cloud

cloud

Remote execution with VPC support, kinda like fabric/capistrano for node with greater scripting control via generators.

Installation

$ npm install cloud

Usage

  Usage: cloud <task ...>

  Options:

    -h, --help             output usage information
    -D, --dry-run          perform a dry run
    -t, --tasks            output list of available tasks
    -H, --hosts            output list of available hosts
    -v, --verbose          output verbose log information
    -c, --concurrency <n>  task execution concurrency [1]

Guide

When cloud.parse(argv) is run it turns your script into a CLI, so flags such as --help and --tasks are available, and arguments may be passed to execute tasks.

Here's a contrived example that runs hostname on private hosts in a VPC:

var Cloud = require('cloud');

var c = new Cloud;

var stage = c.host('stage', {
  key: '~/.ec2/my.pem',
  user: 'ec2-user',
  address: 'n.n.n.n'
});

c.task('stage', 'stage everything', ['stage:site', 'stage:api', 'stage:ingestion']);

c.task('stage:site', 'stage site', function *(){
  console.log(yield stage.exec('hostname'));
});

c.task('stage:api', 'stage api', function *(){
  console.log(yield stage.exec('hostname', 'api'));
});

c.task('stage:ingestion', 'stage ingestion', function *(){
  console.log(yield stage.exec('hostname', 'ingestion'));
});

c.parse(process.argv);

Listing tasks

To list tasks use the -t, --tasks flag:

node --harmony cloud -t

             stage — stage everything
        stage:site — stage site
         stage:api — stage api
   stage:ingestion — stage ingestion

Executing commands

Executing remote commands is simple, just execute host.exec(command), optionally passing a private hostname to execute on a private host:

var uptime = yield stage.exec('uptime');
var uptime = yield stage.exec('uptime', 'api-1');
var uptime = yield stage.exec('uptime', 'api-2');
var uptime = yield stage.exec('uptime', 'api-3');

If you're running many commands on a private host, you may want to create a new Host object to reference it, for example the following are equivalent:

var a = yield stage.exec('foo', 'api-1');
var b = yield stage.exec('bar', 'api-1');
var c = yield stage.exec('baz', 'api-1');

var api = stage.host('api-1');
var a = yield api.exec('foo');
var b = yield api.exec('bar');
var c = yield api.exec('baz');

Since cloud uses Co you may also execute in parallel:

var res = yield [
  stage.exec('uptime', 'api-1'),
  stage.exec('uptime', 'api-2')
];

var uptime1 = res[0];
var uptime2 = res[1];

Or assign to an object:

var uptimes = {
  api1: stage.exec('uptime', 'api-1'),
  api2: stage.exec('uptime', 'api-2')
};

Executing shell scripts

To execute shell scripts from local disk use the host.run(script) method:

yield stage.run('provision.sh');

You may also specify a private host just like host.exec():

yield stage.run('provision.sh', 'api-1');
yield stage.run('provision.sh', 'api-2');
yield stage.run('provision.sh', 'api-3');

Executing dependencies

One method of defining dependencies is by passing an array as shown in the following example:

c.task('stage', 'stage everything', ['stage:site', 'stage:api', 'stage:ingestion']);

You may also utilize c.task(name) to execute programmatically:

c.task('stage', 'stage everything', function *(){
  yield c.task('stage:api');
  yield c.task('stage:site');
  yield c.task('stage:ingestion');
});

This gives you greater control over flow and concurrency, for example the last two will run in parallel:

c.task('stage', 'stage everything', function *(){
  yield c.task('stage:site');

  yield [
    c.task('stage:api'),
    c.task('stage:ingestion'),
  ];
});

Setting context variables

The this variable becomes a Context which holds all of the values defined via the -s, --set flag. For example -s version=1.2.0 will provide this.version == "1.2.0", and -s debug will set this.debug == true.

You may also omit the -s flag entirely when a value is supplied, for example the follow would be equivalent.

$ mycommand site:run -s cmd=uptime
$ mycommand site:run cmd=uptime

License

MIT