1.0.4 • Published 10 years ago

chillin v1.0.4

Weekly downloads
3
License
MIT
Repository
github
Last release
10 years ago

Introduction

This tool is intended to be used either in bash or a node.js project. It waits for a resource (such as a database) to become available, then it starts another process. It just chills until the timeout expires or the wait condition is satisfied.

Let's illustrate with an example. Say you have a Docker Compose environment that starts containers S and D (for database). S depends on D, but D can be slow to start up. S can use chillin in either of two ways.

  1. The NodeJS startup script can be modified to use the chillin NPM package.
  2. A startup bash script can utilize the chillin CLI.

Please Note Chillin uses EcmaScript 6. It will not run on older versions of NodeJS!

NodeJS Example

const chillin = require('chillin')
    , promise = chillin.loadWaiterModule('port')
        .configure('host', 'www.google.com')
        .configure('port', 80)
        .start()

promise.then(function(){
    console.log('OK!')
}, function(x){
    console.error(`Failed: ${x}`)
})

To Run Chillin Inside Your Project

> npm install chillin --save-dev
> export PATH=$PATH:$(npm bin)
> chillin port www.google.com 80

BASH Example

Please reference the example above if you are installing Chillin in your project rather than as a global package. The line that changes the PATH variable can be added to the example below to make it run with a locally installed package.

#!/usr/bin/env bash

if [ $# -lt 1 ]; then
    echo "Name/IP of Postgres server required." 1>&2;
    echo "> $0 PGSERVER" 1>&2;
    exit 1
fi

#If you want to suppress error output on failure, you can redirect
#stderr to null on the next line.
chillin port $1 5432
#Get the exit code
RESULT=$?

if [ $RESULT == 0 ]; then
    echo "Starting the program that depends on Postgres..."
else
    echo "Failed! Not starting the program." 1>&2
    exit $RESULT
fi

Types of Waits

There are three built-in waiter modules: port, exec, and mock. The port waiter is shown in the examples. The exec module waits for a process to start and complete or time out. The mock module is for testing purposes. Other modules may be loaded using a path consistent with require() in NodeJS.

The port Waiter

chillin www.github.com 80 --timeout 2000

The positional arguments are ADDRESS PORT

The exec Waiter

chillin --timeout 2000 echo "Hello"

The positional arguments correspond to COMMAND arg1 arg2 ... argN

1.0.4

10 years ago

1.0.3

10 years ago

1.0.2

10 years ago

1.0.1

10 years ago

1.0.0

10 years ago