resources/etcd_key.rb

require 'etcd'

resource_name :etcd_key
provides :etcd_key

property :key, String, name_property: true, desired_state: false
property :value, String
property :ttl, String, desired_state: false
property :host, String, default: '127.0.0.1', desired_state: false
property :port, Integer, default: 2379, desired_state: false

def etcd
  @etcd ||= ::Etcd.client(host: host, port: port)
end

def with_retries(&_block)
  tries = 5
  begin
    yield
    # Only catch errors that can be fixed with retries.
  rescue Errno::ECONNREFUSED
    sleep 5
    tries -= 1
    retry if tries > 0
    raise
  end
end

def key_exist?
  true if etcd.get(key)
rescue Etcd::KeyNotFound,
       Errno::ECONNREFUSED
  false
end

load_current_value do
  value etcd.get(key).value if key_exist?
end

action :set do
  converge_if_changed do
    opts = { value: new_resource.value }
    opts[:ttl] = new_resource.ttl if new_resource.ttl
    converge_by "will set value of key #{new_resource.key}" do
      with_retries { etcd.set(new_resource.key, opts) }
    end
  end
end

action :delete do
  if key_exist?
    converge_by "delete key #{new_resource.key}" do
      with_retries { etcd.delete(new_resource.key) }
    end
  end
end

action :watch do
  converge_by "watching for updates of #{new_resource.key}" do
    with_retries { etcd.watch(new_resource.key) }
  end
end