feat: added service unavailable env variable and middleware

Author: Tarens2

src/common/config/env.validation.ts

@@ -1,6 +1,16 @@
 import { CronExpression } from '@nestjs/schedule';
 import { plainToClass, Transform } from 'class-transformer';
-import { IsEnum, IsNumber, IsString, IsOptional, validateSync, Min, IsArray, ArrayMinSize } from 'class-validator';
+import {
+  IsEnum,
+  IsNumber,
+  IsString,
+  IsOptional,
+  validateSync,
+  Min,
+  IsArray,
+  ArrayMinSize,
+  IsBoolean,
+} from 'class-validator';
 import { Environment, LogLevel, LogFormat } from './interfaces';
 
 const toNumber =
@@ -81,6 +91,11 @@ export class EnvironmentVariables {
   @IsNumber()
   @Transform(({ value }) => Number(value))
   CHAIN_ID: number = null;
+
+  @IsOptional()
+  @Transform(({ value }) => value === 'true')
+  @IsBoolean()
+  IS_SERVICE_UNAVAILABLE = false;
 }
 export const ENV_KEYS = Object.keys(new EnvironmentVariables());
 

src/common/middlewares/service-unavailable.middleware.ts

@@ -0,0 +1,25 @@
+import { ConfigService } from '@nestjs/config';
+import { HttpStatus } from '@nestjs/common';
+import { FastifyRequest, FastifyReply } from 'fastify';
+import { NestFastifyApplication } from '@nestjs/platform-fastify';
+
+const excludedRoutes = ['/api', '/health'];
+
+export const setupServiceUnavailableMiddleware = (app: NestFastifyApplication, configService: ConfigService) => {
+  app
+    .getHttpAdapter()
+    .getInstance()
+    .addHook('onRequest', async (req: FastifyRequest, res: FastifyReply) => {
+      if (excludedRoutes.some((route) => req.url.startsWith(route))) {
+        return;
+      }
+      const isMaintenance = configService.get('IS_SERVICE_UNAVAILABLE');
+
+      if (isMaintenance) {
+        res.code(HttpStatus.SERVICE_UNAVAILABLE).send({
+          statusCode: HttpStatus.SERVICE_UNAVAILABLE,
+          message: 'Service is temporarily unavailable. Please try again later.',
+        });
+      }
+    });
+};

src/events/rewards/rewards.service.ts

@@ -43,6 +43,10 @@ export class RewardsService {
    * Initializes the job
    */
   public async initialize(): Promise<void> {
+    if (this.configService.get('IS_SERVICE_UNAVAILABLE')) {
+      return;
+    }
+
     await this.updateRewards();
 
     // getting total rewards per frame starts from TokenRebased event because it contains

src/jobs/contract-config/contract-config.service.ts

@@ -32,6 +32,10 @@ export class ContractConfigService {
    * Initializes the job
    */
   public async initialize(): Promise<void> {
+    if (this.configService.get('IS_SERVICE_UNAVAILABLE')) {
+      return;
+    }
+
     await this.updateContractConfig();
 
     const cronTime = this.configService.get('JOB_INTERVAL_CONTRACT_CONFIG');

src/jobs/queue-info/queue-info.service.ts

@@ -30,6 +30,10 @@ export class QueueInfoService {
    * Initializes the job
    */
   public async initialize(): Promise<void> {
+    if (this.configService.get('IS_SERVICE_UNAVAILABLE')) {
+      return;
+    }
+
     const cronTime = this.configService.get('JOB_INTERVAL_QUEUE_INFO');
     this.job = new CronJob(cronTime, () => this.updateQueueInfo());
     await this.updateQueueInfo();

src/jobs/validators/validators.service.ts

@@ -44,6 +44,10 @@ export class ValidatorsService {
    * Initializes the job
    */
   public async initialize(): Promise<void> {
+    if (this.configService.get('IS_SERVICE_UNAVAILABLE')) {
+      return;
+    }
+
     await this.validatorsCacheService.initializeFromCache();
 
     const envCronTime = this.configService.get('JOB_INTERVAL_VALIDATORS');

src/main.ts

@@ -9,6 +9,7 @@ import { ConfigService } from 'common/config';
 import { AppModule, APP_DESCRIPTION, APP_NAME, APP_VERSION } from 'app';
 import { satanizer, commonPatterns } from '@lidofinance/satanizer';
 import { useContainer } from 'class-validator';
+import { setupServiceUnavailableMiddleware } from './common/middlewares/service-unavailable.middleware';
 
 async function bootstrap() {
   const app = await NestFactory.create<NestFastifyApplication>(AppModule, new FastifyAdapter({ trustProxy: true }), {
@@ -77,6 +78,8 @@ async function bootstrap() {
   const swaggerDocument = SwaggerModule.createDocument(app, swaggerConfig);
   SwaggerModule.setup(SWAGGER_URL, app, swaggerDocument);
 
+  setupServiceUnavailableMiddleware(app, configService);
+
   // app
   await app.listen(appPort, '0.0.0.0');
 }