What is Canary?

Canary checks the status of a provided source and performs a callback function when that status changes. It is inspired by the CLI util netcat and powered by cron and netcat.

Use Canary to notify your developers of critical connection failures.

Basic Usage

const { healthCheck } = require('canary-bird');

// start
const myHealthcheck = healthCheck({
    ip: <target ip>,
    port: <target port>,
    onComplete: (report) => console.log('checked server status', report),
    repeat: '* * * * * *', // every second
}).start();

// stop
myHealthCheck.stop();

Your onChange function will always be called with a report object matching this format:

{
    ip: 'xxx.xx.xx.xxx',
    port: 8080,
    listening: true,
}

Required Configuration

repeat: How often to repeat the health check. Supports a value that is in standard cron format.

onComplete: The function to perform when the health check completes.

ip: The ip address of the server you'd like to check.

port: The port that the target service should be listening on.

Optional Configuration

timezone: The desired timezone to schedule the health check with. Defaults to America/New_York.

timeout: How long you want to your netcat command to wait for a connection. Defaults to 1 second.