elastic-apm-nest

NestJS Elastic APM library.

Installation

npm i @student-coin/elastic-apm-nest --save

Usage

To your tsconfig.json add following lines:

"paths": {
      "elastic-apm-node": [
        "./node_modules/elastic-apm-nest/types/elastic-apm-node/index.d.ts"
      ]
    }

If your baseUrl in tsconfig.json is set to some directory, remember to change the path of elastic-apm-node

For example if your baseUrl: "./src" you need to replace . with ..

"paths": {
      "elastic-apm-node": [
        "../node_modules/elastic-apm-nest/types/elastic-apm-node/index.d.ts"
      ]
    }

import { APM_MIDDLEWARE, ApmErrorInterceptor, ApmHttpUserContextInterceptor, initializeAPMAgent } from 'elastic-apm-nest';

initializeAPMAgent({
  serviceName: '',
  secretToken: '',
  serverUrl: '',
});

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  const apmMiddleware = app.get(APM_MIDDLEWARE);
  const globalInterceptors = [
    app.get(ApmHttpUserContextInterceptor),
    app.get(ApmErrorInterceptor),
  ];

  app.useGlobalInterceptors(... globalInterceptors);

  app.use(apmMiddleware);
  await app.listen(3000);
}
bootstrap();

As NestJS is not allowing you to use some sort of ConfigService there you need to add to your repository dotenv package or something similar to pass configuration.

Adding ApmModule

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ApmModule } from 'elastic-apm-nest';

@Module({
  imports: [
    ApmModule.forRootAsync({
      useFactory: async () => {
        return {
          httpUserMapFunction: (req: any) => {
            return {
              id: req.user.id,
              username: req.user.username,
              email: req.user.email,
            };
          },
        };
      },
    }),
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

Module exports

ApmService - Wrapper for raw APM Agent instance APM_INSTANCE - Raw APM Agent instance APM_MIDDLEWARE - APM Raw Http middleware for express APM_OPTIONS - Current configuration for elastic-apm-nest

APM Decorator

There is possibility to use ApmCurrentTransaction to inject current transaction

  @HttpCode(200)
  @Get('/hello-world')
  getHelloWorld(
    @ApmCurrentTransaction()
    transaction: Transaction,
  ): string {
    return this.appService.getHello();
  }

Default ApmHttpUserContextInterceptor behavior

It won't set UserContext in transaction if httpUserMapFunction is not provided

Handling not supported methods

You can inject APM_INSTANCE which contains created APM instance via initializeAPMAgent function.

Testing locally

• Run npm run build:test
• Copy absolute path to generated .tgz file
• Run in other project npm install <path_to_.tgz_file>

ToDo

• [] Improve tests
• [] Add examples
• [] Add renovate
• Improve typings for elastic-apm