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NestJS-Pino

✨✨✨ Platform agnostic logger for NestJS based on Pino with REQUEST CONTEXT IN EVERY LOG ✨✨✨

---

This is documentation for v2+ which works with NestJS 8+.
Please see documentation for the previous major version which works with NestJS < 8 here.

---

Install

1npm i nestjs-pino pino-http

Example

Firstly, import module with LoggerModule.forRoot(...) or LoggerModule.forRootAsync(...) only once in root module (check out module configuration docs below):

1import { LoggerModule } from 'nestjs-pino';
2
3@Module({
4  imports: [LoggerModule.forRoot()],
5})
6class AppModule {}

Secondly, set up app logger:

1import { Logger } from 'nestjs-pino';
2
3const app = await NestFactory.create(AppModule, { bufferLogs: true });
4app.useLogger(app.get(Logger));

Now you can use one of two loggers:

1// NestJS standard built-in logger.
2// Logs will be produced by pino internally
3import { Logger } from '@nestjs/common';
4
5export class MyService {
6  private readonly logger = new Logger(MyService.name);
7  foo() {
8    // All logger methods have args format the same as pino, but pino methods
9    // `trace` and `info` are mapped to `verbose` and `log` to satisfy
10    // `LoggerService` interface of NestJS:
11    this.logger.verbose({ foo: 'bar' }, 'baz %s', 'qux');
12    this.logger.debug('foo %s %o', 'bar', { baz: 'qux' });
13    this.logger.log('foo');
14  }
15}

Usage of the standard logger is recommended and idiomatic for NestJS. But there is one more option to use:

1import { PinoLogger, InjectPinoLogger } from 'nestjs-pino';
2
3export class MyService {
4  constructor(
5    private readonly logger: PinoLogger
6  ) {
7    // Optionally you can set context for logger in constructor or ...
8    this.logger.setContext(MyService.name);
9  }
10
11  constructor(
12    // ... set context via special decorator
13    @InjectPinoLogger(MyService.name)
14    private readonly logger: PinoLogger
15  ) {}
16
17  foo() {
18    // PinoLogger has same methods as pino instance
19    this.logger.trace({ foo: 'bar' }, 'baz %s', 'qux');
20    this.logger.debug('foo %s %o', 'bar', { baz: 'qux' });
21    this.logger.info('foo');
22  }
23}

Output:

1// Logs by app itself
2{"level":30,"time":1629823318326,"pid":14727,"hostname":"my-host","context":"NestFactory","msg":"Starting Nest application..."}
3{"level":30,"time":1629823318326,"pid":14727,"hostname":"my-host","context":"InstanceLoader","msg":"LoggerModule dependencies initialized"}
4{"level":30,"time":1629823318327,"pid":14727,"hostname":"my-host","context":"InstanceLoader","msg":"AppModule dependencies initialized"}
5{"level":30,"time":1629823318327,"pid":14727,"hostname":"my-host","context":"RoutesResolver","msg":"AppController {/}:"}
6{"level":30,"time":1629823318327,"pid":14727,"hostname":"my-host","context":"RouterExplorer","msg":"Mapped {/, GET} route"}
7{"level":30,"time":1629823318327,"pid":14727,"hostname":"my-host","context":"NestApplication","msg":"Nest application successfully started"}
8
9// Logs by injected Logger and PinoLogger in Services/Controllers. Every log
10// has it's request data and unique `req.id` (by default id is unique per
11// process, but you can set function to generate it from request context and
12// for example pass here incoming `X-Request-ID` header or generate UUID)
13{"level":10,"time":1629823792023,"pid":15067,"hostname":"my-host","req":{"id":1,"method":"GET","url":"/","query":{},"params":{"0":""},"headers":{"host":"localhost:3000","user-agent":"curl/7.64.1","accept":"*/*"},"remoteAddress":"::1","remotePort":63822},"context":"MyService","foo":"bar","msg":"baz qux"}
14{"level":20,"time":1629823792023,"pid":15067,"hostname":"my-host","req":{"id":1,"method":"GET","url":"/","query":{},"params":{"0":""},"headers":{"host":"localhost:3000","user-agent":"curl/7.64.1","accept":"*/*"},"remoteAddress":"::1","remotePort":63822},"context":"MyService","msg":"foo bar {\"baz\":\"qux\"}"}
15{"level":30,"time":1629823792023,"pid":15067,"hostname":"my-host","req":{"id":1,"method":"GET","url":"/","query":{},"params":{"0":""},"headers":{"host":"localhost:3000","user-agent":"curl/7.64.1","accept":"*/*"},"remoteAddress":"::1","remotePort":63822},"context":"MyService","msg":"foo"}
16
17// Automatic logs of every request/response
18{"level":30,"time":1629823792029,"pid":15067,"hostname":"my-host","req":{"id":1,"method":"GET","url":"/","query":{},"params":{"0":""},"headers":{"host":"localhost:3000","user-agent":"curl/7.64.1","accept":"*/*"},"remoteAddress":"::1","remotePort":63822},"res":{"statusCode":200,"headers":{"x-powered-by":"Express","content-type":"text/html; charset=utf-8","content-length":"12","etag":"W/\"c-Lve95gjOVATpfV8EL5X4nxwjKHE\""}},"responseTime":7,"msg":"request completed"}

Comparison with others

There are other Nestjs loggers. Key purposes of this module are:

• to be idiomatic NestJS logger
• to log in JSON format (thanks to pino - super fast logger) why you should use JSON
• to log every request/response automatically (thanks to pino-http)
• to bind request data to the logs automatically from any service on any application layer without passing request context (thanks to AsyncLocalStorage)
• to have another alternative logger with same API as pino instance (PinoLogger) for experienced pino users to make more comfortable usage.

Logger	Nest App logger	Logger service	Auto-bind request data to logs
nest-winston	+	+	-
nestjs-pino-logger	+	+	-
nestjs-pino	+	+	+

Configuration

Zero configuration

Just import LoggerModule to your module:

1import { LoggerModule } from 'nestjs-pino';
2
3@Module({
4  imports: [LoggerModule.forRoot()],
5  ...
6})
7class MyModule {}

Configuration params

The following interface is using for the configuration:

1interface Params {
2  /**
3   * Optional parameters for `pino-http` module
4   * @see https://github.com/pinojs/pino-http#api
5   */
6  pinoHttp?:
7    | pinoHttp.Options
8    | DestinationStream
9    | [pinoHttp.Options, DestinationStream];
10
11  /**
12   * Optional parameter for routing. It should implement interface of
13   * parameters of NestJS built-in `MiddlewareConfigProxy['forRoutes']`.
14   * @see https://docs.nestjs.com/middleware#applying-middleware
15   * It can be used for both disabling automatic req/res logs (see above) and
16   * removing request context from following logs. It works for all requests by
17   * default. If you only need to turn off the automatic request/response
18   * logging for some specific (or all) routes but keep request context for app
19   * logs use `pinoHttp.autoLogging` field.
20   */
21  forRoutes?: Parameters<MiddlewareConfigProxy['forRoutes']>;
22
23  /**
24   * Optional parameter for routing. It should implement interface of
25   * parameters of NestJS built-in `MiddlewareConfigProxy['exclude']`.
26   * @see https://docs.nestjs.com/middleware#applying-middleware
27   * It can be used for both disabling automatic req/res logs (see above) and
28   * removing request context from following logs. It works for all requests by
29   * default. If you only need to turn off the automatic request/response
30   * logging for some specific (or all) routes but keep request context for app
31   * logs use `pinoHttp.autoLogging` field.
32   */
33  exclude?: Parameters<MiddlewareConfigProxy['exclude']>;
34
35  /**
36   * Optional parameter to skip pino configuration in case you are using
37   * FastifyAdapter, and already configure logger in adapter's config. The Pros
38   * and cons of this approach are described in the FAQ section of the
39   * documentation:
40   * @see https://github.com/iamolegga/nestjs-pino#faq.
41   */
42  useExisting?: true;
43
44  /**
45   * Optional parameter to change property name `context` in resulted logs,
46   * so logs will be like:
47   * {"level":30, ... "RENAME_CONTEXT_VALUE_HERE":"AppController" }
48   */
49  renameContext?: string;
50}

Synchronous configuration

Use LoggerModule.forRoot method with argument of Params interface:

1import { LoggerModule } from 'nestjs-pino';
2
3@Module({
4  imports: [
5    LoggerModule.forRoot({
6      pinoHttp: [
7        {
8          name: 'add some name to every JSON line',
9          level: process.env.NODE_ENV !== 'production' ? 'debug' : 'info',
10          // install 'pino-pretty' package in order to use the following option
11          transport: process.env.NODE_ENV !== 'production'
12            ? { target: 'pino-pretty' }
13            : undefined,
14
15
16          // and all the other fields of:
17          // - https://github.com/pinojs/pino-http#api
18          // - https://github.com/pinojs/pino/blob/HEAD/docs/api.md#options-object
19
20
21        },
22        someWritableStream
23      ],
24      forRoutes: [MyController],
25      exclude: [{ method: RequestMethod.ALL, path: 'check' }]
26    })
27  ],
28  ...
29})
30class MyModule {}

Asynchronous configuration

With LoggerModule.forRootAsync you can, for example, import your ConfigModule and inject ConfigService to use it in useFactory method.

useFactory should return object with Params interface or undefined

Here's an example:

1import { LoggerModule } from 'nestjs-pino';
2
3@Injectable()
4class ConfigService {
5  public readonly level = 'debug';
6}
7
8@Module({
9  providers: [ConfigService],
10  exports: [ConfigService]
11})
12class ConfigModule {}
13
14@Module({
15  imports: [
16    LoggerModule.forRootAsync({
17      imports: [ConfigModule],
18      inject: [ConfigService],
19      useFactory: async (config: ConfigService) => {
20        await somePromise();
21        return {
22          pinoHttp: { level: config.level },
23        };
24      }
25    })
26  ],
27  ...
28})
29class TestModule {}

Asynchronous logging

In essence, asynchronous logging enables even faster performance by pino.

Please, read pino asynchronous mode docs first. There is a possibility of the most recently buffered log messages being lost in case of a system failure, e.g. a power cut.

If you know what you're doing, you can enable it like so:

1import pino from 'pino';
2import { LoggerModule } from 'nestjs-pino';
3
4@Module({
5  imports: [
6    LoggerModule.forRoot({
7      pinoHttp: {
8        stream: pino.destination({
9          dest: './my-file', // omit for stdout
10          minLength: 4096, // Buffer before writing
11          sync: false, // Asynchronous logging
12        }),
13      },
14    }),
15  ],
16  ...
17})
18class MyModule {}

See pino.destination

Testing a class that uses @InjectPinoLogger

This package exposes a getLoggerToken() function that returns a prepared injection token based on the provided context. Using this token, you can provide a mock implementation of the logger using any of the standard custom provider techniques, including useClass, useValue and useFactory.

1  const module: TestingModule = await Test.createTestingModule({
2    providers: [
3      MyService,
4      {
5        provide: getLoggerToken(MyService.name),
6        useValue: mockLogger,
7      },
8    ],
9  }).compile();

Logger/PinoLogger class extension

Logger and PinoLogger classes can be extended.

1// logger.service.ts
2import { Logger, PinoLogger, Params, PARAMS_PROVIDER_TOKEN } from 'nestjs-pino';
3
4@Injectable()
5class LoggerService extends Logger {
6  constructor(
7    logger: PinoLogger,
8    @Inject(PARAMS_PROVIDER_TOKEN) params: Params
9  ) {
10    ...
11  }
12  // extended method
13  myMethod(): any {}
14}
15
16import { PinoLogger, Params, PARAMS_PROVIDER_TOKEN } from 'nestjs-pino';
17
18@Injectable()
19class LoggerService extends PinoLogger {
20  constructor(
21    @Inject(PARAMS_PROVIDER_TOKEN) params: Params
22  ) {
23    // ...
24  }
25  // extended method
26  myMethod(): any {}
27}
28
29
30// logger.module.ts
31@Module({
32  providers: [LoggerService],
33  exports: [LoggerService],
34  imports: [LoggerModule.forRoot()],
35})
36class LoggerModule {}

Notes on Logger injection in constructor

Since logger substitution has appeared in NestJS@8 the main purpose of Logger class is to be registered via app.useLogger(app.get(Logger)). But that requires some internal breaking change, because with such usage NestJS pass logger's context as the last optional argument in logging function. So in current version Logger's methods accept context as a last argument.

With such change it's not possible to detect if method was called by app internaly and the last argument is context or Logger was injected in some service via constructor(private logger: Logger) {} and the last argument is interpolation value for example.

Assign extra fields for future calls

You can enrich logs before calling log methods. It's possible by using assign method of PinoLogger instance. As Logger class is used only for NestJS built-in Logger substitution via app.useLogger(...) this feature is only limited to PinoLogger class. Example:

1
2@Controller('/')
3class TestController {
4  constructor(
5    private readonly logger: PinoLogger,
6    private readonly service: MyService,
7  ) {}
8
9  @Get()
10  get() {
11    // assign extra fields in one place...
12    this.logger.assign({ userID: '42' });
13    return this.service.test();
14  }
15}
16
17@Injectable()
18class MyService {
19  private readonly logger = new Logger(MyService.name);
20
21  test() {
22    // ...and it will be logged in another one
23    this.logger.log('hello world');
24  }
25}

By default, this does not extend Request completed logs. Set the assignResponse parameter to true to also enrich response logs automatically emitted by pino-http.

Change pino params at runtime

Pino root instance with passed via module registration params creates a separate child logger for every request. This root logger params can be changed at runtime via PinoLogger.root property which is the pointer to logger instance. Example:

1@Controller('/')
2class TestController {
3  @Post('/change-loggin-level')
4  setLevel() {
5    PinoLogger.root.level = 'info';
6    return null;
7  }
8}

Expose stack trace and error class in err property

By default, pino-http exposes err property with a stack trace and error details, however, this err property contains default error details, which do not tell anything about actual error. To expose actual error details you need you to use a NestJS interceptor which captures exceptions and assigns them to the response object err property which is later processed by pino-http:

1import { LoggerErrorInterceptor } from 'nestjs-pino';
2
3const app = await NestFactory.create(AppModule);
4app.useGlobalInterceptors(new LoggerErrorInterceptor());

Migration

v1

• All parameters of v.0 are moved to pinoHttp property (except useExisting).
• useExisting now accept only true because you should already know if you want to use preconfigured fastify adapter's logger (and set true) or not (and just not define this field).

v2

Logger substitution

A new more convenient way to inject a custom logger that implements LoggerService has appeared in recent versions of NestJS (mind the bufferLogs field, it will force NestJS to wait for logger to be ready instead of using built-in logger on start):

1// main.ts
2import { Logger } from 'nestjs-pino';
3// ...
4  const app = await NestFactory.create(AppModule, { bufferLogs: true });
5  app.useLogger(app.get(Logger));
6// ...

Note that for standalone applications, buffering has to be flushed using app.flushLogs() manually after custom logger is ready to be used by NestJS (refer to this issue for more details):

1// main.ts
2import { Logger } from 'nestjs-pino';
3
4// ... 
5  const app = await NestFactory.createApplicationContext(AppModule, { bufferLogs: true });
6  app.useLogger(app.get(Logger));
7  app.flushLogs();
8// ...

In all the other places you can use built-in Logger:

1// my-service.ts
2import { Logger } from '@nestjs/common';
3class MyService {
4  private readonly logger = new Logger(MyService.name);
5}

To quote the official docs:

If we supply a custom logger via app.useLogger(), it will actually be used by Nest internally. That means that our code remains implementation agnostic, while we can easily substitute the default logger for our custom one by calling app.useLogger().

That way if we follow the steps from the previous section and call app.useLogger(app.get(MyLogger)), the following calls to this.logger.log() from MyService would result in calls to method log from MyLogger instance.

---

This is recommended to update all your existing Logger injections from nestjs-pino to @nestjs/common. And inject it only in your main.ts file as shown above. Support of injection of Logger (don't confuse with PinoLogger) from nestjs-pino directly in class constructors is dropped.

---

Since logger substitution has appeared the main purpose of Logger class is to be registered via app.useLogger(app.get(Logger)). But that requires some internal breaking change, because with such usage NestJS pass logger's context as the last optional argument in logging function. So in current version Logger's methods accept context as the last argument.

With such change it's not possible to detect if method was called by app internaly and the last argument is context or Logger was injected in some service via constructor(private logger: Logger) {} and the last argument is interpolation value for example. That's why logging with such injected class still works, but only for 1 argument.

NestJS LoggerService interface breaking change

In NestJS@8 all logging methods of built-in LoggerService now accept the same arguments without second context argument (which is set via injection, see above), for example: log(message: any, ...optionalParams: any[]): any;. That makes usage of built-in logger more convenient and compatible with pino's logging methods. So this is a breaking change in NestJS, and you should be aware of it.

In NestJS <= 7 and nestjs-pino@1 when you call this.logger.log('foo', 'bar'); there would be such log: {..."context":"bar","msg":"foo"} (second argument goes to context field by desing). In NestJS 8 and nestjs-pino@2 (with proper injection that shown above) same call will result in {..."context":"MyService","msg":"foo"}, so context is passed via injection, but second argument disappear from log, because now it treats as interpolation value and there should be placeholder for it in message argument. So if you want to get both foo and bar in log the right way to do this is: this.logger.log('foo %s', 'bar');. More info can be found in pino docs.

FAQ

Q: How to disable automatic request/response logs?

A: check out autoLogging field of pino-http that are set in pinoHttp field of Params

---

Q: How to pass X-Request-ID header or generate UUID for req.id field of log?

A: check out genReqId field of pino-http that are set in pinoHttp field of Params

---

Q: How does it work?

A: It uses pino-http under hood, so every request has it's own child-logger, and with help of AsyncLocalStorage Logger and PinoLogger can get it while calling own methods. So your logs can be grouped by req.id.

---

Q: Why use AsyncLocalStorage instead of REQUEST scope?

A: REQUEST scope can have perfomance issues. TL;DR: it will have to create an instance of the class (that injects Logger) on each request, and that will slow down your response times.

---

Q: I'm using old nodejs version, will it work for me?

A: Please check out history of this feature.

---

Q: What about pino built-in methods/levels?

A: Pino built-in methods names are not fully compatible with NestJS built-in LoggerService methods names, and there is an option which logger you use. Here is methods mapping:

pino method	PinoLogger method	NestJS built-in Logger method
trace	trace	verbose
debug	debug	debug
info	info	log
warn	warn	warn
error	error	error
fatal	fatal	fatal (since nestjs@10.2)

---

Q: Fastify already includes pino, and I want to configure it on Adapter level, and use this config for logger

A: You can do it by providing useExisting: true. But there is one caveat:

Fastify creates logger with your config per every request. And this logger is used by Logger/PinoLogger services inside that context underhood.

But Nest Application has another contexts of execution, for example lifecycle events, where you still may want to use logger. For that Logger/PinoLogger services use separate pino instance with config, that provided via forRoot/forRootAsync methods.

So, when you want to configure pino via FastifyAdapter there is no way to get back this config from fastify and pass it to that out of context logger.

And if you will not pass config via forRoot/forRootAsync out of context logger will be instantiated with default params. So if you want to configure it with the same options for consistency you have to provide the same config to LoggerModule configuration too. But if you already provide it to LoggerModule configuration you can drop useExisting field from config and drop logger configuration on FastifyAdapter, and it will work without code duplication.

So this property (useExisting: true) is not recommended, and can be useful only for cases when:

• this logger is not using for lifecycle events and application level logging in NestJS apps based on fastify
• pino is using with default params in NestJS apps based on fastify

All the other cases are lead to either code duplication or unexpected behavior.

---

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Also if you are into NestJS you might be interested in one of my other NestJS libs.