Merge pull request #17 from kiliantyler/feat/lru-cache

Merging so we can fix conflicts before the chat MR, this looks good to me and works fine

README.md

@@ -122,7 +122,7 @@ Add this to your `services.yaml`:
 | Variable | Default | Description |
 | --- | --- | --- |
 | `PORT` | `3000` | The port the web dashboard listens on. Since `--network host` is used, this port opens directly on the host. |
-| `MAX_PEERS` | `10000` | Maximum number of peers to track in the swarm. Unless you're expecting the entire internet to join, the default is probably fine. |
+| `MAX_PEERS` | `1000000` | Maximum number of peers to track in the swarm. Unless you're expecting the entire internet to join, the default is probably fine. |
 
 ## » Usage
 

server.js

@@ -16,11 +16,12 @@ const main = async () => {
   const diagnostics = new DiagnosticsManager();
   const sseManager = new SSEManager();
 
-  peerManager.addOrUpdatePeer(identity.id, peerManager.getSeq(), null);
+  peerManager.addOrUpdatePeer(identity.id, peerManager.getSeq());
 
   const broadcastUpdate = () => {
     sseManager.broadcastUpdate({
       count: peerManager.size,
+      totalUnique: peerManager.totalUniquePeers,
       direct: swarmManager.getSwarm().connections.size,
       id: identity.id,
       diagnostics: diagnostics.getStats(),

src/config/constants.js

@@ -13,7 +13,7 @@ const TOPIC = crypto.createHash("sha256").update(TOPIC_NAME).digest();
  */
 const POW_PREFIX = "0000";
 
-const MAX_PEERS = parseInt(process.env.MAX_PEERS) || 10000;
+const MAX_PEERS = parseInt(process.env.MAX_PEERS) || 1000000;
 const MAX_MESSAGE_SIZE = 2048;
 const MAX_RELAY_HOPS = 2;
 const MAX_CONNECTIONS = 32;

src/p2p/messaging.js

@@ -42,13 +42,11 @@ class MessageHandler {
         if (!sig) return;
 
         try {
-            let key;
-            if (stored && stored.key) {
-                key = stored.key;
-            } else {
-                if (!this.peerManager.canAcceptPeer(id)) return;
-                key = createPublicKey(id);
-            }
+            // Check if we can accept new peers (only matters for new peers)
+            if (!stored && !this.peerManager.canAcceptPeer(id)) return;
+
+            // Derive public key on-demand from peer ID
+            const key = createPublicKey(id);
 
             if (!verifySignature(`seq:${seq}`, sig, key)) {
                 this.diagnostics.increment("invalidSig");
@@ -59,7 +57,7 @@ class MessageHandler {
                 sourceSocket.peerId = id;
             }
 
-            const wasNew = this.peerManager.addOrUpdatePeer(id, seq, key);
+            const wasNew = this.peerManager.addOrUpdatePeer(id, seq);
 
             if (wasNew) {
                 this.diagnostics.increment("newPeersAdded");
@@ -83,10 +81,13 @@ class MessageHandler {
 
         if (!sig) return;
 
-        const stored = this.peerManager.getPeer(id);
-        if (!stored || !stored.key) return;
+        // Only process leave messages for peers we know about
+        if (!this.peerManager.hasPeer(id)) return;
 
-        if (!verifySignature(`type:LEAVE:${id}`, sig, stored.key)) {
+        // Derive public key on-demand from peer ID
+        const key = createPublicKey(id);
+
+        if (!verifySignature(`type:LEAVE:${id}`, sig, key)) {
             this.diagnostics.increment("invalidSig");
             return;
         }

src/state/lru.js

@@ -0,0 +1,52 @@
+/**
+ * Simple LRU (Least Recently Used) Cache
+ * Uses Map's insertion order guarantee to track recency
+ */
+class LRUCache {
+    constructor(capacity) {
+        this.capacity = capacity;
+        this.cache = new Map();
+    }
+
+    get(key) {
+        if (!this.cache.has(key)) return undefined;
+        const value = this.cache.get(key);
+        // Move to end (most recently used)
+        this.cache.delete(key);
+        this.cache.set(key, value);
+        return value;
+    }
+
+    set(key, value) {
+        // Delete first to update position if key exists
+        this.cache.delete(key);
+        this.cache.set(key, value);
+        // Evict oldest if over capacity
+        if (this.cache.size > this.capacity) {
+            const oldestKey = this.cache.keys().next().value;
+            this.cache.delete(oldestKey);
+        }
+    }
+
+    has(key) {
+        return this.cache.has(key);
+    }
+
+    delete(key) {
+        return this.cache.delete(key);
+    }
+
+    get size() {
+        return this.cache.size;
+    }
+
+    /**
+     * Iterate over entries (for cleanup operations)
+     */
+    *entries() {
+        yield* this.cache.entries();
+    }
+}
+
+module.exports = { LRUCache };
+

src/state/peers.js

@@ -1,19 +1,24 @@
 const { MAX_PEERS, PEER_TIMEOUT } = require("../config/constants");
+const { LRUCache } = require("./lru");
+const { HyperLogLog } = require("./hyperloglog");
 
 class PeerManager {
     constructor() {
-        this.seenPeers = new Map();
+        this.seenPeers = new LRUCache(MAX_PEERS);
+        this.uniquePeersHLL = new HyperLogLog(10);
         this.mySeq = 0;
     }
 
-    addOrUpdatePeer(id, seq, key) {
+    addOrUpdatePeer(id, seq) {
         const stored = this.seenPeers.get(id);
         const wasNew = !stored;
 
+        // Track in HyperLogLog for total unique estimation
+        this.uniquePeersHLL.add(id);
+
         this.seenPeers.set(id, {
             seq,
             lastSeen: Date.now(),
-            key,
         });
 
         return wasNew;
@@ -40,7 +45,7 @@ class PeerManager {
         const now = Date.now();
         let removed = 0;
 
-        for (const [id, data] of this.seenPeers) {
+        for (const [id, data] of this.seenPeers.entries()) {
             if (now - data.lastSeen > PEER_TIMEOUT) {
                 this.seenPeers.delete(id);
                 removed++;
@@ -54,6 +59,10 @@ class PeerManager {
         return this.seenPeers.size;
     }
 
+    get totalUniquePeers() {
+        return this.uniquePeersHLL.count();
+    }
+
     incrementSeq() {
         return ++this.mySeq;
     }

src/web/routes.js

@@ -30,6 +30,7 @@ const setupRoutes = (app, identity, peerManager, swarm, sseManager, diagnostics)
 
         const data = JSON.stringify({
             count: peerManager.size,
+            totalUnique: peerManager.totalUniquePeers,
             direct: swarm.getSwarm().connections.size,
             id: identity.id,
             diagnostics: diagnostics.getStats(),
@@ -44,6 +45,7 @@ const setupRoutes = (app, identity, peerManager, swarm, sseManager, diagnostics)
     app.get("/api/stats", (req, res) => {
         res.json({
             count: peerManager.size,
+            totalUnique: peerManager.totalUniquePeers,
             direct: swarm.getSwarm().connections.size,
             id: identity.id,
             diagnostics: diagnostics.getStats(),