Logger library

This library is responsible for all logging. It supports HTTP (expres) and grpc action logging and nodejs cluster logging (using process messaging). In the background it uses Winston logger.

Logger level priorities

We are using npm levels from the winston itself (the lower the number higher the priority is):

    error: 0,
    warn: 1,
    info: 2,
    http: 3,
    verbose: 4,
    debug: 5,
    silly: 6

Environment variables

This library requires next ENV variables:

Variable name	Description
CONFIG_LOG_LEVEL	Logger levels with lower priority will be skipped
CONFIG_LOG_FORMAT=simple	Logger format logstash or simple (value logstash will format logs in kibana friendly way)

Dependencies

Package	Version
on-headers	^1.0.2
winston	^3.3.3
@betsys-nestjs/config-utils	^2.0.0
@hapi/joi	^17.1.1
@nestjs/common	^10.0.0
@nestjs/config	^3.0.0
@nestjs/core	^10.0.0
express	^4.17.1
reflect-metadata	^0.1.12
rxjs	^7.1.0

Usage

To start using this library simply import LoggerModule to your main application module.

1import {DATA_RETRIEVER, LoggerModule, DataRetrieverService, ContextTypeEnum} from '@betsys-nestjs/logger';
2import {ExpressDefaultDataRetrieverService} from "./express-default-data-retriever.service";
3
4@Module({
5    imports: [
6        LoggerModule.forRoot('express', {
7            provide: DATA_RETRIEVER,
8            useClass: ExpressDefaultDataRetrieverService,
9        }),
10    ]
11})
12class AppModule {
13}

You can define whether you want to use express or grpc in forRoot method. For all platforms there are default data retrievers that are responsible for getting data to log from Request and Response objects based on platform. This can be specified as second parameter of forRoot method and you can add any providers you need to inject to module.

DATA_RETRIVER is defined in provider array and creates a provider with this token. This should be a service that inherits from exposed interface DataRetriever.

For express you can use:

{
    provide: DATA_RETRIEVER, 
    useClass: ExpressDefaultDataRetrieverService,
}

For grpc you can use:

{
    provide: DATA_RETRIEVER, 
    useClass: GrpcDefaultDataRetrieverService,
}

Then inject Logger provider wherever you want to log something.

1import {LoggerModule} from '@betsys/logger';
2
3class AppService {
4    constructor(private readonly logger: Logger) {
5    }
6}

If you for some reason do not trust dependency resolver without providing annotation, you can use @InjectLogger() to provide explicit logger token.

1import {InjectLogger, Logger} from '@betsys/logger';
2
3class AppService {
4    constructor(@InjectLogger() private readonly logger: Logger) {
5    }
6}

Exclude actions from HTTP logging

If you want to exclude any actions from HTTP logging you can mark them using @LoggerExclude().

1import {LoggerExclude} from '@betsys/logger';
2
3@Controller()
4export class CatsController {
5
6    @LoggerExclude()
7    @Get()
8    public getHello(): string {
9    }
10}

Or you can mark whole controllers.

1import {LoggerExclude} from '@betsys/logger';
2
3@LoggerExclude()
4@Controller()
5export class CatsController {
6}