

# Testing Events: lifespan and startup - shutdown { #testing-events-lifespan-and-startup-shutdown }

When you need `lifespan` to run in your tests, you can use the `TestClient` with a `with` statement:

{* ../../docs_src/app_testing/tutorial004.py hl[9:15,18,27:28,30:32,41:43] *}


You can read more details about the ["Running lifespan in tests in the official Starlette documentation site."](https://www.starlette.io/lifespan/#running-lifespan-in-tests)

{* ../../docs_src/events/tutorial003.py hl[14:19] *}

함수의 첫 번째 부분, 즉 `yield` 이전의 코드는 애플리케이션이 시작되기 **전에** 실행됩니다.

그리고 `yield` 이후의 부분은 애플리케이션이 완료된 후 **나중에** 실행됩니다.

### 비동기 컨텍스트 매니저

함수를 확인해보면, `@asynccontextmanager`로 장식되어 있습니다.

이것은 함수를 "**비동기 컨텍스트 매니저**"라고 불리는 것으로 변환시킵니다.

{* ../../docs_src/events/tutorial003.py hl[1,13] *}

    @Subscribe
    public void listenForStrings(String event) {
      eventsReceived.add(event);
      ready = false;
      try {
        bus.post(SECOND);
      } finally {
        ready = true;
      }
    }

    @Subscribe
    public void listenForDoubles(Double event) {
      assertTrue("I received an event when I wasn't ready!", ready);
      eventsReceived.add(event);
    }
  }

                .build();

        LogEvent event3 = Log4jLogEvent.newBuilder()
                .setLoggerName("third.logger")
                .setLevel(Level.ERROR)
                .setMessage(new SimpleMessage("test message 3"))
                .build();

        LogEvent result1 = policy.rewrite(event1);
        LogEvent result2 = policy.rewrite(event2);
        LogEvent result3 = policy.rewrite(event3);

public class StringCatcher {
  private final List<String> events = new ArrayList<>();

  @Subscribe
  public void hereHaveAString(@Nullable String string) {
    events.add(string);
  }

  public void methodWithoutAnnotation(@Nullable String string) {
    Assert.fail("Event bus must not call methods without @Subscribe!");
  }

  public List<String> getEvents() {
    return events;
  }

    assertEquals("The dead event should wrap the original event.", EVENT, events.get(0).getEvent());
  }

  public void testDeadEventPosting() {
    GhostCatcher catcher = new GhostCatcher();
    bus.register(catcher);

    bus.post(new DeadEvent(this, EVENT));

    List<DeadEvent> events = catcher.getEvents();
    assertEquals("The explicit DeadEvent should be delivered.", 1, events.size());

public class StringCatcher {
  private final List<String> events = new ArrayList<>();

  @Subscribe
  public void hereHaveAString(@Nullable String string) {
    events.add(string);
  }

  public void methodWithoutAnnotation(@Nullable String string) {
    Assert.fail("Event bus must not call methods without @Subscribe!");
  }

  public List<String> getEvents() {
    return events;
  }