Sleeping rooms stay asleep across a restart

Idle rooms already went back to their ledgers, but a boot replayed
every ledger before the first sweep could put them to bed again — most
of a restart's fifteen seconds spent rebuilding games nobody was at.
A room put to sleep now leaves a stub beside the ledgers, with the
ledger's size at that moment; at boot a stub whose size still matches
answers for the room and the ledger stays unreplayed. Replayed rooms
take their eviction clock from the ledger's last line, so the first
sweep after a boot writes the stubs for everything long idle.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jm2auWk6RP71CjaAb4FMoG

packages/server/src/rooms.ts

@@ -22,7 +22,7 @@ import {
   type PlayerId,
   CURRENT_RULES_REV,
 } from "@wizwar/engine";
-import { appendLine, archiveRoomFile, countRoomFiles, ensureDataDir, readAllRooms, readRoom, roomFileExists, type RoomLine } from "./store";
+import { appendLine, archiveRoomFile, countRoomFiles, ensureDataDir, ledgerStat, listRoomIds, readRoom, readStubFile, roomFileExists, writeStubFile, type RoomLine } from "./store";
 import { recordRoom } from "./stats";
 
 export interface LoggedCommand {
@@ -159,9 +159,16 @@ export function evictIdleRooms(hasSockets: (roomId: string) => boolean): number
     const idle = now - (room.touchedAt ?? now);
     const allowance = room.state?.phase === "finished" ? FINISHED_MS : IDLE_MS;
     if (idle < allowance) continue;
-    sleepingStubs.set(id, stubOf(room));
+    const stub = stubOf(room);
+    sleepingStubs.set(id, stub);
     rooms.delete(id);
     evicted++;
+    try {
+      const stat = ledgerStat(id);
+      if (stat) writeStubFile(id, stat.bytes, { ...stub, tokens: Object.fromEntries(stub.tokens) });
+    } catch (e) {
+      console.error(`could not write stub for ${id}:`, e);
+    }
   }
   return evicted;
 }
@@ -176,6 +183,8 @@ interface RoomStub {
   base: Omit<GameSummary, "name" | "yourTurn" | "attention">;
 }
 const sleepingStubs = new Map<string, RoomStub>();
+/** A stub as it rests on disk — the token map spelled as an object. */
+type StoredStub = Omit<RoomStub, "tokens"> & { tokens: Record<PlayerId, string> };
 
 function stubOf(room: Room): RoomStub {
   const { active, turnHolder, waitKind } = turnFacts(room.state);
@@ -775,14 +784,29 @@ function rebuildRoom(id: string, lines: RoomLine[]): Room | null {
   return room;
 }
 
-/** Rebuild every persisted room by replaying its file. */
+/** Bring the rooms back after a restart. A room whose stub still matches
+ * its ledger sleeps on, answering the games ledger from the stub; the
+ * rest are replayed, with the eviction clock set to their last line so
+ * the first sweep puts the long-idle ones back to bed. */
 export function loadPersistedRooms(): void {
   ensureDataDir();
   let restored = 0;
-  for (const [id, lines] of readAllRooms()) {
+  let asleep = 0;
+  for (const id of listRoomIds()) {
+    const stat = ledgerStat(id);
+    if (!stat) continue;
+    const stored = readStubFile<StoredStub>(id);
+    if (stored && stored.bytes === stat.bytes) {
+      sleepingStubs.set(id, { ...stored.stub, tokens: new Map(Object.entries(stored.stub.tokens)) });
+      asleep++;
+      continue;
+    }
+    const lines = readRoom(id);
+    if (!lines) continue;
     try {
       const room = rebuildRoom(id, lines);
       if (!room) continue;
+      room.touchedAt = stat.mtimeMs;
       rooms.set(id, room);
       recordRoom(room);
       restored++;
@@ -790,5 +814,5 @@ export function loadPersistedRooms(): void {
       console.error(`could not restore room ${id}:`, e);
     }
   }
-  if (restored > 0) console.log(`restored ${restored} room(s) from disk`);
+  if (restored + asleep > 0) console.log(`restored ${restored} room(s) from disk, ${asleep} left sleeping`);
 }

packages/server/src/store.ts

@@ -3,7 +3,7 @@
 // command. Because the engine is deterministic, replaying a file rebuilds
 // the exact game state — server restarts lose nothing.
 
-import { appendFileSync, existsSync, mkdirSync, readdirSync, readFileSync, renameSync } from "node:fs";
+import { appendFileSync, existsSync, mkdirSync, readdirSync, readFileSync, renameSync, statSync, writeFileSync } from "node:fs";
 import { join } from "node:path";
 
 export interface RoomMetaLine {
@@ -128,24 +128,48 @@ export function countRoomFiles(): number {
   return readdirSync(DATA_DIR).filter((f) => f.endsWith(".jsonl")).length;
 }
 
-/** Read every persisted room's lines, keyed by room id. */
-export function readAllRooms(): Map<string, RoomLine[]> {
+/** Every room with a ledger on disk. */
+export function listRoomIds(): string[] {
   ensureDataDir();
-  const rooms = new Map<string, RoomLine[]>();
-  for (const file of readdirSync(DATA_DIR)) {
-    if (!file.endsWith(".jsonl")) continue;
-    const id = file.slice(0, -".jsonl".length);
+  return readdirSync(DATA_DIR).filter((f) => f.endsWith(".jsonl")).map((f) => f.slice(0, -".jsonl".length));
+}
+
+/** A ledger's size and the moment of its last line. */
+export function ledgerStat(roomId: string): { bytes: number; mtimeMs: number } | null {
+  if (!safeRoomId(roomId)) return null;
+  const file = fileFor(roomId);
+  if (!existsSync(file)) return null;
+  const st = statSync(file);
+  return { bytes: st.size, mtimeMs: st.mtimeMs };
+}
+
+// --- Stubs of sleeping rooms. ---------------------------------------------
+// A room put to sleep leaves a stub beside the ledgers: what the games
+// ledger needs to answer for it, and the ledger's size at that moment. A
+// ledger only ever grows, so at boot a stub whose size still matches is
+// the room's whole truth and the room stays asleep, unreplayed.
+
+const stubDir = () => join(DATA_DIR, "..", "stubs");
+const stubFor = (roomId: string) => join(stubDir(), `${roomId}.json`);
+
+export function readStubFile<T>(roomId: string): { bytes: number; stub: T } | null {
+  if (!safeRoomId(roomId)) return null;
+  const file = stubFor(roomId);
+  if (!existsSync(file)) return null;
   try {
-      const lines = readFileSync(join(DATA_DIR, file), "utf8")
-        .split("\n")
-        .filter((l) => l.trim().length > 0)
-        .map((l) => JSON.parse(l) as RoomLine);
-      if (lines.length > 0 && lines[0]!.kind === "meta") rooms.set(id, lines);
+    const parsed = JSON.parse(readFileSync(file, "utf8")) as { bytes: number; stub: T };
+    return typeof parsed.bytes === "number" && parsed.stub ? parsed : null;
   } catch (e) {
-      console.error(`skipping unreadable room file ${file}:`, e);
+    console.error(`unreadable stub file ${roomId}:`, e);
+    return null;
   }
-  }
-  return rooms;
+}
+
+export function writeStubFile(roomId: string, bytes: number, stub: unknown): void {
+  const file = stubFor(roomId);
+  mkdirSync(stubDir(), { recursive: true });
+  writeFileSync(file + ".tmp", JSON.stringify({ bytes, stub }), "utf8");
+  renameSync(file + ".tmp", file);
 }
 
 /** Player surprise reports and the wizards' replies share one JSONL file