feat: Add game activity status (Experimental)

server/src/db/database.ts

@@ -14,7 +14,8 @@ import {
   JoinRequestEntity,
   ServerMembershipEntity,
   ServerInviteEntity,
-  ServerBanEntity
+  ServerBanEntity,
+  GameMatchMissEntity
 } from '../entities';
 import { serverMigrations } from '../migrations';
 import {
@@ -48,8 +49,25 @@ const DB_BACKUP = DB_FILE + '.bak';
 const DATA_DIR = path.dirname(DB_FILE);
 // SQLite files start with this 16-byte header string.
 const SQLITE_MAGIC = 'SQLite format 3\0';
+const SAVE_RETRY_DELAYS_MS = [25, 75, 150, 300, 600];
+const RETRYABLE_SAVE_ERROR_CODES = new Set(['EPERM', 'EACCES', 'EBUSY']);
 
 let applicationDataSource: DataSource | undefined;
+let saveQueue: Promise<void> = Promise.resolve();
+
+function wait(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+function isRetryableSaveError(error: unknown): boolean {
+  if (!error || typeof error !== 'object') {
+    return false;
+  }
+
+  const code = (error as NodeJS.ErrnoException).code;
+
+  return typeof code === 'string' && RETRYABLE_SAVE_ERROR_CODES.has(code);
+}
 
 function restoreFromBackup(reason: string): Uint8Array | undefined {
   if (!fs.existsSync(DB_BACKUP)) {
@@ -159,18 +177,47 @@ function resolveSqlJsConfig(): { locateFile: (file: string) => string } {
  * then rename it over the real file. rename() is atomic on the same
  * filesystem, so a crash mid-write can never leave a half-written DB.
  */
-async function atomicSave(data: Uint8Array): Promise<void> {
+async function replaceDatabaseFile(tmpPath: string): Promise<void> {
+  for (let attempt = 0; ; attempt++) {
+    try {
+      await fsp.rename(tmpPath, DB_FILE);
+      return;
+    } catch (error) {
+      const delay = SAVE_RETRY_DELAYS_MS[attempt];
+
+      if (!isRetryableSaveError(error) || delay === undefined) {
+        throw error;
+      }
+
+      await wait(delay);
+    }
+  }
+}
+
+async function writeDatabaseSnapshot(snapshot: Buffer): Promise<void> {
   const tmpPath = DB_FILE + '.tmp-' + randomBytes(6).toString('hex');
 
   try {
-    await fsp.writeFile(tmpPath, Buffer.from(data));
-    await fsp.rename(tmpPath, DB_FILE);
+    await fsp.writeFile(tmpPath, snapshot);
+    await replaceDatabaseFile(tmpPath);
   } catch (err) {
     await fsp.unlink(tmpPath).catch(() => {});
     throw err;
   }
 }
 
+async function atomicSave(data: Uint8Array): Promise<void> {
+  const snapshot = Buffer.from(data);
+  const saveTask = saveQueue.then(
+    () => writeDatabaseSnapshot(snapshot),
+    () => writeDatabaseSnapshot(snapshot)
+  );
+
+  saveQueue = saveTask.catch(() => {});
+
+  return saveTask;
+}
+
 export function getDataSource(): DataSource {
   if (!applicationDataSource?.isInitialized) {
     throw new Error('DataSource not initialised');
@@ -202,7 +249,8 @@ export async function initDatabase(): Promise<void> {
         JoinRequestEntity,
         ServerMembershipEntity,
         ServerInviteEntity,
-        ServerBanEntity
+        ServerBanEntity,
+        GameMatchMissEntity
       ],
       migrations: serverMigrations,
       synchronize: process.env.DB_SYNCHRONIZE === 'true',