fix(playground): server-side memory cleanup on session expiry + startup purge (DAK-6975) (#231)

BUG 1: sweep() only removed sessions from the in-memory Map — engine memories
persisted forever in RocksDB. Now tracks namespaces per session and calls
DELETE /v1/namespaces/{ns} on expiry (both sweep timer and resolve-time expiry).

BUG 6: Historical playground-demo-* namespaces accumulated from all past sessions.
Added startup purge that lists all namespaces and deletes playground-demo-* ones.

4 new tests: onExpire callback, resolve-time cleanup, trackNamespace dedup, no-op
when no namespaces tracked. All 64 tests pass.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: ferhimedamine

docker/playground/proxy/index.js

@@ -1,17 +1,78 @@
 'use strict';
 
+const http = require('http');
 const { config } = require('./config');
 const { createServer } = require('./server');
 const { SessionStore } = require('./sessions');
+const { NS_PREFIX } = require('./namespace');
 
 // =============================================================================
 // Entrypoint — wires config + session store + HTTP server and starts listening.
 // =============================================================================
 
+function deleteNamespace(ns) {
+  const url = new URL(config.upstreamUrl + '/v1/namespaces/' + encodeURIComponent(ns));
+  const headers = { 'Content-Type': 'application/json' };
+  if (config.rootApiKey) headers['authorization'] = `Bearer ${config.rootApiKey}`;
+
+  const req = http.request({
+    protocol: url.protocol,
+    hostname: url.hostname,
+    port: url.port || 80,
+    method: 'DELETE',
+    path: url.pathname,
+    headers,
+    timeout: 10000,
+  });
+  req.on('error', () => {});
+  req.on('timeout', () => req.destroy());
+  req.end();
+}
+
+function purgeStaleNamespaces() {
+  const url = new URL(config.upstreamUrl + '/v1/namespaces');
+  const headers = { 'Content-Type': 'application/json' };
+  if (config.rootApiKey) headers['authorization'] = `Bearer ${config.rootApiKey}`;
+
+  const req = http.request({
+    protocol: url.protocol,
+    hostname: url.hostname,
+    port: url.port || 80,
+    method: 'GET',
+    path: url.pathname,
+    headers,
+    timeout: 15000,
+  }, (res) => {
+    const chunks = [];
+    res.on('data', (c) => chunks.push(c));
+    res.on('end', () => {
+      try {
+        const body = JSON.parse(Buffer.concat(chunks).toString('utf8'));
+        const nsList = Array.isArray(body) ? body : (body.namespaces || []);
+        const prefix = '_dakera_agent_' + NS_PREFIX + '-';
+        let purged = 0;
+        for (const entry of nsList) {
+          const name = typeof entry === 'string' ? entry : (entry.name || entry.id || '');
+          if (name.startsWith(prefix)) {
+            deleteNamespace(name);
+            purged++;
+          }
+        }
+        if (purged > 0) {
+          console.log(`[sandbox-proxy] startup purge: deleting ${purged} stale playground namespace(s)`);
+        }
+      } catch (_) {}
+    });
+  });
+  req.on('error', (e) => {
+    console.warn(`[sandbox-proxy] startup purge failed: ${e.message}`);
+  });
+  req.on('timeout', () => req.destroy());
+  req.end();
+}
+
 function main() {
   if (!config.rootApiKey) {
-    // Fail loud rather than silently forwarding unauthenticated requests to an
-    // auth-enabled engine (would produce confusing upstream 401s).
     console.warn(
       '[sandbox-proxy] WARNING: DAKERA_ROOT_API_KEY is not set — forwarded requests will be unauthenticated.',
     );
@@ -23,6 +84,13 @@ function main() {
     ttlMs: config.sessionTtlMs,
     maxSessionsPerIp: config.maxSessionsPerIp,
     llmRateLimit: config.llmRateLimitPer10Min,
+    onExpire: (_sessionId, session) => {
+      if (!session.namespaces) return;
+      for (const ns of session.namespaces) {
+        deleteNamespace('_dakera_agent_' + ns);
+        console.log(`[sandbox-proxy] expired session — deleting namespace ${ns}`);
+      }
+    },
   });
 
   const sweep = setInterval(() => {
@@ -37,6 +105,8 @@ function main() {
       `[sandbox-proxy] v${config.version} listening on ${config.host}:${config.port} -> ${config.upstreamUrl} ` +
         `| rate=${config.rateLimitPerMin}/min cap=${config.memoryCapPerSession} ttl=${config.sessionTtlMs / 1000}s`,
     );
+    // BUG 6: Purge historical playground namespaces on startup
+    setTimeout(() => purgeStaleNamespaces(), 2000);
   });
 
   const shutdown = (sig) => {

docker/playground/proxy/proxy.test.js

@@ -227,6 +227,64 @@ test('sweep removes expired sessions', () => {
   assert.equal(store.size, 0);
 });
 
+test('sweep calls onExpire with tracked namespaces (DAK-6975)', () => {
+  let now = 0;
+  const expired = [];
+  const store = new SessionStore({
+    rateLimitPerMin: 10, memoryCap: 50, ttlMs: 100, maxSessionsPerIp: 0, now: () => now,
+    onExpire: (id, session) => { expired.push({ id, namespaces: [...session.namespaces] }); },
+  });
+  const res = store.resolve('pg_testexpire', '5.5.5.5');
+  assert.equal(res.ok, true);
+  store.trackNamespace(res.session, 'playground-demo-abc123');
+  store.trackNamespace(res.session, 'playground-demo-def456');
+  now = 200;
+  assert.equal(store.sweep(), 1);
+  assert.equal(expired.length, 1);
+  assert.equal(expired[0].id, 'pg_testexpire');
+  assert.deepStrictEqual(expired[0].namespaces.sort(), ['playground-demo-abc123', 'playground-demo-def456']);
+});
+
+test('resolve calls onExpire when session is expired on re-resolve (DAK-6975)', () => {
+  let now = 0;
+  const expired = [];
+  const store = new SessionStore({
+    rateLimitPerMin: 10, memoryCap: 50, ttlMs: 100, maxSessionsPerIp: 0, now: () => now,
+    onExpire: (id, session) => { expired.push(id); },
+  });
+  const res = store.resolve('pg_resolveexp', '6.6.6.6');
+  store.trackNamespace(res.session, 'playground-demo-aaa');
+  now = 200;
+  const res2 = store.resolve('pg_resolveexp', '6.6.6.6');
+  assert.equal(res2.ok, true);
+  assert.equal(expired.length, 1);
+  assert.equal(expired[0], 'pg_resolveexp');
+});
+
+test('trackNamespace adds to session.namespaces set (DAK-6975)', () => {
+  let now = 0;
+  const store = new SessionStore({ rateLimitPerMin: 10, memoryCap: 50, ttlMs: 100, maxSessionsPerIp: 0, now: () => now });
+  const res = store.resolve('pg_tracktest1', '7.7.7.7');
+  assert.equal(res.session.namespaces, undefined);
+  store.trackNamespace(res.session, 'ns-a');
+  store.trackNamespace(res.session, 'ns-b');
+  store.trackNamespace(res.session, 'ns-a');
+  assert.equal(res.session.namespaces.size, 2);
+});
+
+test('sweep does not call onExpire when no namespaces tracked (DAK-6975)', () => {
+  let now = 0;
+  let called = false;
+  const store = new SessionStore({
+    rateLimitPerMin: 10, memoryCap: 50, ttlMs: 100, maxSessionsPerIp: 0, now: () => now,
+    onExpire: () => { called = true; },
+  });
+  store.resolve('pg_nonamespace', '8.8.8.8');
+  now = 200;
+  store.sweep();
+  assert.equal(called, false);
+});
+
 // ---------------------------------------------------------------------------
 // unit: CORS (req #5)
 // ---------------------------------------------------------------------------

docker/playground/proxy/server.js

@@ -408,6 +408,7 @@ function createServer(config, store) {
       if (rewritten.clientAgentId !== null) {
         bodyBuf = rewritten.body;
         rewrite = { namespace: rewritten.namespace, restoreTo: rewritten.clientAgentId };
+        store.trackNamespace(resolved.session, rewritten.namespace);
       }
     }
 

docker/playground/proxy/sessions.js

@@ -39,7 +39,8 @@ class SessionStore {
     this.maxSessionsPerIp = opts.maxSessionsPerIp;
     this.llmRateLimit = opts.llmRateLimit !== undefined ? opts.llmRateLimit : 5;
     this.now = opts.now || Date.now;
-    /** @type {Map<string, {createdAt:number, calls:number[], memoryCount:number, ip:string, generated:boolean, llmCalls?:number[], llmSeeded?:boolean}>} */
+    this.onExpire = opts.onExpire || null;
+    /** @type {Map<string, {createdAt:number, calls:number[], memoryCount:number, ip:string, generated:boolean, llmCalls?:number[], llmSeeded?:boolean, namespaces?:Set<string>}>} */
     this.sessions = new Map();
   }
 
@@ -63,6 +64,9 @@ class SessionStore {
     let s = this.sessions.get(key);
     if (s && this._expired(s)) {
       // req #3: 30-min auto-expiry — drop stale state, start fresh.
+      if (this.onExpire && s.namespaces && s.namespaces.size > 0) {
+        try { this.onExpire(key, s); } catch (_) {}
+      }
       this.sessions.delete(key);
       s = undefined;
     }
@@ -151,11 +155,20 @@ class SessionStore {
     return { ok: true, remaining: this.llmRateLimit - session.llmCalls.length };
   }
 
-  /** Evict expired sessions; returns the number removed. */
+  /** Track a namespace used by this session (for cleanup on expiry). */
+  trackNamespace(session, namespace) {
+    if (!session.namespaces) session.namespaces = new Set();
+    session.namespaces.add(namespace);
+  }
+
+  /** Evict expired sessions; calls onExpire for engine cleanup. Returns count removed. */
   sweep() {
     let removed = 0;
     for (const [k, s] of this.sessions) {
       if (this._expired(s)) {
+        if (this.onExpire && s.namespaces && s.namespaces.size > 0) {
+          try { this.onExpire(k, s); } catch (_) {}
+        }
         this.sessions.delete(k);
         removed += 1;
       }