Problem in integrating web socket microservice with api gateway using express-gateway

Question

I am integrating a websocket microservice with api gateway using express-gateway package and I am facing issue in proxying request from client to server via express-gateway. All the microservices including api-gateway are running inside docker container hosted on same bridge network that I defined as some-net.

I have tried how to integrate the websocket server with api-gateway from express-gateway documentation https://www.express-gateway.io/docs/plugins/plugin-development/ where we need to write a plugin and implement websocket proxying in the plugin. This setup is working fine when running on the local machine without containerizing the solution but when I am using the same solution in containers I am not able to connect to websocket.

this is my docker compose file
api_gateway:
    build: ./api_gateway2/
    ports:
      - "3289:3289"
    environment:
      port: "8080"
      HOST_EMAIL_SERVICE: 192.168.64.1
      HOST_TICKET_SERVICE: 192.168.64.1
    volumes:
      - ./api_gateway2:/usr/src/app
      - /usr/src/app/node_modules
    networks:
      - some-net

  notification_service:
    build: ./notification_service
    container_name: notification_service
    # command: npm start
    volumes:
      - ./notification_service:/usr/src/app
    # restart: on-failure
    ports:
      - "8083:8083"
    # network_mode: "host"
    environment:
      PORT: "8083"
      DB_URI: mongodb://mongo-server:27017/service
    depends_on:
      - mongo
    # links: 
      # - mongo
    networks:
      - some-net```

This my gateway config file

```http:
  port: 3289
admin:
  port: 9876
  host: localhost
apiEndpoints:
  notifications:
    methods: "GET"
    host: localhost
    paths:""

serviceEndpoints:
  notificationService:
    url: "http://notification_service:8083"
policies:
  - basic-auth
  - cors
  - expression
  - key-auth
  - log
  - oauth2
  - proxy
  - rate-limit
  - jwt
pipelines:
  default:
  notification:
    apiEndpoints:
      - notifications
    policies:
      - rate-limit: 
        - action:
            max: 10
            windowMs: 1000
      # - jwt:
      #   - action:
      #       jwtExtractor: ['authBearer', 'authScheme', 'header', 'query']
            # secretOrPublicKeyFile: 
            # checkCredentialExistence: false
      - proxy:
          - action:
              serviceEndpoint: notificationService
              ws: true```
              

So when I am hitting http://localhost:3289/notifcation this should ideally connect with my notification service that is running on port 8083 where I am running web sockets but this is giving me 404 not found error

This is my websocket plugin
```module.exports = {
    version: '1.2.0',
    name: "socket",
    schema: {
        "$id": "https://express-gateway.io/schemas/plugins/socket.json"
    },
    init: function (pluginContext) {
        pluginContext.eventBus.on('hot-reload', function ({ type, newConfig }) {
        });
        pluginContext.eventBus.on('http-ready', function ({ httpServer }) {
            try {
                const httpProxy = require('http-proxy')
                const proxy = new httpProxy.createProxyServer({
                    target: {
                        host: 'notification_service',
                        port: 8083
                    }
                });
                //const proxy = new httpProxy.createProxyServer({target: 'http://notification_service:8083'})

                httpServer.on('upgrade', (req, socket, head) => {
                    proxy.ws(req, socket, head);
                })
            } catch (err) {
                throw new Error('proxy error')
            }
        });
    }
};```

I have mentioned localhost in the host but did not work later I thought Since all the containers are running on same network called some-net in my case as mentioned in the docker-compose file I thought of specifying container name in the host field that too did not work. please help me how to solve this problem