GraphQL Subscriptions

Subscriptions provide real-time updates via WebSocket connections. They enable live monitoring of Meshery resources and events.

WebSocket Connection

Subscriptions require a WebSocket connection to the GraphQL endpoint:

ws://localhost:9081/api/system/graphql/query

For secure connections:

wss://your-meshery-server.com/api/system/graphql/query

Events Subscription

Receive real-time platform events (errors, warnings, info messages).

subscription {
  subscribeEvents {
    id
    userID
    actedUpon
    operationID
    systemID
    severity
    action
    status
    category
    description
    metadata
    createdAt
    updatedAt
  }
}

Response Stream:

{
  "data": {
    "subscribeEvents": {
      "id": "event-uuid",
      "userID": "user-uuid",
      "severity": "informational",
      "action": "create",
      "category": "connection",
      "description": "Connection my-cluster created.",
      "createdAt": "2024-03-03T10:30:00Z"
    }
  }
}

Event Severities:

emergency - System is unusable
alert - Action must be taken immediately
critical - Critical conditions
error - Error conditions
warning - Warning conditions
informational - Informational messages
debug - Debug-level messages

Controller Status Subscription

Monitor Meshery Operator, MeshSync, and Broker status in real-time.

subscription ControllerStatus($connectionIDs: [String!]) {
  subscribeMesheryControllersStatus(connectionIDs: $connectionIDs) {
    connectionID
    controller
    status
    version
  }
}

Variables:

{
  "connectionIDs": ["connection-uuid-1", "connection-uuid-2"]
}

Response Stream:

{
  "data": {
    "subscribeMesheryControllersStatus": [
      {
        "connectionID": "connection-uuid-1",
        "controller": "OPERATOR",
        "status": "DEPLOYED",
        "version": "v0.7.0"
      },
      {
        "connectionID": "connection-uuid-1",
        "controller": "MESHSYNC",
        "status": "CONNECTED",
        "version": "v0.7.0"
      },
      {
        "connectionID": "connection-uuid-1",
        "controller": "BROKER",
        "status": "ENABLED",
        "version": "v0.7.0"
      }
    ]
  }
}

Controller Types:

OPERATOR - Meshery Operator
MESHSYNC - MeshSync discovery engine
BROKER - NATS message broker

Controller Statuses:

DEPLOYED - Successfully deployed
NOTDEPLOYED - Not deployed
DEPLOYING - Deployment in progress
UNDEPLOYED - Undeployed
ENABLED - Enabled and running
RUNNING - Running
CONNECTED - Connected
UNKNOWN - Unknown status

Performance Testing Subscription

Watch for changes to performance test profiles.

subscription PerfProfiles($selector: PageFilter!) {
  subscribePerfProfiles(selector: $selector) {
    page
    page_size
    total_count
    profiles {
      id
      name
      duration
      concurrent_request
      qps
      endpoints
      load_generators
      created_at
      updated_at
    }
  }
}

Variables:

{
  "selector": {
    "page": "0",
    "pageSize": "25"
  }
}

Receive real-time performance test results for a specific profile.

subscription PerfResults(
  $selector: PageFilter!
  $profileID: String!
) {
  subscribePerfResults(
    selector: $selector
    profileID: $profileID
  ) {
    page
    page_size
    total_count
    results {
      meshery_id
      name
      mesh
      test_id
      test_start_time
      runner_results
      server_metrics
    }
  }
}

Variables:

{
  "selector": {
    "page": "0",
    "pageSize": "10"
  },
  "profileID": "profile-uuid"
}

Configuration Subscription

Monitor changes to patterns (designs) and filters.

subscription ConfigChanges(
  $patternSelector: PageFilter!
  $filterSelector: PageFilter!
) {
  subscribeConfiguration(
    patternSelector: $patternSelector
    filterSelector: $filterSelector
  ) {
    patterns {
      page
      page_size
      total_count
      patterns {
        id
        name
        visibility
        updated_at
      }
    }
    filters {
      page
      page_size
      total_count
      filters {
        id
        name
        visibility
        updated_at
      }
    }
  }
}

Variables:

{
  "patternSelector": {
    "page": "0",
    "pageSize": "25"
  },
  "filterSelector": {
    "page": "0",
    "pageSize": "25"
  }
}

Cluster Resources Subscription

Watch Kubernetes cluster resources in real-time.

subscription ClusterResources(
  $k8scontextIDs: [String!]
  $namespace: String!
) {
  subscribeClusterResources(
    k8scontextIDs: $k8scontextIDs
    namespace: $namespace
  ) {
    resources {
      kind
      count
    }
  }
}

Variables:

{
  "k8scontextIDs": ["context-uuid"],
  "namespace": "default"
}

Response Stream:

{
  "data": {
    "subscribeClusterResources": {
      "resources": [
        { "kind": "Pod", "count": 42 },
        { "kind": "Service", "count": 15 },
        { "kind": "Deployment", "count": 8 }
      ]
    }
  }
}

Kubernetes Contexts Subscription

Monitor Kubernetes connection/context changes.

subscription K8sContexts($selector: PageFilter!) {
  subscribeK8sContext(selector: $selector) {
    total_count
    contexts {
      id
      name
      server
      version
      deployment_type
      connection_id
      created_at
      updated_at
    }
  }
}

MeshModel Summary Subscription

Watch for changes in MeshModel statistics.

subscription MeshModelSummary($selector: MeshModelSummarySelector!) {
  subscribeMeshModelSummary(selector: $selector) {
    components {
      name
      count
    }
    relationships {
      name
      count
    }
  }
}

Variables:

{
  "selector": {
    "type": "models"
  }
}

JavaScript Implementation

Using graphql-ws

import { createClient } from 'graphql-ws';

const client = createClient({
  url: 'ws://localhost:9081/api/system/graphql/query',
  connectionParams: {
    Authorization: `Bearer ${token}`
  },
  on: {
    connected: () => console.log('WebSocket connected'),
    error: (error) => console.error('WebSocket error:', error),
    closed: () => console.log('WebSocket closed')
  }
});

// Subscribe to events
const unsubscribe = client.subscribe(
  {
    query: `
      subscription {
        subscribeEvents {
          id
          severity
          description
          createdAt
        }
      }
    `
  },
  {
    next: (result) => {
      console.log('Event received:', result.data.subscribeEvents);
    },
    error: (error) => {
      console.error('Subscription error:', error);
    },
    complete: () => {
      console.log('Subscription complete');
    }
  }
);

// Unsubscribe when done
// unsubscribe();

Using Apollo Client

import { ApolloClient, InMemoryCache, split, HttpLink } from '@apollo/client';
import { GraphQLWsLink } from '@apollo/client/link/subscriptions';
import { getMainDefinition } from '@apollo/client/utilities';
import { createClient } from 'graphql-ws';

const httpLink = new HttpLink({
  uri: 'http://localhost:9081/api/system/graphql/query',
  headers: {
    Authorization: `Bearer ${token}`
  }
});

const wsLink = new GraphQLWsLink(
  createClient({
    url: 'ws://localhost:9081/api/system/graphql/query',
    connectionParams: {
      Authorization: `Bearer ${token}`
    }
  })
);

const splitLink = split(
  ({ query }) => {
    const definition = getMainDefinition(query);
    return (
      definition.kind === 'OperationDefinition' &&
      definition.operation === 'subscription'
    );
  },
  wsLink,
  httpLink
);

const client = new ApolloClient({
  link: splitLink,
  cache: new InMemoryCache()
});

// Use subscription
import { useSubscription, gql } from '@apollo/client';

const EVENTS_SUBSCRIPTION = gql`
  subscription {
    subscribeEvents {
      id
      severity
      description
      createdAt
    }
  }
`;

function EventsComponent() {
  const { data, loading, error } = useSubscription(EVENTS_SUBSCRIPTION);

  if (loading) return <p>Loading...</p>;
  if (error) return <p>Error: {error.message}</p>;

  return (
    <div>
      <h3>Latest Event:</h3>
      <p>{data?.subscribeEvents?.description}</p>
    </div>
  );
}

React Hook Example

import { useEffect, useState } from 'react';
import { createClient } from 'graphql-ws';

function useEventsSubscription(token) {
  const [events, setEvents] = useState([]);
  const [error, setError] = useState(null);

  useEffect(() => {
    const client = createClient({
      url: 'ws://localhost:9081/api/system/graphql/query',
      connectionParams: {
        Authorization: `Bearer ${token}`
      }
    });

    const unsubscribe = client.subscribe(
      {
        query: `
          subscription {
            subscribeEvents {
              id
              severity
              description
              createdAt
            }
          }
        `
      },
      {
        next: (result) => {
          setEvents(prev => [result.data.subscribeEvents, ...prev].slice(0, 100));
        },
        error: (err) => {
          setError(err);
        }
      }
    );

    return () => unsubscribe();
  }, [token]);

  return { events, error };
}

// Usage
function EventsLog() {
  const { events, error } = useEventsSubscription(token);

  if (error) return <div>Error: {error.message}</div>;

  return (
    <div>
      {events.map(event => (
        <div key={event.id}>
          <span className={event.severity}>{event.severity}</span>
          <p>{event.description}</p>
          <time>{new Date(event.createdAt).toLocaleString()}</time>
        </div>
      ))}
    </div>
  );
}

Python Implementation

import asyncio
import websockets
import json

async def subscribe_events(token):
    uri = "ws://localhost:9081/api/system/graphql/query"
    
    # Connection initialization message for graphql-ws protocol
    init_message = {
        "type": "connection_init",
        "payload": {
            "Authorization": f"Bearer {token}"
        }
    }
    
    # Subscription message
    subscribe_message = {
        "id": "1",
        "type": "start",
        "payload": {
            "query": """
                subscription {
                    subscribeEvents {
                        id
                        severity
                        description
                        createdAt
                    }
                }
            """
        }
    }
    
    async with websockets.connect(uri, subprotocols=["graphql-ws"]) as websocket:
        # Initialize connection
        await websocket.send(json.dumps(init_message))
        
        # Wait for connection acknowledgment
        response = await websocket.recv()
        print(f"Connection response: {response}")
        
        # Send subscription
        await websocket.send(json.dumps(subscribe_message))
        
        # Receive events
        while True:
            message = await websocket.recv()
            data = json.loads(message)
            
            if data.get("type") == "data":
                event = data["payload"]["data"]["subscribeEvents"]
                print(f"Event: [{event['severity']}] {event['description']}")
            elif data.get("type") == "complete":
                break

# Run subscription
asyncio.run(subscribe_events('your-token'))

Best Practices

Connection Management

Reconnect on Disconnect: Implement automatic reconnection logic
Heartbeat: Send periodic pings to keep connection alive
Clean Shutdown: Properly unsubscribe before closing

Resource Management

Limit Active Subscriptions: Don’t subscribe to too many streams simultaneously
Pagination: Use appropriate page sizes for bulk subscriptions
Filter Early: Apply filters to reduce data volume

Error Handling

Handle Connection Errors: Network failures, authentication errors
Handle Subscription Errors: Invalid queries, authorization failures
Graceful Degradation: Fall back to polling if WebSocket fails

Troubleshooting

Connection Refused

Issue: Cannot establish WebSocket connection Solution:

Verify Meshery Server is running
Check firewall rules allow WebSocket connections
Ensure using correct protocol (ws:// or wss://)

Authentication Failed

Issue: WebSocket connection closes immediately Solution:

Verify token is valid and not expired
Check token is included in connectionParams
Ensure token has necessary permissions

No Data Received

Issue: Subscription established but no events received Solution:

Verify filters are not too restrictive
Check connection IDs are valid
Ensure relevant events are being generated

Overview

REST API

GraphQL API

GraphQL Subscriptions

WebSocket Connection

Events Subscription

Controller Status Subscription

Performance Testing Subscription

Configuration Subscription

Cluster Resources Subscription

Kubernetes Contexts Subscription

MeshModel Summary Subscription

JavaScript Implementation

Using graphql-ws

Using Apollo Client

React Hook Example

Python Implementation

Best Practices

Connection Management

Resource Management

Error Handling

Troubleshooting

Connection Refused

Authentication Failed

No Data Received

Build docs developers (and LLMs) love

Overview

REST API

GraphQL API

Documentation Index

​WebSocket Connection

​Events Subscription

​Subscribe to Events

​Controller Status Subscription

​Subscribe to Meshery Controllers Status

​Performance Testing Subscription

​Subscribe to Performance Profiles

​Subscribe to Performance Results

​Configuration Subscription

​Subscribe to Configuration Changes

​Cluster Resources Subscription

​Subscribe to Cluster Resources

​Kubernetes Contexts Subscription

​Subscribe to K8s Context Changes

​MeshModel Summary Subscription

​Subscribe to MeshModel Summary

​JavaScript Implementation

​Using graphql-ws

​Using Apollo Client

​React Hook Example

​Python Implementation

​Best Practices

​Connection Management

​Resource Management

​Error Handling

​Troubleshooting

​Connection Refused

​Authentication Failed

​No Data Received

Build docs developers (and LLMs) love

WebSocket Connection

Events Subscription

Subscribe to Events

Controller Status Subscription

Subscribe to Meshery Controllers Status

Performance Testing Subscription

Subscribe to Performance Profiles

Subscribe to Performance Results

Configuration Subscription

Subscribe to Configuration Changes

Cluster Resources Subscription

Subscribe to Cluster Resources

Kubernetes Contexts Subscription

Subscribe to K8s Context Changes

MeshModel Summary Subscription

Subscribe to MeshModel Summary

JavaScript Implementation

Using graphql-ws

Using Apollo Client

React Hook Example

Python Implementation

Best Practices

Connection Management

Resource Management

Error Handling

Troubleshooting

Connection Refused

Authentication Failed

No Data Received