A simple Javascript round robin health checker

Install

npm install @aftonbladet/health-check --save

Usage

Simple initialization

import { initHealthCheck, isHealthy } from '@aftonbladet/health-check';

initHealthCheck({ healthCheckUrls: ['http://www.aftonbladet.se/'] });

if (isHealthy()) {
    // System is UP
} else {
    // System is DOWN!
}

This will initialize a health checker that checks http://www.aftonbladet.se every three seconds. If any of five consecutive checks returns a status in the 200 to 299 range, the check is considered to be healthy.

Advanced initialization

import { initHealthCheck, isHealthy } from '@aftonbladet/health-check';

initHealthCheck({
    healthCheckUrls: ['http://www.aftonbladet.se/', 'https://www.aftonbladet.se/sportbladet'],
    healthCheckInterval, 1000,
    numberOfChecks: 3,
});

if (isHealthy()) {
    // System is UP
} else {
    // System is DOWN!
}

This will instead initialize a health checker that round robins through the URLs in healthCheckUrls every second. If any of three consecutive checks returns a status in the 200 to 299 range, the check is considered to be healthy.

The following parameters are accepted by initHealthCheck:

• healthCheckUrls a list of URLs to check
• [healthCheckInterval=3000] the time in ms to wait in between each URL to check
• [readTimeout=1000] the read timeout in ms used when checking the URLs
• [numberOfChecks=5] the size of the CHECKS array
• [logger=NOOP] a https://github.schibsted.io/ab/logger instance if you want logging

Publish

npm version major|minor|patch