Correlation Logger

Correlation logger is custom logger written to manage all types of logs in your microservices. It can log each request and reponse of the microservice. Additionally it can also be used to log error and info with correlationId.

Setup

Install

npm install --save correlation-logger

Add variable in '.env' file in root of your service

STORE_APP_NAME=your-app-name
ENV=production

value STORE_APP_NAME should not contain spaces. Other supported ENVs are test, staging, development.

Create logs folder and put it in .gitignore

mkdir logs
echo logs/ >> .gitignore

It writes logs in logs/combined.log.

How to use

To log Request and Response

Add the below lines to the microservice's server file ("app" in the code is an implied reference to an instance of Express()):

const requestLogger = require("correlation-logger");  

requestLogger(app);  

To add custom logging

const { logger } = require("correlation-logger/logger");  

// To log information
logger.info("some useful", "information");

// to log error
logger.error("some-error", "more info");

Other supported methods are -

• warn
• verbose
• debug
• silly

To forward correlation-id in request and request-promise

This is needed if you wanna track a request flowing through several microservices.

// It returns a wrapper around `request` package with added default `correlation-id` header
const request = require("correlation-logger/request")

If you are using request-promise-native package. Use below wrapper for default correlation-id header

// It returns a wrapper around `request-promise-native` package with added default correlation-id header
const requestPromiseNative = require("correlation-logger/request-promise-native")

Likewise to use wrapper of request-promise package. Use below wrapper

// It returns a wrapper around `request-promise` package with added default correlation-id header
const requestPromise = require("correlation-logger/request-promise")