Tracing a NestJS Application

Recap.Dev provides two levels of tracing: basic tracing and function-level tracing.

Basic tracing collects request, response and error information, logs, and provides a timeline of external resource access (databases, HTTP endpoints, external services) of your unit (basically, endpoint or handler).

Function-level tracing also adds timings of the individual function calls to the timeline.

Setting up a Basic Tracing#

1. Install the Recap.Dev Client Library#

yarn add @recap.dev/client

npm i --save @recap.dev/client

2. Enable the NestJS Tracing#

Call the initNestJsTracing function before creating your NestJS app.

import { initNestJsTracing } from '@recap.dev/client';
import { NestFactory } from '@nestjs/core';

import { AppModule } from './app.module';

initNestJsTracing();

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

  await app.listen(3000);
}

bootstrap();

You may also pass these options to the initNestJsTracing function:

captureLogs - Enables or disables capture of logs from global console object. Defaults to true.
disableAutomaticUnitNames - Disables default environment-injectable.methodName unit names. Defaults to false.
ignoreUnnamedUnits - Ignore traces without a unit name. Useful if you want to ignore requests to static assets or only trace particular modules. Defaults to true.
assignUnitName - Defines a unit name for a trace. The default strategy creates a unit name using a first injectable method appearing in the chain and an environment. An example of the unit name generated is local-CatFactsResolver.catFacts

3. Wrap NestJS Modules to Trace Them#

Wrap a NestJS module with wrapNestJsModule function exported from the @recap.dev/client to trace it with Recap.Dev.

import { initNestJsTracing, wrapNestJsModule } from '@recap.dev/client';
import { NestFactory } from '@nestjs/core';

import { AppModule } from './app.module';

initNestJsTracing();

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

  await app.listen(3000);
}

bootstrap();

4. Set the `RECAP_DEV_SYNC_ENDPOINT` environment variable to point at your Recap.Dev server's sync endpoint, for example:#

http://recap-dev.company.com:8080/traces

Check the complete source code of an example NestJS project traced with Recap.Dev here.

Setting up a Function-level Tracing#

Click here to learn how to set up the function-level tracing for your application.