mcp-hub-002: WebSocket backend registration and health tracking

src/backend-registry.js

@@ -0,0 +1,47 @@
+class BackendRegistry {
+  constructor() {
+    this.backends = new Map();
+  }
+
+  register(serviceId, ws) {
+    this.backends.set(serviceId, {
+      ws,
+      connectedAt: new Date().toISOString(),
+      lastPing: null,
+    });
+    console.log(`[registry] registered backend: ${serviceId}`);
+  }
+
+  unregister(serviceId) {
+    if (this.backends.has(serviceId)) {
+      this.backends.delete(serviceId);
+      console.log(`[registry] unregistered backend: ${serviceId}`);
+    }
+  }
+
+  get(serviceId) {
+    const entry = this.backends.get(serviceId);
+    return entry ? entry.ws : null;
+  }
+
+  list() {
+    return Array.from(this.backends.entries()).map(([serviceId, entry]) => ({
+      serviceId,
+      connectedAt: entry.connectedAt,
+      lastPing: entry.lastPing,
+    }));
+  }
+
+  updatePing(serviceId) {
+    const entry = this.backends.get(serviceId);
+    if (entry) {
+      entry.lastPing = new Date().toISOString();
+    }
+  }
+
+  count() {
+    return this.backends.size;
+  }
+}
+
+module.exports = new BackendRegistry();