Taming The Rails Monolith Mammoth

Transcript

1. Taming The Rails Monolith Mammoth
2. if ? puts "ERB is Awesome!!" else puts "HAML is Awesome!!" end # => ERB is Awesome!! # HAML is Awesome!!
3. if puts "ERB is Awesome!!" puts "ERB is Awesome!!" else puts "HAML is Awesome!!" end # => ERB is Awesome!! # HAML is Awesome!!
4. Yatish Mehta @yatish27
9. 750+ customers
10. 20 languages 100+ countries
11. 200+ Developers 5 Timezones
12. Journey
13. Monolith
14. Microservices
15. Service based Monolith
16. Monolith code smells
17. Spaghetti controllers
18. def create @issue = Issue.new(issue_params) respond_to do |format| if @issue.save format.html { redirect_to @issue, notice: ‘Success.’ } format.json { render action: 'show', status: :created, location: @issue } else format.html { render action: 'new' } format.json { render json: @issue.errors, status: :unprocessable_entity } end end end Expectation
19. def bulk_update @issues.sort! @copy = params[:copy].present? attributes = parse_params_for_bulk_issue_attributes(params) unsaved_issues = [] saved_issues = [] if @copy && params[:copy_subtasks].present? # Descendant issues will be copied with the parent task # Don't copy them twice @issues.reject! {|issue| @issues.detect {|other| issue.is_descendant_of?(other)}} end @issues.each do |orig_issue| orig_issue.reload if @copy issue = orig_issue.copy({}, :attachments => params[:copy_attachments].present?, :subtasks => params[:copy_subtasks].present? ) else issue = orig_issue end journal = issue.init_journal(User.current, params[:notes]) issue.safe_attributes = attributes call_hook(:controller_issues_bulk_edit_before_save, { :params => params, :issue => issue }) if issue.save saved_issues << issue else unsaved_issues << orig_issue end end # ... render :action => 'bulk_edit' end end Reality
20. Callback Hell
21. aasm_state :approved, :enter => Proc.new { |a| begin a.update_approved_by(User.current_user) a.approvable.generate_approval_list(:on => 'approve') unless a.skip_generate_approval_list || a.is_ultimate? rescue Exception => err a.update_attribute(:approved_by, nil) raise err end }, :after_enter => Proc.new { |a| a.update_approval_date a.update_act_as a.create_delegate_for_approval_group a.approvable.after_approval_approved(a) a.approve_approvable if a.last? }
22. Thin controllers fat models but…
23. …what if models become heavy
24. My reaction
25. Service Objects
26. What are Service Objects?
27. class ExpenseReport::Approve def initialize(document:, context:) @document = document @context = parse_context(context) end def call #.. end end Plain Old Ruby Object(PORO)
28. Defines an application’s boundary with a layer of services that establishes a set of available operations and coordinates the application’s response in each operation — Martin Fowler
29. In DDD Eric Evans uses the term Service Object to refer to objects that represent processes (as opposed to Entities and Values). DDD Service Objects are often useful to factor out behavior that would otherwise bloat Entities, it's also a useful step to patterns like Strategy and Command. — Martin Fowler
30. Contract::SubmitForApproval (contract, user) (result)
31. Structure
32. module Service class ApprovalChain::Create include Virtus.model include Service::Base attribute :document, ::Approvable attribute :template, String attribute :with_proxy, Boolean, :default => false attribute :rules, ::RuleCollection # Custom Array class CustomFieldRecordNotFound < StandardError; end def call ensure_data_source_provided! approval_chain = create_from_document(document) apply_custom_filters(approval_chain) #... end private def ensure_data_source_provided! # Add logic here end # .. other methods end end
33. module Service class ApprovalChain::Create include Virtus.model include Service::Base attribute :document, ::Approvable attribute :template, String attribute :with_proxy, Boolean, :default => false attribute :rules, ::RuleCollection # Custom Array class CustomFieldRecordNotFound < StandardError; end def call ensure_data_source_provided! approval_chain = create_from_document(document) apply_custom_filters(approval_chain) #... end private def ensure_data_source_provided! # Add logic here end # .. other methods end end
34. module Service class ApprovalChain::Create include Virtus.model include Service::Base attribute :document, ::Approvable attribute :template, String attribute :with_proxy, Boolean, :default => false attribute :rules, ::RuleCollection # Custom Array class CustomFieldRecordNotFound < StandardError; end def call ensure_data_source_provided! approval_chain = create_from_document(document) apply_custom_filters(approval_chain) #... end private def ensure_data_source_provided! # Add logic here end # .. other methods end end
35. module Service class ApprovalChain::Create include Virtus.model include Service::Base attribute :document, ::Approvable attribute :template, String attribute :with_proxy, Boolean, :default => false attribute :rules, ::RuleCollection # Custom Array class CustomFieldRecordNotFound < StandardError; end def call ensure_data_source_provided! approval_chain = create_from_document(document) apply_custom_filters(approval_chain) #... end private def ensure_data_source_provided! # Add logic here end # .. other methods end end
36. module Service class ApprovalChain::Create include Virtus.model include Service::Base attribute :document, ::Approvable attribute :template, String attribute :with_proxy, Boolean, :default => false attribute :rules, ::RuleCollection # Custom Array class CustomFieldRecordNotFound < StandardError; end def call ensure_data_source_provided! approval_chain = create_from_document(document) apply_custom_filters(approval_chain) #... end private def ensure_data_source_provided! # Add logic here end # .. other methods end end
37. # /app/services/service/base.rb module Service::Base def self.call(*args) wrap_in_transaction_if_requested do new(*args).call end end #... end Service::ApprovalChain::Create.call({ document: document, with_proxy: true, ... })
38. app !"" services #"" service $ #"" approval_list $ #"" supplier $ #"" call_out $ #"" contract $ #"" expense_report $ #"" invoices $ #"" pay $ #"" sign_provider $ !"" base.rb !"" service.rb File Structure
39. Service::Noun::Verb Naming convention Service::SignatureProvider::RequestToken Service::Contract::SubmitForApproval
40. Some actions in a system warrant a Service Object to encapsulate their operation. I reach for Service Objects when an action meets one or more of these criteria: • The action is complex (e.g. closing the books at the end of an accounting period) • The action reaches across multiple models (e.g. an e-commerce purchase using Order, CreditCard and Customer objects) • The action interacts with an external service (e.g. posting to social networks) • The action is not a core concern of the underlying model (e.g. sweeping up outdated data after a certain time period). • There are multiple ways of performing the action (e.g. authenticating with an access token or password). This is the Gang of Four Strategy pattern. — Bryan Helmkamp
41. The Zen of Service Objects
42. Do one thing & Do it well
43. Be Stateless
44. Be Immutable
45. Clear is better than clever
46. Fail for validations, but handle exceptions
47. Next steps
48. Thank You
49. References http://martinfowler.com/eaaCatalog/serviceLayer.html http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat- activerecord-models/ https://gist.github.com/blaix/5764401 http://rails-refactoring.com/