cache notifications in memory

test plan:
* use canvas and ensure that notifications work

Change-Id: Ie46f049aab5dde7167c3ea4228e503c7a686c839
Reviewed-on: https://gerrit.instructure.com/9154
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>

app/models/alert.rb

@@ -255,7 +255,7 @@ class Alert < ActiveRecord::Base
   end
 
   def self.send_alert(alert, user_ids, student_enrollment)
-    notification = Notification.find_by_name("Alert")
+    notification = Notification.by_name("Alert")
     notification.create_message(alert, user_ids, {:asset_context => student_enrollment})
   end
 end

app/models/delayed_message.rb

@@ -112,7 +112,7 @@ class DelayedMessage < ActiveRecord::Base
     user = to.user rescue nil
     context = delayed_messages.select{|m| m.context}.compact.first.try(:context)
     return nil unless context # the context for this message has already been deleted
-    notification = Notification.find_by_name('Summaries')
+    notification = Notification.by_name('Summaries')
     path = HostUrl.outgoing_email_address
     message = notification.messages.build(
       :subject => notification.subject,

app/models/notification.rb

@@ -74,7 +74,21 @@ class Notification < ActiveRecord::Base
   end
   
   def self.summary_notification
-    find_by_name('Summaries')
+    by_name('Summaries')
+  end
+
+  def self.by_name(name)
+    @notifications ||= Notification.all.inject({}){ |h, n| h[n.name] = n; h }
+    if notification = @notifications[name]
+      copy = notification.clone
+      copy.id = notification.id
+      copy.send(:remove_instance_variable, :@new_record)
+      copy
+    end
+  end
+
+  def self.reset_cache!
+    @notifications = nil
   end
 
   def infer_default_content

lib/canvas/account_reports.rb

@@ -60,8 +60,8 @@ module Canvas::AccountReports
   def self.message_recipient(account_report, message, csv=nil)
     user = account_report.user
     account = account_report.account
-    notification = Notification.find_by_name("Report Generated")
+    notification = Notification.by_name("Report Generated")
-    notification = Notification.find_by_name("Report Generation Failed") if !csv
+    notification = Notification.by_name("Report Generation Failed") if !csv
     attachment = nil
     if csv
       require 'action_controller'

spec/models/notification_spec.rb

@@ -44,6 +44,26 @@ describe Notification do
     n.subject.should_not be_nil
     n.sms_body.should_not be_nil
   end
+
+  context "by_name" do
+    before do
+      Notification.create(:name => "foo")
+      Notification.create(:name => "bar")
+    end
+
+    it "should look up all notifications once and cache them thereafter" do
+      Notification.expects(:all).once.returns{ Notification.find(:all) }
+      Notification.by_name("foo").should eql(Notification.find_by_name("foo"))
+      Notification.by_name("bar").should eql(Notification.find_by_name("bar"))
+    end
+
+    it "should give you different object for the same notification" do
+      n1 = Notification.by_name("foo")
+      n2 = Notification.by_name("foo")
+      n1.should eql n2
+      n1.should_not equal n2
+    end
+  end
   
   context "create_message" do
     it "should only send dashboard messages for users with non-validated channels" do

spec/spec_helper.rb

@@ -97,6 +97,7 @@ Spec::Runner.configure do |config|
   config.before :all do
     # so before(:all)'s don't get confused
     Account.clear_special_account_cache!
+    Notification.after_create { Notification.reset_cache! }
   end
 
   config.before :each do
@@ -105,6 +106,7 @@ Spec::Runner.configure do |config|
     Account.default.update_attribute(:default_time_zone, 'UTC')
     Setting.reset_cache!
     HostUrl.reset_cache!
+    Notification.reset_cache!
     ActiveRecord::Base.reset_any_instantiation!
   end
 

vendor/plugins/broadcast_policy/lib/broadcast_policy.rb

@@ -126,8 +126,7 @@ module Instructure #:nodoc:
           record.messages_failed[self.dispatch] = "Did not meet condition."
           return false
         end
-        notification = record.notifications.find_by_name(self.dispatch) rescue nil
+        notification = Notification.by_name(self.dispatch)
-        notification ||= Notification.find_by_name(self.dispatch)
         # logger.warn "Could not find notification for #{record.inspect}" unless notification
         unless notification
           record.messages_failed[self.dispatch] = "Could not find notification: #{self.dispatch}."