Compose Software Like Nature Would - RubyConf 2024

Transcript

1. Ahmed Omran COMPOSE SOFTWARE LIKE NATURE WOULD Living organisms have the incredible ability to adapt to their environment. Let’s explore together how we can create adaptable, maintainable, and resilient software with some inspiration from nature.
2. Feature Request
3. Big Ball of Mud
4. software
5. change
6. living organisms as inspiration
7. Earth: 4.5 billion YA
8. stromatolites
9. The Machinery of Life David S. Goodsell
10. small 1 μm
11. cell membrane boundaries
15. easily replaced
16. messages = colony
17. Bacterial colony
18. –Alan Kay “I thought of objects being like biological cells and/or individual computers on a network, only able to communicate with messages…”
19. Components: e.g. modules & classes Messages: e.g. methods & events Components with boundaries Compose with messages
20. • easier to reason about ( fi ts in your head) • easier to change (can be re-wri tt en) • easier to test (con fi dence when changing)
21. No Boundaries class Certi fi cate def initialize(...) # TODO: we should stop sending ten arguments to a method end # Get data from the database # Access the fi le system for a certi fi cate template # Generate a new fi le # Save the fi le to S3 # TODO: fi gure out why this is so slow end
22. Boundaries class Certi fi cate # Smaller entry point def initialize(enrollment) @enrollment = enrollment end # Limited interface def title end def subtitle end def date end private # You don't need to know what else is here! end
23. Small components class Template a tt r_reader :certi fi cate def initialize(certi fi cate) @certi fi cate = certi fi cate end def render # returns HTML end private # It's a secret end class S3File a tt r_reader :certi fi cate, :html def initialize(certi fi cate, html) @certi fi cate = certi fi cate @html = html end def save # returns the url of the fi le end private # It's a secret end
24. title subtitle date render save certi fi cate.rb template.rb s3_ fi le.rb
25. title subtitle date render refactored template.rb certi fi cate.rb save s3_ fi le.rb
26. title subtitle date render save tmp_ fi le.rb template.rb certi fi cate.rb new
28. /project |-- certi fi cate.rb |-- template.rb |-- s3_ fi le.rb … 1000 other fi les What does system do? title subtitle date render save
29. Multicellular: 1.5 billion YA
30. stove-pipe sponge
31. Mesh title subtitle date render save
32. project └── compliance └── certi fi cate ├── generator.rb ├── template.rb ├── base.rb └── s3_ fi le.rb domain speci fi c namespace coordinator
33. Compose Components module Certi fi cate class Generator # … # Compose our components def generate certi fi cate = Certi fi cate::Base.new(enrolment) html = Certi fi cate::Template.new(certi fi cate).render Certi fi cate::S3File.new(certi fi cate, html).save end # or inject the components def generate(template_strategy, saving_strategy) certi fi cate = Certi fi cate::Base.new(enrolment) html = template_strategy.new(certi fi cate).render saving_strategy.new(certi fi cate, html).save end end end
34. side-e ff ects
35. • persisting state • writing to disk • printing on a screen • making HTTP requests • raising errors • mutable data side-e ff ects / outside world
36. mutable data params[:name] # => "John" do_something_with(params) params[:name] # => "" unexpected!
37. Nervous System: ~600 million YA
38. Nerve Net
39. • nerve net: interacts with the outside world • deterministic responses
40. push side-e ff ects to the edges of our program
41. Data (e.g. sql, APIs) “Nerve Net” save (e.g. s3, device)
42. deterministic responses def add(a, b) a + b end
43. title subtitle date render save Deterministic* “Nerve Net” save (e.g. s3, device) Data (sql) Files S3 Generator
44. title subtitle date render save Deterministic* “Nerve Net” QR code delivery method save (e.g. s3, device) Data (sql) Files S3 Generator Email HTTP
45. • edges: controllers, background jobs, mailers, rake tasks, etc. • be mindful of side-e ff ects • functional/deterministic within reason
47. Run and Tumble mit.edu
48. Run and Tumble to Be tt er Design small components compose with messages push side-e ff ects to boundaries strong boundaries name & structure