polly-ts-nestjs

NestJS module and decorators for Polly-TS, integrating resilience policies into your application architecture.

Installation

npm install polly-ts-core polly-ts-nestjs
# or
pnpm add polly-ts-core polly-ts-nestjs

Setup

register the global PollyModule with your policies.

// app.module.ts
import { Module } from '@nestjs/common';
import { PollyModule } from 'polly-ts-nestjs';
import { RetryPolicy } from 'polly-ts-core';

@Module({
  imports: [
    PollyModule.register({
      policies: [
        {
          name: 'exponentialRetry',
          useValue: new RetryPolicy({ maxAttempts: 5 }),
        },
      ],
    }),
  ],
})
export class AppModule {}

Usage

Use the @UsePolicy decorator to protect your Controller methods or Services (if wrapped via Interceptor manually).

import { Controller, Get } from '@nestjs/common';
import { UsePolicy } from 'polly-ts-nestjs';

@Controller('users')
export class UserController {
  @Get()
  @UsePolicy('exponentialRetry')
  async findAll() {
    // If this throws, it will be retried automatically
    return this.userService.findAll();
  }
}

Examples

PollyModule

@Module({
  imports: [
    PollyModule.register({
      policies: [{ name: 'retry', useValue: new RetryPolicy({ maxAttempts: 3 }) }],
    }),
  ],
})
export class AppModule {}

PollyInterceptor

providers: [{ provide: APP_INTERCEPTOR, useClass: PollyInterceptor }];

UsePolicy

@UsePolicy('retry')
async getData() {
  return this.service.fetch();
}

POLLY_POLICY_KEY

SetMetadata(POLLY_POLICY_KEY, 'retry');

API Reference

| API | Kind | Description | Example | | ------------------ | --------- | ----------------------------------------------------------------- | --------------------------------------------------------------------------- | | PollyModule | Class | NestJS module that registers policies and the global interceptor. | PollyModule.register({ policies: [{ name: 'retry', useValue: retry }] }); | | PollyInterceptor | Class | Interceptor that runs handlers inside the selected policy. | providers: [{ provide: APP_INTERCEPTOR, useClass: PollyInterceptor }] | | UsePolicy | Decorator | Attaches a policy name to a controller or method. | @UsePolicy('retry') | | POLLY_POLICY_KEY | Constant | Metadata key used to store the policy name. | SetMetadata(POLLY_POLICY_KEY, 'retry'); |