log.md

Log Module

Offers a log service with predefined severity levels. When called, broadcasts the message to all connected transports and based on their own configuration decide whether or not to publish at it.

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Usage

Inject LogService at your provide and call any of its method based on severity:

import { LogService } from '@bechara/crux';

@Injectable()
export class FooService {

  public constructor(
    private readonly fooRepository: Repository<FooEntity>,
    private readonly logService: LogService,
  ) { }

  public async readFooById(id: number) {
    let foo: FooEntity;
    this.logService.debug(`Reading foo with id ${id}`);

    try {
      foo = await this.FooRepository.readById(id);
    }
    catch (e) {
      this.logService.error(`Failed to read foo`, e, id);
      throw new InternalServerErrorException();
    }

    this.logService.notice(`Successfully read foo with id ${id}`);
    return foo;
  }
}

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Call Signatures

The logging method accepts multiples arguments of the following typing:

type LogArguments = string | Error | Record<string, any>;

Which means you may call them in any combination of:

this.logService.error(a: string);
this.logService.error(a: string, b: Error);
this.logService.error(a: string, b: Record<string, any>);
this.logService.error(a: Error, b: Record<string, any>);
this.logService.error(a: string, b: Record<string, any>, c: Record<string, any>);
this.logService.error(a: string, b: Error, c: Record<string, any>);
this.logService.error(a: Error, b: Record<string, any>, c: Record<string, any>);
this.logService.error(a: string, b: Error, c: Record<string, any>, d: Record<string, any>);
// etc...

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Transporters

This package offers the following built-in transporters: Console and Loki.

Configuration will be acquired from environment according to the following variables.

Console

Print messages at stdout, enabled by default.

Variable	Required	Type	Default
CONSOLE_SEVERITY	No	string	trace when NODE_ENV=local, warning otherwise

Loki

Publish logs to Loki by pushing through its API.

To enable this integration provide LOKI_URL, you may also provide basic auth credentials.

Variable	Required	Type	Default
LOKI_URL	Yes	string
LOKI_USERNAME	No	string
LOKI_PASSWORD	No	string
LOKI_SEVERITY	No	string	debug

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