Provides a Ruby wrapper around the CoreOS Fleet API.

The client allows programmatic access to most of the fleetctl commands including the ability to load, start, stop, unload and destroy unit files.

At this point, there is no official Fleet API (though one is in the works) so this library mimcs the behavior of the fleetctl command line tool and simply writes data to the etcd key-value-store. The Fleet daemon reads data out of specific keys in etcd and processes it as appropiate.

As work on the actual Fleet API progresses, this library will be refactored to use the real API. An initial pass at implementing a client for the official Fleet API can be found on the feature/official-api branch.

An alternative implementation is available in the cloudspace/ruby-fleetctl gem. The ruby-fleetctl gem takes a different approach and uses SSH to interact directly with the fleetctl binary to send commands. Our approach of writing directly to etcd cuts out the fleetctl middleman but is in more danger of being broken by future releases since we're effectively using a "private API".

The current version of the fleet-api gem is known to work with version 0.6.0 of Fleet.

Install the gem directly:

gem install fleet-api

Alternatively, add this line to your application's Gemfile:

gem 'fleet-api', require: 'fleet'

Configure the URL for the etcd API:

require 'fleet'

Fleet.configure do |fleet|
  fleet.fleet_api_url = 'http://10.1.42.1:4001'
end

If you don't provide an explicit value for the .fleet_api_url attribute, it will default to using the value of the FLEETCTL_ENDPOINT environment variable.

Note: since this Fleet API is not yet available in the stable version of CoreOS, the URL value provided must be the endpoint for the etcd API.

When submitting a service definition to the Fleet::Client you must convert your unit file into a Ruby hash. Each section in the unit file is represented as a key/value pair in the hash where the key is the name of the section and the value is another hash containing all the statements for that section.

For example, look at the following unit file.

[Unit]
Description=Useless infinite loop

[Service]
ExecStart=/bin/bash -c "while true; do sleep 1; done"

This unit file would be represented as the following Ruby hash.

{
  'Unit' => {
    'Description' => 'Useless infinite loop'
  },
  'Service' => {
    'ExecStart' => "/bin/bash -c \"while true; do sleep 1; done\""
  }
}

Equivalent of fleetctl load:

service = {
  'Unit' => {
    'Description' => 'Useless infinite loop'
  },
  'Service' => {
    'ExecStart' => "/bin/bash -c \"while true; do sleep 1; done\""
  }
}

client = Fleet.new
client.load('forever.service', service)

Note that the name you pass-in as the first parameter to the .load method should end in ".service"

Equivalent of fleetctl start:

client = Fleet.new
client.start('forever.service')

Equivalent of fleetctl stop:

client = Fleet.new
client.stop('forever.service')

Equivalent of fleetctl unload:

client = Fleet.new
client.unload('forever.service')

Equivalent of fleetctl destroy:

client = Fleet.new
client.destroy('forever.service')

Equivalent of fleetctl status:

client = Fleet.new
client.status('forever.service')