nestjs-context-tracer

Trace each http context of your nest.js application. This enable to trace http request by unique id. Each request has unique Id and You can get id on controller, service, dao, anywhere.

Usage

Configuration

Add module and set middleware

• configure middleware for every http method and path

example

• app.module.ts

import { AsyncTraceIdMiddleware, AsyncTraceModule } from 'nestjs-context-tracer';

@Module({
  imports: [ AsyncTraceModule.forRoot() ],
  controllers: [AppController],
  ...
})
export class AppModule implements NestModule {
    configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(AsyncTraceIdMiddleware)
      .forRoutes({ path: '*', method: RequestMethod.ALL });
  }
}

Get Trace Id

Use getTraceId method of AsyncContext

asyncContext.getTraceId(): string | null

example

• app.controller.ts

import { AsyncContext } from 'nestjs-context-tracer';

@Controller()
export class AppController {
  constructor(
    private readonly asyncContext: AsyncContext
  ) {}

  @Get()
  getHello(): string {
    console.log('begin trace-id:', this.asyncContext.getTraceId());
    ....
  }

You can see unique begin trace-id output by each http request. trace-id is generated by uuid v4.

Set & Get For Custom data

You can set any data and get by this library.

asyncContext.set(key, value): void

Arguments:

• key string
• value unknown

example

asyncContext.set('role', 'ADMIN');

asyncContext.get(key): unknown

Arguments:

• key string

example

const userRole = asyncContext.get('role');

Important Note

Performance Issue

This library based on AsyncLocalStorage AsyncLocalStorage tend to drop application performance. Drop rate is different by node.js version. It recommends to use v16.2 or above version. If you want to see more information see this issue.

Context loss

If your code is based on callback, not promsie, you must read this document.

Do not use 0.2.0 or below

That version has critical bug. some http request share storeage.

This library inspired by https://github.com/nestjs/nest/pull/1407

License

MIT