server with a single resource

server_with_single_resource.bal

import ballerina/http;
import ballerina/log;

@http:WebSocketServiceConfig {
    path: "/hello/ws"
}
service basic on new http:Listener(21005) {
    // The resource is triggered after a successful client connection 
    resource function onOpen(http:WebSocketCaller caller) {
      log:printInfo("connection open");
    }
}