Add Slack notifier (#5)

* Add slack notifier and service class to ping

* add global class method.

* update service class

* Finalize Slack notifier service

* Remove duplicate gem

Gemfile

@@ -18,6 +18,7 @@ gem 'pg', '~> 0.18'
 gem 'puma', '~> 3.7'
 gem 'rails', '~> 5.1.1'
 gem 'sass-rails', '~> 5.0'
+gem 'slack-notifier', '~> 2.2.2'
 gem 'turbolinks', '~> 5'
 gem 'uglifier', '>= 1.3.0'
 gem 'webpacker', '~> 2.0'

Gemfile.lock

@@ -202,6 +202,7 @@ GEM
     selenium-webdriver (3.5.0)
       childprocess (~> 0.5)
       rubyzip (~> 1.0)
+    slack-notifier (2.2.2)
     spring (2.0.2)
       activesupport (>= 4.2)
     spring-watcher-listen (2.0.1)
@@ -270,6 +271,7 @@ DEPENDENCIES
   rails (~> 5.1.1)
   sass-rails (~> 5.0)
   selenium-webdriver
+  slack-notifier (~> 2.2.2)
   spring
   spring-watcher-listen (~> 2.0.0)
   turbolinks (~> 5)

app/models/setting.rb

@@ -10,6 +10,10 @@ class Setting < ApplicationRecord
 
   before_create :validate_only_one_setting_record
 
+  def self.global
+    first
+  end
+
   private
 
   def validate_only_one_setting_record

app/services/notifiers/slack_notifier.rb

@@ -0,0 +1,36 @@
+module Notifiers
+  # SlackNotifier
+  #
+  # Send messages directly to your Slack channel.
+  class SlackNotifier
+    attr_reader(:message, :bot)
+
+    def initialize(message, bot = nil)
+      @message = message
+      @bot = bot
+    end
+
+    def notify!
+      raise('Slack URL is not set') unless slack_url.present?
+      notifier.ping(message, icon_url: icon_url)
+    end
+
+    private
+
+    def slack_url
+      @slack_url ||= Setting.global.slack_url
+    end
+
+    def notifier
+      Slack::Notifier.new(slack_url, username: bot_username)
+    end
+
+    def bot_username
+      bot.present? ? bot : 'storm'
+    end
+
+    def icon_url
+      'https://s3-us-west-2.amazonaws.com/storm-app/icon.png'
+    end
+  end
+end

test/factories/settings.rb

@@ -1,4 +1,5 @@
 FactoryGirl.define do
   factory :setting do
+    slack_url('127.0.0.1/slack')
   end
 end

test/models/setting_test.rb

@@ -12,4 +12,10 @@ class SettingTest < ActiveSupport::TestCase
     assert(setting.save)
     assert_not_nil(setting.encrypted_aws_secret)
   end
+
+  test 'global' do
+    assert_nil(Setting.global)
+    setting = create(:setting)
+    assert_equal(setting, Setting.global)
+  end
 end

test/services/notifiers/slack_notifier_test.rb

@@ -0,0 +1,22 @@
+require('test_helper')
+
+module Notifiers
+  # SlackNotifierTest
+  class SlackNotifierTest < ActiveSupport::TestCase
+    test 'bot_username' do
+      instance = Notifiers::SlackNotifier.new('msg')
+      assert_equal('storm', instance.send(:bot_username))
+
+      instance = Notifiers::SlackNotifier.new('msg', 'bot')
+      assert_equal('bot', instance.send(:bot_username))
+    end
+
+    test 'notify! without a Slack URL present' do
+      create(:setting, slack_url: nil)
+
+      assert_raise do
+        Notifiers::SlackNotifier.new('msg').notify!
+      end
+    end
+  end
+end