advertise over beacon v2 as metamesh.enrich/<id> so meta-sort's Plugins page can find it (Scan -> Add)

src/beacon-advertise.ts

@@ -0,0 +1,188 @@
+/**
+ * Beacon v2 advertiser — makes this plugin findable by meta-sort's Plugins
+ * page (Scan → Add) without anyone typing its URL.
+ *
+ * Advertises one resource, cap `metamesh.enrich/<manifest id>`, on the beacon
+ * group (239.255.99.1:9099): unsolicited every 10 s, and unicast in reply to
+ * any probe whose `want` matches. Says `bye` on shutdown. It keeps no view of
+ * other nodes — a plugin only needs to be found. Spec:
+ * meta-root docs/project-architecture/beacon-v2.md.
+ *
+ * Env:
+ *   ENABLE_UDP_DISCOVERY  false/0/no/off disables
+ *   BEACON_ADVERTISE_URL  endpoints.http (default http://$HOSTNAME:$PORT)
+ *   BEACON_BINDS          the one meta-sort instance allowed to list it
+ *                         (meta-sort sets this on containers it spawns)
+ *   BEACON_GROUP / BEACON_PORT / BEACON_INTERVAL_MS
+ *
+ * ⚠ MIRRORED FILE. Byte-identical copies live in every TypeScript
+ * metamesh-plugin-*; see meta-root `scripts/check-mirrors.sh`. Never fatal: a
+ * host that blocks multicast logs a warning and the plugin serves on.
+ */
+
+import dgram from 'dgram';
+import { hostname, networkInterfaces } from 'os';
+
+const PROTO = 'beacon';
+const VERSION = 2;
+
+interface Resource {
+    id: string;
+    caps: string[];
+    endpoints: Record<string, string>;
+    binds?: string;
+}
+
+interface NodeInfo {
+    name: string;
+    instance: string;
+    version?: string;
+}
+
+function envNum(key: string): number | undefined {
+    const n = Number(process.env[key]);
+    return Number.isFinite(n) && n > 0 ? n : undefined;
+}
+
+function enabled(): boolean {
+    const v = (process.env.ENABLE_UDP_DISCOVERY ?? '').trim().toLowerCase();
+    return !['false', '0', 'no', 'off'].includes(v);
+}
+
+/** IPv4 addresses of every up, non-internal interface. */
+function interfaceAddresses(): string[] {
+    const out: string[] = [];
+    for (const list of Object.values(networkInterfaces())) {
+        for (const ni of list ?? []) {
+            const v4 = (ni as { family: string | number }).family === 'IPv4' || (ni as { family: string | number }).family === 4;
+            if (v4 && !ni.internal && ni.address) out.push(ni.address);
+        }
+    }
+    return out;
+}
+
+/** Same matching rules as the spec: `*`, `x/*`, optional `@contract`. */
+function capMatches(pattern: string, cap: string): boolean {
+    if (pattern === '*') return true;
+    const split = (s: string): [string, string | null] => {
+        const i = s.lastIndexOf('@');
+        return i >= 0 ? [s.slice(0, i), s.slice(i + 1)] : [s, null];
+    };
+    const [pb, pc] = split(pattern);
+    const [cb, cc] = split(cap);
+    if (pc !== null && cc !== pc) return false;
+    if (pb.endsWith('/*')) {
+        const prefix = pb.slice(0, -2);
+        const rest = cb.startsWith(prefix) ? cb.slice(prefix.length) : '';
+        return rest.startsWith('/') && rest.length > 1;
+    }
+    return pb === cb;
+}
+
+let socket: dgram.Socket | null = null;
+let timer: NodeJS.Timeout | null = null;
+let node: NodeInfo | null = null;
+let resource: Resource | null = null;
+let ifaces: string[] = [];
+let group = '239.255.99.1';
+let udpPort = 9099;
+
+function send(msg: object, dest?: { address: string; port: number }): void {
+    const s = socket;
+    if (!s) return;
+    const body = Buffer.from(JSON.stringify(msg));
+    if (dest) {
+        s.send(body, dest.port, dest.address, () => {});
+        return;
+    }
+    // Once per interface: the default route alone reaches one network.
+    for (const addr of ifaces) {
+        try {
+            s.setMulticastInterface(addr);
+            s.send(body, udpPort, group, () => {});
+        } catch (e) {
+            console.warn(`[beacon] send on ${addr} failed:`, e);
+        }
+    }
+}
+
+function advertise(dest?: { address: string; port: number }): void {
+    if (!node || !resource) return;
+    send({ proto: PROTO, v: VERSION, type: 'advertise', node, resources: [resource] }, dest);
+}
+
+/**
+ * Start advertising this plugin. Call once the HTTP server is listening, so a
+ * consumer that hears it can reach it. Idempotent.
+ */
+export function startBeacon(pluginId: string, version: string, httpPort: number): void {
+    if (socket || !enabled()) return;
+    group = process.env.BEACON_GROUP || group;
+    udpPort = envNum('BEACON_PORT') ?? udpPort;
+    const intervalMs = envNum('BEACON_INTERVAL_MS') ?? 10_000;
+    const instance = process.env.HOSTNAME || hostname();
+    const url = (process.env.BEACON_ADVERTISE_URL || `http://${instance}:${httpPort}`).replace(/\/+$/, '');
+    const binds = (process.env.BEACON_BINDS || '').trim();
+
+    node = { name: `metamesh-plugin-${pluginId}`, instance, ...(version ? { version } : {}) };
+    resource = {
+        id: pluginId,
+        caps: [`metamesh.enrich/${pluginId}`],
+        endpoints: { http: url, manifest: '/manifest' },
+        ...(binds ? { binds } : {}),
+    };
+
+    const s = dgram.createSocket({ type: 'udp4', reuseAddr: true });
+    socket = s;
+    s.on('error', (err) => console.warn('[beacon] socket error:', err.message));
+    s.on('message', (buf, rinfo) => {
+        let m: { proto?: string; v?: number; type?: string; from?: string; want?: string[] };
+        try {
+            m = JSON.parse(buf.toString('utf8'));
+        } catch {
+            return; // foreign traffic on the shared group
+        }
+        if (m?.proto !== PROTO || m.v !== VERSION || m.type !== 'probe' || m.from === instance) return;
+        const want = Array.isArray(m.want) ? m.want : [];
+        if (want.length === 0 || resource!.caps.some((c) => want.some((p) => capMatches(p, c)))) {
+            advertise({ address: rinfo.address, port: rinfo.port });
+        }
+    });
+    s.bind(udpPort, '0.0.0.0', () => {
+        try {
+            s.setMulticastTTL(1);
+        } catch {
+            /* best effort */
+        }
+        ifaces = interfaceAddresses();
+        for (const addr of ifaces) {
+            try {
+                s.addMembership(group, addr);
+            } catch (e) {
+                console.warn(`[beacon] join ${group} on ${addr} failed:`, e);
+            }
+        }
+        console.log(`[beacon] advertising metamesh.enrich/${pluginId} at ${url} on ${group}:${udpPort}`);
+        advertise();
+        timer = setInterval(() => advertise(), intervalMs);
+        timer.unref?.();
+    });
+}
+
+/** Say `bye` so consumers drop this plugin at once. */
+export async function stopBeacon(): Promise<void> {
+    if (!socket || !node) return;
+    if (timer) clearInterval(timer);
+    send({ proto: PROTO, v: VERSION, type: 'bye', node });
+    // Let the bye datagrams leave before the socket closes under them.
+    await new Promise((r) => setTimeout(r, 50));
+    const s = socket;
+    socket = null;
+    await new Promise<void>((resolve) => {
+        try {
+            s.close(() => resolve());
+        } catch {
+            resolve();
+        }
+    });
+}

src/index.ts

@@ -34,6 +34,7 @@ import type {
     ConfigureResponse,
 } from './types.js';
 import { manifest, process as processFile, configure } from './plugin.js';
+import { startBeacon, stopBeacon } from './beacon-advertise.js';
 
 const app = Fastify({ logger: true });
 let ready = false;
@@ -91,12 +92,14 @@ const port = parseInt(process.env.PORT || '8080', 10);
 const host = process.env.HOST || '0.0.0.0';
 
 app.listen({ port, host }).then(() => {
+    startBeacon(manifest.id, manifest.version, port);
     ready = true;
     console.log(`[file-info] Plugin listening on http://${host}:${port}`);
 });
 
 // Graceful shutdown
 process.on('SIGTERM', async () => {
+    await stopBeacon();
     ready = false;
     await app.close();
     process.exit(0);