#315 Rollout and Degrade pro

gem 'redis'
gem 'rollout'
gem 'degrade'

$redis = Redis.new
$rollout = Rollout.new($redis)
$rollout.define_group(:admin) do |user|
  user.admin?
end
$degrade_phone = Degrade.new($redis,
  name: :phone,
  minimum: 1,
  failure_strategy: lambda { $rollout.deactivate_all(:phone) }
)

<% if rollout? :phone %>
  <p><%= link_to "Send to Phone", new_phone_request_path %></p>
<% end %>

def rollout?(name)
  $rollout.active? name, current_user
end
helper_method :rollout?

before_filter :rollout
around_filter :degrade

private

def rollout
  unless rollout? :phone
    redirect_to root_url, alert: "Access denied"
  end
end

def degrade
  $degrade_phone.perform { yield }
end

$rollout.activate_group(:phone, :admin)
$rollout.activate_group(:phone, :all)
$rollout.activate_user(:phone, User.find_by_name("ryan"))
$rollout.activate_percentage(:phone, 20)
$rollout.deactivate_all(:phone)

# Generated with:
# rails g model rollout name:string group:string user_id:integer percentage:integer failure_count:integer
class Rollout < ActiveRecord::Base
  def match?(user)
    enabled? && match_group?(user) && match_user?(user) && match_percentage?(user)
  end

  def enabled?
    failure_count.to_i < 1
  end

  def match_group?(user)
    case group
    when "admin" then user.admin?
    else true
    end
  end

  def match_user?(user)
    user_id ? user_id == user.id : true
  end

  def match_percentage?(user)
    percentage ? user.id % 100 < percentage : true
  end
end

def rollout?(name)
  Rollout.where(name: name).any? do |rollout|
    rollout.match?(current_user)
  end
end
helper_method :rollout?

def degrade_feature(name)
  yield
rescue StandardError => e
  Rollout.where(name: name).each do |rollout|
    rollout.increment!(:failure_count)
  end
  raise e
end

before_filter :rollout
around_filter :degrade

private

def rollout
  redirect_to root_url, alert: "Feature unavailable" unless rollout? :phone
end

def degrade
  degrade_feature(:phone) { yield }
end

Rollout.create! name: "phone", group: "admin"