replace file discovery by udp discovery

packages/meta-sort-core/src/api/UnifiedAPIServer.ts

@@ -237,7 +237,7 @@ export class UnifiedAPIServer {
       this.setupStatsRoutes();
     }
 
-    // Service discovery — proxies to meta-core's /api/services using the
+    // Service discovery — meta-discovery v1 neighbour list, served from the
     // LeaderClient to resolve meta-core's current URL dynamically.
     this.setupServiceDiscoveryRoutes();
 
@@ -592,33 +592,28 @@ export class UnifiedAPIServer {
   }
 
   /**
-   * Service discovery — proxies to meta-core's /api/services, resolving the
+   * Service discovery — meta-discovery v1. Served from this service's own UDP
-   * current leader's URL via LeaderClient (no hardcoded hostname).
+   * neighbour map; no meta-core round trip, so the nav survives a core outage.
    */
   private setupServiceDiscoveryRoutes(): void {
-    this.app.get('/api/services', async (_request, reply) => {
+    // meta-discovery v1: neighbours heard over UDP, served from this service's
-      try {
+    // own map. Unlike /api/services below it needs no meta-core, so the nav
+    // still renders when the core is down. `services` is kept as an alias
+    // while any older dashboard build is still in circulation.
+    this.app.get('/api/neighbors', async (_request, reply) => {
       const leaderClient = this.kvManager?.getLeaderClient();
       if (!leaderClient) {
-          return reply.status(503).send({ error: 'KVManager not initialized' });
+        return reply.send({ current: 'meta-sort', enabled: false, count: 0, neighbors: [] });
       }
-        const apiUrl = await leaderClient.getApiUrl();
+      const neighbors = leaderClient.getNeighbors();
-        if (!apiUrl) {
+      return reply.send({
-          return reply.status(503).send({ error: 'Leader not available yet' });
+        current: 'meta-sort',
-        }
+        enabled: true,
-        const response = await fetch(`${apiUrl}/api/services`, {
+        count: neighbors.length,
-          signal: AbortSignal.timeout(5000),
+        neighbors,
+        services: neighbors,
+        self: leaderClient.self(),
       });
-        if (!response.ok) {
-          return reply.status(response.status).send({
-            error: `Upstream ${apiUrl} returned ${response.status}`,
-          });
-        }
-        const body = await response.json();
-        return reply.send(body);
-      } catch (err) {
-        return reply.status(502).send({ error: getErrorMessage(err) });
-      }
     });
   }
 

packages/meta-sort-core/src/kv/IKVClient.ts

@@ -139,7 +139,7 @@ export interface KVClientConfig {
 }
 
 /**
- * Leader lock file content format (kv-leader.info)
+ * meta-core's identity and URL set (from its UDP announce, or /urls)
  * Written by meta-core leader, read by other services
  */
 export interface LeaderLockInfo {

packages/meta-sort-core/src/kv/KVManager.ts

@@ -2,13 +2,12 @@
  * KV Manager - Unified manager for KV storage and service discovery
  *
  * This is the main entry point for the KV subsystem. It:
- * 1. Uses LeaderClient to read leader info from meta-core
+ * 1. Uses LeaderClient to locate meta-core over UDP (meta-discovery v1)
  * 2. Creates and manages the KV client (Redis)
- * 3. Handles service discovery registration
  * 4. Manages reconnection on leader changes
  *
- * Note: Leader election is now handled by meta-core (Go sidecar).
+ * Note: there is no leader election. meta-core announces itself on the
- * This service only reads the leader info and connects to Redis.
+ * discovery group; this service listens and connects to its HTTP API.
  *
  * Usage:
  * ```typescript
@@ -112,7 +111,12 @@ export class KVManager {
         this.leaderClient = new LeaderClient({
             metaCoreUrl: this.config.metaCoreUrl,
             serviceName: this.config.serviceName,
-            baseUrl: this.config.baseUrl || `http://${hostname()}:${this.config.apiPort}`,
+        // Browser-facing URL for the nav menu, in the order the spec requires:
+        // PUBLIC_URL (reachable when there is no Caddy perimeter in front — a
+        // debug-direct port) -> BASE_URL (the Caddy URL) -> container host.
+        // Announcing a Caddy URL on a stack with no Caddy running is what puts
+        // dead links in every neighbour's menu.
+            baseUrl: process.env.PUBLIC_URL || this.config.baseUrl || `http://${hostname()}:${this.config.apiPort}`,
         });
 
         // Watch for leader changes
@@ -313,10 +317,6 @@ export class KVManager {
     /**
      * Get service registration instance
      */
-    /** @deprecated File-based registration is gone; always null. */
-    getServiceRegistration(): null {
-        return null;
-    }
 
     /**
      * Check if the KV store is healthy

packages/meta-sort-core/src/kv/ServiceRegistration.ts

@@ -1,199 +0,0 @@
-/**
- * Service Registration using shared filesystem
- *
- * Each service registers itself in /meta-core/services/{service-name}-{hostname}.json
- * with its base URL, status, and heartbeat timestamp.
- *
- * Service discovery is centralized in meta-core - this class only handles registration.
- * For service discovery, use the /api/services endpoint (proxied to meta-core via nginx).
- *
- * Each service must call start() to register itself and begin heartbeat updates.
- * meta-core runs a cleanup process that removes services with stale heartbeats.
- */
-
-import { promises as fs } from 'fs';
-import { hostname } from 'os';
-import type { ServiceInfo } from './IKVClient.js';
-import { isNodeError } from '../types/ExtendedInterfaces.js';
-
-interface ServiceRegistrationConfig {
-    /** Path to META_CORE_VOLUME (e.g., /meta-core) */
-    metaCorePath: string;
-
-    /** Service name */
-    serviceName: string;
-
-    /** Service version (optional, not used in simplified format) */
-    version?: string;
-
-    /** Base URL for the service */
-    apiUrl: string;
-
-    /** Heartbeat interval in ms (default: 30000) */
-    heartbeatInterval?: number;
-
-    /** Stale threshold in ms (default: 60000) */
-    staleThreshold?: number;
-}
-
-export class ServiceRegistration {
-    private config: ServiceRegistrationConfig;
-    private servicesDir: string;
-    private serviceFilePath: string;
-    private heartbeatTimer: NodeJS.Timeout | null = null;
-    private isShuttingDown = false;
-    private currentHostname: string;
-
-    constructor(config: ServiceRegistrationConfig) {
-        this.config = {
-            heartbeatInterval: 30000,
-            staleThreshold: 60000,
-            ...config
-        };
-
-        this.currentHostname = hostname();
-        this.servicesDir = `${this.config.metaCorePath}/services`;
-        // Use hostname-based file naming
-        this.serviceFilePath = `${this.servicesDir}/${this.config.serviceName}-${this.currentHostname}.json`;
-    }
-
-    /**
-     * Ensure services directory exists
-     */
-    private async ensureServicesDir(): Promise<void> {
-        await fs.mkdir(this.servicesDir, { recursive: true });
-    }
-
-    /**
-     * Build service info for this service
-     */
-    private buildServiceInfo(status: ServiceInfo['status']): ServiceInfo {
-        return {
-            name: this.config.serviceName,
-            hostname: this.currentHostname,
-            baseUrl: this.config.apiUrl,
-            status,
-            lastHeartbeat: new Date().toISOString()
-        };
-    }
-
-    /**
-     * Register this service by writing service info to the shared filesystem.
-     * meta-core's cleanup process monitors these files and removes stale entries.
-     */
-    async register(): Promise<void> {
-        await this.ensureServicesDir();
-
-        const info = this.buildServiceInfo('running');
-        await fs.writeFile(this.serviceFilePath, JSON.stringify(info, null, 2));
-
-        console.log(`[ServiceRegistration] Registered ${this.config.serviceName}-${this.currentHostname}`);
-    }
-
-    /**
-     * Update service status
-     */
-    async updateStatus(status: ServiceInfo['status']): Promise<void> {
-        try {
-            const content = await fs.readFile(this.serviceFilePath, 'utf-8');
-            const info = JSON.parse(content) as ServiceInfo;
-
-            info.status = status;
-            info.lastHeartbeat = new Date().toISOString();
-
-            await fs.writeFile(this.serviceFilePath, JSON.stringify(info, null, 2));
-        } catch (error) {
-            console.error('[ServiceRegistration] Failed to update status:', error);
-        }
-    }
-
-    /**
-     * Send heartbeat (update lastHeartbeat timestamp)
-     */
-    async heartbeat(): Promise<void> {
-        try {
-            const content = await fs.readFile(this.serviceFilePath, 'utf-8');
-            const info = JSON.parse(content) as ServiceInfo;
-
-            info.lastHeartbeat = new Date().toISOString();
-
-            await fs.writeFile(this.serviceFilePath, JSON.stringify(info, null, 2));
-        } catch (error) {
-            // If file was deleted, re-register
-            if (isNodeError(error) && error.code === 'ENOENT') {
-                await this.register();
-            } else {
-                console.error('[ServiceRegistration] Heartbeat failed:', error);
-            }
-        }
-    }
-
-    /**
-     * Start heartbeat loop
-     */
-    startHeartbeat(): void {
-        this.heartbeatTimer = setInterval(async () => {
-            if (this.isShuttingDown) return;
-            await this.heartbeat();
-        }, this.config.heartbeatInterval);
-    }
-
-    /**
-     * Stop heartbeat loop
-     */
-    stopHeartbeat(): void {
-        if (this.heartbeatTimer) {
-            clearInterval(this.heartbeatTimer);
-            this.heartbeatTimer = null;
-        }
-    }
-
-    /**
-     * Unregister this service (on shutdown)
-     */
-    async unregister(): Promise<void> {
-        this.isShuttingDown = true;
-        this.stopHeartbeat();
-
-        try {
-            // Remove the service file
-            await fs.unlink(this.serviceFilePath);
-            console.log(`[ServiceRegistration] Unregistered ${this.config.serviceName}-${this.currentHostname}`);
-        } catch (error) {
-            if (!isNodeError(error) || error.code !== 'ENOENT') {
-                console.error('[ServiceRegistration] Failed to unregister:', error);
-            }
-        }
-    }
-
-    // ========================================================================
-    // Lifecycle
-    // ========================================================================
-
-    /**
-     * Full startup sequence: register service and start heartbeat loop.
-     */
-    async start(): Promise<void> {
-        await this.register();
-        this.startHeartbeat();
-    }
-
-    /**
-     * Full shutdown sequence
-     */
-    async stop(): Promise<void> {
-        await this.unregister();
-    }
-
-    // ========================================================================
-    // Getters
-    // ========================================================================
-
-    getServiceFilePath(): string {
-        return this.serviceFilePath;
-    }
-
-    getServicesDir(): string {
-        return this.servicesDir;
-    }
-}

packages/meta-sort-core/src/kv/index.ts

@@ -5,7 +5,8 @@
  * - IKVClient interface for KV storage abstraction
  * - RedisKVClient for Redis-based storage
  * - LeaderClient for reading leader info from meta-core
- * - ServiceRegistration for service registration (discovery is centralized in meta-core)
+ * Services announce and discover over UDP (meta-discovery v1); there is no
+ * separate registration step, so no ServiceRegistration export.
  * - KVManager for unified management of all components
  * - MetadataUtils for flattening/reconstructing nested metadata
  */
@@ -13,6 +14,5 @@
 export * from './IKVClient.js';
 export * from './RedisClient.js';
 export * from './LeaderClient.js';
-export * from './ServiceRegistration.js';
 export * from './KVManager.js';
 export * from './MetadataUtils.js';

packages/meta-sort-ui/src/components/ServiceNav.tsx

@@ -1,5 +1,8 @@
 import { useEffect } from 'react';
-import './meta-service-menu.js';
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore -- plain ES module, no .d.ts; imported for its side effect
+// of defining the custom element.
+import '../meta-service-menu.js';
 
 /**
  * ServiceNav — the neighbouring meta-* services, as a burger menu.