[api][webui] Update Notification to use JSON serialisation.

Otherwise the Event.payload gets parsed from json, then serialised as YAML
into Notification.event_payload which sometimes causes errors because
the payload can fit into the events table (with JSON serialisation) but
might not fit into notifications.event_payload becuase YAML
serialisation takes up more characters than JSON does.

ReleaseNotes-2.9

@@ -23,6 +23,11 @@ OBS Appliance users who have setup their LVM can just replace
 their appliance image without data loss. The migration will
 happen automatically.
 
+Upgrading from previous versions:
+=================================
+
+ * Please run this rake task if you notifications table has any rows in it:
+ rake db:convert_notifications_serialization
 
 Features
 ========

src/api/app/models/notification.rb

@@ -1,7 +1,7 @@
 class Notification < ApplicationRecord
   belongs_to :subscriber, polymorphic: true
 
-  serialize :event_payload, Hash
+  serialize :event_payload, JSON
 
   def event
     @event ||= event_type.constantize.new(event_payload)

src/api/lib/tasks/databases.rake

@@ -1,3 +1,5 @@
+require_relative '../../app/models/application_record'
+
 module Rake
   module TaskManager
     def redefine_task(task_class, *args, &block)
@@ -120,4 +122,55 @@ namespace :db do
     Rake::Task["db:structure:load"].invoke
     Rake::Task["db:seed"].invoke
   end
+
+  desc "Convert existing notifications to use JSON serialization for the event_payload column"
+  task convert_notifications_serialization: :environment do
+    NotificationForRakeTask.transaction do
+      NotificationForRakeTask.all.find_each do |notification|
+        json = yaml_to_json(notification.event_payload)
+        notification.update_attributes!(event_payload: json)
+      end
+    end
+  end
+end
+
+def yaml_to_json(yaml)
+  YAML.safe_load(yaml)
+      .traverse do |value|
+        if value.is_a? String
+          value.force_encoding('UTF-8')
+        else
+          value
+        end
+      end
+      .to_json
+end
+
+# Notification model only for migration in order to avoid errors coming from the serialization in the actual Notification model
+class NotificationForRakeTask < ::ApplicationRecord
+  self.table_name = 'notifications'
+  self.inheritance_column = :_type_disabled
+end
+
+# Hash extension is used to run force_encoding against each string value in the hash
+# in rake tasks to convert yaml to json serialisation for event payloads
+class Hash
+  def traverse(&block)
+    traverse_value(self, &block)
+  end
+
+  private
+
+  def traverse_value(value, &block)
+    if value.is_a? Hash
+      value.each { |key, sub_value| value[key] = traverse_value(sub_value, &block) }
+
+    elsif value.is_a? Array
+      value.map { |element| traverse_value(element, &block) }
+
+    else
+      yield(value)
+
+    end
+  end
 end

src/api/spec/jobs/send_event_emails_job_spec.rb

@@ -43,6 +43,14 @@
         expect(notification.delivered).to be_falsey
       end
 
+      it "creates an rss notification with the same raw value of the corresponding event's payload" do
+        notification = Notification.find_by(subscriber: user)
+        raw_event_payload = Event::Base.first.attributes_before_type_cast['payload']
+        raw_notification_payload = notification.attributes_before_type_cast['event_payload']
+
+        expect(raw_event_payload).to eq(raw_notification_payload)
+      end
+
       it "creates an rss notification for group's email" do
         notification = Notification::RssFeedItem.find_by(subscriber: group)
 

src/api/spec/lib/tasks/databases_spec.rb

@@ -0,0 +1,21 @@
+require 'rails_helper'
+
+RSpec.describe 'rake db' do
+  describe '#convert_notifications_serialization' do
+    let!(:yaml) { "---\nhello: world\nhow:\n- are\n- you\n- today?\nim: fine thanks\n" }
+    let!(:notification) { create(:notification, type: 'Notification::RssFeedItem') }
+    let!(:task) { Rake::Task['db:convert_notifications_serialization'] }
+
+    before do
+      sql = "UPDATE `notifications` SET `event_payload` = '#{yaml}' WHERE id = #{notification.id}"
+      ActiveRecord::Base.connection.execute(sql)
+    end
+
+    subject! { task.execute }
+
+    it 'converts the notifications event_payload from yaml to json' do
+      json_hash = { "hello" => "world", "how" => ["are", "you", "today?"], "im" => "fine thanks"}
+      expect(Notification.first.event_payload).to eq(json_hash)
+    end
+  end
+end

src/api/spec/spec_helper.rb

@@ -80,6 +80,10 @@
       config.formatter = 'NyanUnicornFormatter'
     end
   end
+
+  config.before(:suite) do
+    Rails.application.load_tasks
+  end
 end
 
 # We never want the backend to autostart itself...