Nest NewRelic Observability Interceptor

observability.interceptor.ts

import {
  Injectable,
  NestInterceptor,
  ExecutionContext,
  CallHandler,
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { tap } from 'rxjs/operators';

// eslint-disable-next-line @typescript-eslint/no-var-requires
const newrelic = require('newrelic');

@Injectable()
export class ObservabilityInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    return newrelic.startWebTransaction(context.getHandler().name, () => {
      const transaction = this.getTransaction();

      // Add custom attributes here
      // newrelic.addCustomAttribute('someAttr', someAttr);

      return next.handle().pipe(
        tap(() => {
          this.endTransaction(transaction);
        }),
      );
    });
  }

  getTransaction(): any {
    return newrelic.getTransaction();
  }

  endTransaction(transaction: any): any {
    return transaction.end();
  }
}