add lock to image resize

package.json

@@ -21,6 +21,7 @@
     "test:e2e": "jest --config ./test/jest-e2e.json"
   },
   "dependencies": {
+    "@nestjs-modules/ioredis": "^1.0.1",
     "@nestjs/axios": "^0.0.4",
     "@nestjs/common": "^8.0.0",
     "@nestjs/config": "^1.1.6",
@@ -31,9 +32,11 @@
     "@xzeldon/imagemagick-native": "^1.9.5",
     "class-transformer": "^0.4.0",
     "class-validator": "^0.13.2",
+    "ioredis": "^4.28.5",
     "lodash": "^4.17.21",
     "pg": "^8.7.1",
     "pg-native": "^3.0.0",
+    "redlock": "^5.0.0-beta.2",
     "reflect-metadata": "^0.1.13",
     "rimraf": "^3.0.2",
     "rxjs": "^7.2.0",

src/app.module.ts

@@ -7,6 +7,8 @@ import { HttpModule } from '@nestjs/axios';
 import { AvatarApiService } from './avatar-api/avatar-api.service';
 import { ImageService } from './image/image.service';
 import { Avatar } from './entities/Avatar.entity';
+import { LockService } from './lock/lock.service';
+import { RedisModule } from '@nestjs-modules/ioredis';
 
 @Module({
   imports: [
@@ -31,8 +33,16 @@ import { Avatar } from './entities/Avatar.entity';
         };
       },
     }),
+    RedisModule.forRootAsync({
+      inject: [ConfigService],
+      useFactory: async (config: ConfigService) => ({
+        config: {
+          url: config.get('REDIS_URL'),
+        },
+      }),
+    }),
   ],
   controllers: [AppController],
-  providers: [AppService, AvatarApiService, ImageService],
+  providers: [AppService, AvatarApiService, ImageService, LockService],
 })
 export class AppModule {}

src/app.service.ts

@@ -4,6 +4,7 @@ import { Injectable, ConsoleLogger } from '@nestjs/common';
 import { ImageService } from './image/image.service';
 import { AvatarApiService } from './avatar-api/avatar-api.service';
 import { Avatar } from './entities/Avatar.entity';
+import { LockService } from './lock/lock.service';
 
 @Injectable()
 export class AppService extends ConsoleLogger {
@@ -12,6 +13,7 @@ export class AppService extends ConsoleLogger {
     private db: Connection,
     private image: ImageService,
     private avatarApi: AvatarApiService,
+    private lockService: LockService,
   ) {
     super('app');
   }
@@ -37,30 +39,39 @@ export class AppService extends ConsoleLogger {
       return existingAvatar.toBuffer();
     }
     this.log(`Resizing ${url} to ${size}`);
-    let originalAvatarBuffer: Buffer;
-    const originalAvatar = await this.db.getRepository(Avatar).findOne({
-      where: {
-        url,
-        size: 0,
+    return this.lockService.using(
+      [`avatar_${url}_${size}`],
+      10000,
+      async () => {
+        let originalAvatarBuffer: Buffer;
+        const originalAvatar = await this.db.getRepository(Avatar).findOne({
+          where: {
+            url,
+            size: 0,
+          },
+          select: ['content'],
+        });
+        if (originalAvatar) {
+          originalAvatarBuffer = originalAvatar.toBuffer();
+        } else {
+          originalAvatarBuffer = await this.avatarApi.downloadAvatar(url);
+          try {
+            await this.saveAvatar(url, 0, originalAvatarBuffer);
+          } catch (e) {
+            this.error(`Fail to save original avatar: ${e.message}`);
+          }
+        }
+        const avatarBuffer = await this.image.resize(
+          originalAvatarBuffer,
+          size,
+        );
+        try {
+          await this.saveAvatar(url, size, avatarBuffer);
+        } catch (e) {
+          this.error(`Fail to save avatar: ${e.message}`);
+        }
+        return avatarBuffer;
       },
-      select: ['content'],
-    });
-    if (originalAvatar) {
-      originalAvatarBuffer = originalAvatar.toBuffer();
-    } else {
-      originalAvatarBuffer = await this.avatarApi.downloadAvatar(url);
-      try {
-        await this.saveAvatar(url, 0, originalAvatarBuffer);
-      } catch (e) {
-        this.error(`Fail to save original avatar: ${e.message}`);
-      }
-    }
-    const avatarBuffer = await this.image.resize(originalAvatarBuffer, size);
-    try {
-      await this.saveAvatar(url, size, avatarBuffer);
-    } catch (e) {
-      this.error(`Fail to save avatar: ${e.message}`);
-    }
-    return avatarBuffer;
+    );
   }
 }

src/lock/lock.service.spec.ts

+import { Test, TestingModule } from '@nestjs/testing';
+import { LockService } from './lock.service';
+
+describe('LockService', () => {
+  let service: LockService;
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [LockService],
+    }).compile();
+
+    service = module.get<LockService>(LockService);
+  });
+
+  it('should be defined', () => {
+    expect(service).toBeDefined();
+  });
+});

src/lock/lock.service.ts

+import { InjectRedis, Redis } from '@nestjs-modules/ioredis';
+import { Injectable } from '@nestjs/common';
+import Redlock from 'redlock';
+
+@Injectable()
+export class LockService extends Redlock {
+  constructor(@InjectRedis() private readonly redis: Redis) {
+    super([redis]);
+  }
+}