Amplication NestJS Logger Module

The @amplication/util/nestjs/logging is our official logger module. This library leverage, under the hood, the framework-agnostic amplication logging library @amplication/util/logging.

All nestjs services at Amplication must use this library to ensure consistent logging. This will enable us to trace and observe our systems reliably.

Getting started

Consume the module

In your microservices, import the logger module and consume it in your root module.

// app.module.ts

import { AmplicationLoggerModule } from '@amplication/util/nestjs/logging';

@Module({
  imports: [
    //...
    AmplicationLoggerModule.forRoot({
      component: SERVICE_NAME,
    }),
    //...
  ],
})
export class AppModule implements // ....

The minimum log level can be configured also with the LOG_LEVEL environment variable, instead of the logLevel: LogLevel.Warn, to one of the following values:

• debug
• info
• warn
• error

Usage

You can import the logger via dependency injection.

// example.service.ts

import {
  AmplicationLogger,
} from "@amplication/util/nestjs/logging";

@Injectable()
export class ExampleService {
  constructor(
    @Inject(AmplicationLogger)
    private readonly logger: AmplicationLogger
  ) {}

  someMethod() {
    this.logger.debug("This is a debug log", { some: "context" });
    this.logger.info("This is a info log", { some: "context" });
    this.logger.warn("This is a warn log", { some: "context" });
    this.logger.error("This is a error log", { some: "context" });
  }
}

Testing utils

A mocked provider can be used in unit tests. The following example explain how to use it

/// myservice.spec.ts

import { MockedAmplicationLoggerProvider } from "@amplication/util/nestjs/logging/test-utils";

//...
 const module: TestingModule = await Test.createTestingModule({
      providers: [
        // ... 
        MockedAmplicationLoggerProvider,
        // ...
      ]
      //...
 }).compile();
//...