logging-types-lib

Mojaloop Logging Service's Types Lib (and minimal console logger)

This library provides stable logging related types to be used in code that does not require actual implementations of a logger, i.e., code that can use the ILogger interface and expect a concrete implementation to be injected by calling components.

It also provides a minimal ILogger implementation for tests/development purposes only.

Types:

• LogLevel - This enumeration lists the official log levels for the platform;
• ILogger - This is the interface that all Logger implementations must implement, it specifies the mandatory level of functionaly between all implementations;
• LogEntry - This type defines a server side log entry object. Only for advanced usage.
• ConsoleLogger - This is the simplest possible ILogger implementation, that logs to the nodejs/js console.

How to use in components without depending on concrete logger implementations

In the code that doesn't need to be aware of concrete implementations, usually valuable domain code:

import {ILogger} from "@mojaloop/logging-bc-public-types-lib";

// Notice how this code has no knowledge of any concret logger implementations

class MyDomainThing {
    private _logger: ILogger;

    constructor(logger: ILogger) {
        this._logger = logger;
    }

    doAction():void{
        //... do stuff

        this._logger.log("Did stuff");
    }
}

In the application code that usually calls the domain code:

import { ILogger, LogLevel } from "@mojaloop/logging-bc-public-types-lib";
import { DefaultLogger } from "@mojaloop/logging-bc-client-lib";
import { MyDomainThing } from "../domain/my_domain_class";

const BC_NAME = "your_bounded_context_name";
const APP_NAME = "your_app_name";
const APP_VERSION = "0.0.1";
const LOGLEVEL = LogLevel.TRACE;

const loggerImplementation: ILogger = new DefaultLogger(BC_NAME, APP_NAME, APP_VERSION, LOGLEVEL);

// Now we do the dependency injection part by injecting
// the actual implementation via the constructor

const myThing = new MyDomainThing(loggerImplementation);

myThing.doAction();

How to use the console logger

In the application code that usually calls the domain code:

import { ConsoleLogger, ILogger, LogLevel } from "@mojaloop/logging-bc-public-types-lib";

const logger: ILogger = new ConsoleLogger();

logger.debug("debug message");

See also

For more interesting logger implementations, like the DefaultLogger that logs to the console and to a file, or the KafkaLogger that also sends the logs to the central services, see the @mojaloop/logging-bc-client-lib library here

Install

To install this library use:

yarn add @mojaloop/logging-bc-client-lib

OR

npm install @mojaloop/logging-bc-client-lib