Add custom email templates for service desk

- use .gitlab/service_desk_templates as the base dir
- thank_you.md,. new_note.md names required

doc/user/project/service_desk.md

@@ -81,6 +81,33 @@ navigation's **Issues** menu.
 
 ![Service Desk Navigation Item](img/service_desk_nav_item.png)
 
+### Using customized email templates
+
+ > [Introduced](https://gitlab.com/gitlab-org/gitlab/issues/2460) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.7.
+
+When a user submits a new issue using Service Desk, or when a new note is created on a Service Desk issue, an email is sent to the author.
+
+The body of these email messages can customized by using templates. To create a new customized template,
+create a new Markdown (`.md`) file inside the `.gitlab/service_desk_templates/`
+directory in your repository. Commit and push to your default branch.
+
+#### Thank you email
+
+The **Thank you email** is the email sent to a user after they submit an issue.
+The file name of the template has to be `thank_you.md`.
+You can use `%{ISSUE_ID}` placeholder which will be replaced by an issue iid in the email and
+`%{ISSUE_PATH}` placeholder which will be replaced by project path and the issue iid.
+As the service desk issues are created as confidential (only project members can see them)
+the response email doesn't provide the issue link.
+
+#### New note email
+
+The **New note email** is the email sent to a user when the issue they submitted has a new comment.
+The file name of the template has to be `new_note.md`.
+You can use `%{ISSUE_ID}` placeholder which will be replaced by an issue iid
+in the email, `%{ISSUE_PATH}` placeholder which will be replaced by
+ project path and the issue iid and `%{NOTE_TEXT}` placeholder which will be replaced by the note text.
+
 ## Using Service Desk
 
 ### As an end user (issue creator)

ee/app/mailers/emails/service_desk.rb

@@ -3,6 +3,7 @@
 module Emails
   module ServiceDesk
     extend ActiveSupport::Concern
+    include MarkupHelper
 
     included do
       layout 'service_desk', only: [:service_desk_thank_you_email, :service_desk_new_note_email]
@@ -11,11 +12,13 @@ module Emails
     def service_desk_thank_you_email(issue_id)
       setup_service_desk_mail(issue_id)
 
-      options = {
-        from: sender(@support_bot.id, send_from_user_email: false, sender_name: @project.service_desk_setting&.outgoing_name),
-        to: @issue.service_desk_reply_to,
-        subject: "Re: #{@issue.title} (##{@issue.iid})"
-      }
+      email_sender = sender(
+        @support_bot.id,
+        send_from_user_email: false,
+        sender_name: @project.service_desk_setting&.outgoing_name
+      )
+      options = service_desk_options(email_sender, 'thank_you')
+                  .merge(subject: "Re: #{subject_base}")
 
       mail_new_thread(@issue, options)
     end
@@ -24,11 +27,9 @@ module Emails
       @note = Note.find(note_id)
       setup_service_desk_mail(issue_id)
 
-      options = {
-        from: sender(@note.author_id),
-        to: @issue.service_desk_reply_to,
-        subject: "#{@issue.title} (##{@issue.iid})"
-      }
+      email_sender = sender(@note.author_id)
+      options = service_desk_options(email_sender, 'new_note')
+                  .merge(subject: subject_base)
 
       mail_answer_thread(@issue, options)
     end
@@ -42,5 +43,50 @@ module Emails
 
       @sent_notification = SentNotification.record(@issue, @support_bot.id, reply_key)
     end
+
+    def service_desk_options(email_sender, email_type)
+      {
+        from: email_sender,
+        to: @issue.service_desk_reply_to
+      }.tap do |options|
+        next unless template_body = template_content(email_type)
+
+        options[:body] = template_body
+        options[:content_type] = 'text/html'
+      end
+    end
+
+    def template_content(email_type)
+      template = Gitlab::Template::ServiceDeskTemplate.find(email_type, @project)
+
+      text = substitute_template_replacements(template.content)
+
+      markdown(text, project: @project)
+    rescue Gitlab::Template::Finders::RepoTemplateFinder::FileNotFoundError
+      nil
+    end
+
+    def substitute_template_replacements(template_body)
+      template_body
+        .gsub(/%\{\s*ISSUE_ID\s*\}/, issue_id)
+        .gsub(/%\{\s*ISSUE_PATH\s*\}/, issue_path)
+        .gsub(/%\{\s*NOTE_TEXT\s*\}/, note_text)
+    end
+
+    def issue_id
+      "#{Issue.reference_prefix}#{@issue.iid}"
+    end
+
+    def issue_path
+      @issue.to_reference(full: true)
+    end
+
+    def note_text
+      @note&.note.to_s
+    end
+
+    def subject_base
+      "#{@issue.title} (##{@issue.iid})"
+    end
   end
 end

ee/changelogs/unreleased/2460-service-desk-email-templates.yml

+---
+title: Add support for custom email templates for service desk
+merge_request: 21745
+author:
+type: added

ee/lib/gitlab/template/service_desk_template.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Template
+    class ServiceDeskTemplate < BaseTemplate
+      class << self
+        def extension
+          '.md'
+        end
+
+        def base_dir
+          '.gitlab/service_desk_templates/'
+        end
+
+        def finder(project)
+          Gitlab::Template::Finders::RepoTemplateFinder.new(project, self.base_dir, self.extension, self.categories)
+        end
+      end
+    end
+  end
+end

ee/spec/mailers/emails/service_desk_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'email_spec'
+
+describe Emails::ServiceDesk do
+  include EmailSpec::Helpers
+  include EmailSpec::Matchers
+  include EmailHelpers
+
+  include_context 'gitlab email notification'
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let_it_be(:issue) { create(:issue, project: project) }
+  let(:template) { double(content: template_content) }
+
+  class ServiceEmailClass < BaseMailer
+    include GitlabRoutingHelper
+    include EmailsHelper
+    include Emails::ServiceDesk
+
+    helper GitlabRoutingHelper
+    helper EmailsHelper
+
+    append_view_path Rails.root.join('ee', 'app', 'views', 'notify')
+
+    # this method is implemented in Notify class, we don't need to test it
+    def reply_key
+      'test-key'
+    end
+
+    # this method is implemented in Notify class, we don't need to test it
+    def sender(author_id, params = {})
+      author_id
+    end
+
+    # this method is implemented in Notify class
+    #
+    # We do not need to test the Notify method, it is already tested in notify_spec
+    def mail_new_thread(issue, options)
+      # we need to rewrite this in order to look up templates in the correct directory
+      self.class.mailer_name = 'notify'
+
+      # this is needed for default layout
+      @unsubscribe_url = 'http://unsubscribe.example.com'
+
+      mail(options)
+    end
+    alias_method :mail_answer_thread, :mail_new_thread
+  end
+
+  shared_examples 'handle template content' do |template_key|
+    before do
+      expect(Gitlab::Template::ServiceDeskTemplate).to receive(:find)
+        .with(template_key, issue.project)
+        .and_return(template)
+    end
+
+    it 'builds the email correctly' do
+      aggregate_failures do
+        is_expected.to have_referable_subject(issue, include_project: false, reply: reply_in_subject)
+        is_expected.to have_body_text(expected_body)
+        expect(subject.content_type).to include('text/html')
+      end
+    end
+  end
+
+  shared_examples 'read template from repository' do |template_key|
+    let(:template_content) { 'custom text' }
+    let(:issue) { create(:issue, project: project)}
+
+    context 'when a template is in the repository' do
+      let(:project) { create(:project, :custom_repo, files: { ".gitlab/service_desk_templates/#{template_key}.md" => template_content }) }
+
+      it 'uses the text template from the template' do
+        is_expected.to have_body_text(template_content)
+      end
+    end
+
+    context 'when the service_desk_templates directory does not contain correct template' do
+      let(:project) { create(:project, :custom_repo, files: { ".gitlab/service_desk_templates/another_file.md" => template_content }) }
+
+      it 'uses the default template' do
+        is_expected.to have_body_text(default_text)
+      end
+    end
+
+    context 'when the service_desk_templates directory does not exist' do
+      let(:project) { create(:project, :custom_repo, files: { "other_directory/another_file.md" => template_content }) }
+
+      it 'uses the default template' do
+        is_expected.to have_body_text(default_text)
+      end
+    end
+
+    context 'when the project does not have a repo' do
+      let(:project) { create(:project) }
+
+      it 'uses the default template' do
+        is_expected.to have_body_text(default_text)
+      end
+    end
+  end
+
+  describe '.service_desk_thank_you_email' do
+    let_it_be(:reply_in_subject) { true }
+    let_it_be(:default_text) do
+      "Thank you for your support request! We are tracking your request as ticket #{issue.to_reference}, and will respond as soon as we can."
+    end
+
+    subject { ServiceEmailClass.service_desk_thank_you_email(issue.id) }
+
+    it_behaves_like 'read template from repository', 'thank_you'
+
+    context 'handling template markdown' do
+      context 'with a simple text' do
+        let(:template_content) { 'thank you, **your new issue** has been created.' }
+        let(:expected_body) { 'thank you, <strong>your new issue</strong> has been created.' }
+
+        it_behaves_like 'handle template content', 'thank_you'
+      end
+
+      context 'with an issue id and issue path placeholders' do
+        let(:template_content) { 'thank you, **your new issue:** %{ISSUE_ID}, path: %{ISSUE_PATH}' }
+        let(:expected_body) { "thank you, <strong>your new issue:</strong> ##{issue.iid}, path: #{project.full_path}##{issue.iid}" }
+
+        it_behaves_like 'handle template content', 'thank_you'
+      end
+
+      context 'with an issue id placeholder with whitespace' do
+        let(:template_content) { 'thank you, **your new issue:** %{  ISSUE_ID}' }
+        let(:expected_body) { "thank you, <strong>your new issue:</strong> ##{issue.iid}" }
+
+        it_behaves_like 'handle template content', 'thank_you'
+      end
+
+      context 'with unexpected placeholder' do
+        let(:template_content) { 'thank you, **your new issue:** %{this is issue}' }
+        let(:expected_body) { "thank you, <strong>your new issue:</strong> %{this is issue}" }
+
+        it_behaves_like 'handle template content', 'thank_you'
+      end
+    end
+  end
+
+  describe '.service_desk_new_note_email' do
+    let_it_be(:reply_in_subject) { false }
+    let_it_be(:note) { create(:note_on_issue, noteable: issue, project: project) }
+    let_it_be(:default_text) { note.note }
+
+    subject { ServiceEmailClass.service_desk_new_note_email(issue.id, note.id) }
+
+    it_behaves_like 'read template from repository', 'new_note'
+
+    context 'handling template markdown' do
+      context 'with a simple text' do
+        let(:template_content) { 'thank you, **new note on issue** has been created.' }
+        let(:expected_body) { 'thank you, <strong>new note on issue</strong> has been created.' }
+
+        it_behaves_like 'handle template content', 'new_note'
+      end
+
+      context 'with an issue id, issue path and note placeholders' do
+        let(:template_content) { 'thank you, **new note on issue:** %{ISSUE_ID}, path: %{ISSUE_PATH}: %{NOTE_TEXT}' }
+        let(:expected_body) { "thank you, <strong>new note on issue:</strong> ##{issue.iid}, path: #{project.full_path}##{issue.iid}: #{note.note}" }
+
+        it_behaves_like 'handle template content', 'new_note'
+      end
+
+      context 'with an issue id placeholder with whitespace' do
+        let(:template_content) { 'thank you, **new note on issue:** %{  ISSUE_ID}: %{ NOTE_TEXT  }' }
+        let(:expected_body) { "thank you, <strong>new note on issue:</strong> ##{issue.iid}: #{note.note}" }
+
+        it_behaves_like 'handle template content', 'new_note'
+      end
+
+      context 'with unexpected placeholder' do
+        let(:template_content) { 'thank you, **new note on issue:** %{this is issue}' }
+        let(:expected_body) { "thank you, <strong>new note on issue:</strong> %{this is issue}" }
+
+        it_behaves_like 'handle template content', 'new_note'
+      end
+    end
+  end
+end