Learn about Fastly Compute with WebSockets using a basic starter that sends connections to a backend.
Note: The WebSockets feature handles passthrough connections only. If you want to handle WebSocket connections from clients without having to run a WebSocket backend, see the Fanout Starter Kit.
For more details about this and other starter kits for Compute, see the Fastly Documentation Hub.
The app expects a configured backend named backend that points to a WebSocket server. For example, if the WebSocket server is available at domain websockets.example.com, then you'll need to create a backend on your Compute service named backend with the destination host set to websockets.example.com and port 443. Also set 'Override Host' to the same host value.
After deploying the app and setting up the backend configuration, all connections received by the service will be passed to the backend.
When you create a new service from this starter kit, WebSockets passthrough is enabled automatically.
To enable WebSockets passthrough on an existing Fastly service, type:
fastly products --enable=websocketsIf testing locally, make sure that you have a backend named backend defined in the local_server section of your fastly.toml file:
[local_server.backends]
[local_server.backends.backend]
url = "https://websockets.example.com/"
override_host = "websockets.example.com"The code in this starter kit cannot be used with the fastly::main attribute on the main() entry point. This is because a function decorated with fastly::main is expected to return a response, but handing off to Fanout is an action that does not create a response. Use an undecorated main() function instead, and use Request::from_client() and Response::send_to_client() as needed.
- Fastly CLI 15.2.0 or newer
- Fastly Local Development Server (Viceroy) 0.18.0 or newer
Please see SECURITY.md for guidance on reporting security-related issues.