k6 pressure test

loadtest/loadtest.js

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+import ws from 'k6/ws';
+import { check, sleep } from 'k6';
+import { Counter, Trend, Rate } from 'k6/metrics';
+
+// =============================================================================
+// CUSTOM METRICS - These will show up in your test results
+// =============================================================================
+const connectionTime = new Trend('ws_connection_time_ms');      // Connection latency
+const messageRTT = new Trend('ws_message_rtt_ms');              // Round-trip time
+const connectionsFailed = new Counter('ws_connections_failed'); // Failed connections
+const messagesReceived = new Counter('ws_messages_received');   // Messages received
+const messagesSent = new Counter('ws_messages_sent');           // Messages sent
+const connectionSuccess = new Rate('ws_connection_success');    // Success rate
+
+// =============================================================================
+// TEST CONFIGURATION
+// =============================================================================
+export const options = {
+  stages: [
+    // Ramp up phase: 0 → 2000 connections over 30 seconds
+    { duration: '10s', target: 500 },
+    { duration: '10s', target: 1000 },
+    { duration: '10s', target: 2000 },
+
+    // Hold at peak: maintain 2000 connections for 1 minute
+    { duration: '60s', target: 2000 },
+
+    // Ramp down: graceful disconnect
+    { duration: '10s', target: 0 },
+  ],
+
+  thresholds: {
+    'ws_connection_time_ms': ['p(95)<1000'],    // 95% connect under 1s
+    'ws_message_rtt_ms': ['p(95)<100'],          // 95% RTT under 100ms
+    'ws_connection_success': ['rate>0.95'],      // 95% success rate
+  },
+};
+
+// =============================================================================
+// MAIN TEST FUNCTION - Runs for each virtual user (VU)
+// =============================================================================
+export default function () {
+  // Distribute users across 20 rooms (simulates realistic usage)
+  const roomId = `loadtest-room-${__VU % 20}`;
+  const url = `ws://localhost:8080/ws/loadtest/${roomId}`;
+
+  const connectStart = Date.now();
+
+  const res = ws.connect(url, {}, function (socket) {
+    // Track connection time
+    const connectDuration = Date.now() - connectStart;
+    connectionTime.add(connectDuration);
+    connectionSuccess.add(1);
+
+    // Variables for RTT measurement
+    let pendingPing = null;
+    let pingStart = 0;
+
+    // =======================================================================
+    // MESSAGE HANDLER - Receives broadcasts from other users
+    // =======================================================================
+    socket.on('message', (data) => {
+      messagesReceived.add(1);
+
+      // Check if this is our ping response (echo from server)
+      if (pendingPing && data.length > 0) {
+        const rtt = Date.now() - pingStart;
+        messageRTT.add(rtt);
+        pendingPing = null;
+      }
+    });
+
+    // =======================================================================
+    // ERROR HANDLER
+    // =======================================================================
+    socket.on('error', (e) => {
+      console.error(`WebSocket error: ${e.error()}`);
+      connectionsFailed.add(1);
+    });
+
+    // =======================================================================
+    // PING LOOP - Send a message every second to measure RTT
+    // =======================================================================
+    socket.setInterval(function () {
+      // Create a simple binary message (mimics Yjs awareness update)
+      // Format: [1, ...payload] where 1 = Awareness message type
+      const timestamp = Date.now();
+      const payload = new Uint8Array([
+        1,  // Message type: Awareness
+        0,  // Payload length (varint)
+      ]);
+
+      pingStart = timestamp;
+      pendingPing = true;
+
+      socket.sendBinary(payload.buffer);
+      messagesSent.add(1);
+
+    }, 1000); // Every 1 second
+
+    // =======================================================================
+    // STAY CONNECTED - Keep connection alive for the test duration
+    // =======================================================================
+    socket.setTimeout(function () {
+      socket.close();
+    }, 90000); // 90 seconds max per connection
+  });
+
+  // =======================================================================
+  // CONNECTION RESULT CHECK
+  // =======================================================================
+  const connected = check(res, {
+    'WebSocket connected': (r) => r && r.status === 101,
+  });
+
+  if (!connected) {
+    connectionsFailed.add(1);
+    connectionSuccess.add(0);
+  }
+
+  // Small sleep to prevent tight loop on connection failure
+  sleep(0.1);
+}
+
+// =============================================================================
+// LIFECYCLE HOOKS
+// =============================================================================
+export function setup() {
+  console.log('========================================');
+  console.log('    WebSocket Load Test Starting');
+  console.log('========================================');
+  console.log('Target: ws://localhost:8080/ws/loadtest/:roomId');
+  console.log('Max VUs: 2000');
+  console.log('Duration: ~100 seconds');
+  console.log('');
+  console.log('Key Metrics to Watch:');
+  console.log('  - ws_connection_time_ms (p95 < 1s)');
+  console.log('  - ws_message_rtt_ms (p95 < 100ms)');
+  console.log('  - ws_connection_success (rate > 95%)');
+  console.log('========================================');
+}
+
+export function teardown(data) {
+  console.log('========================================');
+  console.log('    Load Test Complete!');
+  console.log('========================================');
+  console.log('');
+  console.log('📸 Take a screenshot of the results above');
+  console.log('   for your "Before vs After" comparison!');
+  console.log('========================================');
+}