fix(server): handle expired lock re-release & external locker injection (#6145)

packages/backend/server/src/fundamentals/mutex/index.ts

@@ -6,7 +6,7 @@ import { MutexService } from './mutex';
 @Global()
 @Module({
   providers: [MutexService, Locker],
-  exports: [MutexService, Locker],
+  exports: [MutexService],
 })
 export class MutexModule {}
 

packages/backend/server/src/fundamentals/mutex/mutex.ts

@@ -14,11 +14,21 @@ export const MUTEX_WAIT = 100;
 @Injectable({ scope: Scope.REQUEST })
 export class MutexService {
   protected logger = new Logger(MutexService.name);
+  private readonly locker: Locker;
 
   constructor(
     @Inject(CONTEXT) private readonly context: GraphqlContext,
     private readonly ref: ModuleRef
-  ) {}
+  ) {
+    // nestjs will always find and injecting the locker from local module
+    // so the RedisLocker implemented by the plugin mechanism will not be able to overwrite the internal locker
+    // we need to use find and get the locker from the `ModuleRef` manually
+    //
+    // NOTE: when a `constructor` execute in normal service, the Locker module we expect may not have been initialized
+    //       but in the Service with `Scope.REQUEST`, we will create a separate Service instance for each request
+    //       at this time, all modules have been initialized, so we able to get the correct Locker instance in `constructor`
+    this.locker = this.ref.get(Locker, { strict: false });
+  }
 
   protected getId() {
     let id = this.context.req.headers['x-transaction-id'] as string;
@@ -55,10 +65,7 @@ export class MutexService {
   async lock(key: string) {
     try {
       return await retryable(
-        () => {
-          const locker = this.ref.get(Locker, { strict: false });
-          return locker.lock(this.getId(), key);
-        },
+        () => this.locker.lock(this.getId(), key),
         MUTEX_RETRY,
         MUTEX_WAIT
       );