Readyator

Waits for specified urls or ports on localhost to be ready before running a supplied command.

Installation

npm

1npm install readyator

Yarn

1yarn add readyator

Usage

Preface

• Addresses (ports or urls) must be separated by comma if you want to check for multiple services to be ready ( returning a successful HTTP status code).
• Your command must be surrounded by quotes so that it can be properly parsed.
• The default check interval is 1s (1000ms) but can be changed.

Wait for ports

Command:

1readyator [ports] [command]

Example:

1readyator 8080,8081 "npm run start"

If you're not looking to perform any specific actions but simply want to determine when the service is available, use this command:

1readyator 8080,8081 "exit 0"

Wait for URLs

Command:

1readyator [urls] [command]

Example:

1readyator https://www.google.com/,http://localhost:8081/ "npm run start"

Change check interval

Command:

1readyator [urls] [command] [interval_in_millis]

Example:

1readyator https://www.google.com/ "npm run start" 5000

Wait for healthy Docker container

Command:

1readyator-docker [container_name] [interval_in_millis]

Example:

1readyator-docker my_docker_container 1000

Node.js API

You can use readyator also through its Node.js API:

1import readyator from 'readyator';
2
3await readyator([8080, 8081], 'npm run start');

It also supports executing a callback function:

1import readyator from 'readyator';
2
3const callback = () => {
4  console.log('System is online!');
5};
6
7readyator([8080, 8081], callback);

Readyator's programmatic interface can also be used to listen for Docker containers to become healthy:

1import {runWhenHealthy} from 'readyator';
2
3await runWhenHealthy('my_docker_container');

Development

Here is how you can easily test the readyator from your development environment when checking out the code:

1npm start https://www.google.com/ "npm run exit"