modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

without modification, are permitted provided that the following
conditions are met:

Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with
the distribution.

modification, are permitted provided that the following conditions are
met:

   * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.

!!! info
    Webhooks are available in OpenAPI 3.1.0 and above, supported by FastAPI `0.99.0` and above.

## An app with webhooks

        return when (fir) {
            is FirAnnotationCall -> {
                if (unsubstitutedKtSignature.symbol !is KtConstructorSymbol) return null
                @Suppress("UNCHECKED_CAST") // safe because of the above check on targetKtSymbol
                KtAnnotationCall(
                    partiallyAppliedSymbol as KtPartiallyAppliedFunctionSymbol<KtConstructorSymbol>,

FROM ${ISTIO_BASE_REGISTRY}/iptables@sha256:863a23b9b2d6f3f282e651fb62a47d28a7bd19356839367654254f5677cea6fa as distroless

# This will build the final image based on either debug or distroless from above
# hadolint ignore=DL3006
FROM ${BASE_DISTRIBUTION:-debug}

LABEL description="Istio CNI plugin installer."

ARG TARGETARCH
COPY ${TARGETARCH:-amd64}/istio-cni /opt/cni/bin/istio-cni

But for this example, we'll use a very simple HTML document with some JavaScript, all inside a long string.

This, of course, is not optimal and you wouldn't use it for production.

In production you would have one of the options above.

But it's the simplest way to focus on the server-side of WebSockets and have a working example:

```Python hl_lines="2  6-38  41-43"
{!../../../docs_src/websockets/tutorial001.py!}
```

## Create a `websocket`

    implementation("org.gradle.kotlin.kotlin-dsl:org.gradle.kotlin.kotlin-dsl.gradle.plugin:4.4.0")
    // This Kotlin version should only be updated when updating the above kotlin-dsl version
    implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.23")
    implementation("org.gradle.kotlin:gradle-kotlin-dsl-conventions")
    implementation("org.gradle:test-retry-gradle-plugin:1.5.2")

```Python hl_lines="3  25"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

### Create the callback *path operation*

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*:

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.

are already setting **replication** at the cluster level, with multiple **containers**. In those cases, you are better off **building an image from scratch** as described above: [Build a Docker Image for FastAPI](#build-a-docker-image-for-fastapi).

This image would be useful mainly in the special cases described above in [Containers with Multiple Processes and Special Cases](#containers-with-multiple-processes-and-special-cases). For example, if your application is **simple enough** that...