The Shape of a Service Object

Transcript

1. The SHAPE OF A Service object Ivan Nemytchenko EuRuKo 2024
2. Who am I and why am I here - Age: on Rails since 2006 - Current role: CTO at setyl.com - Passion: Complexity organization optimization - At my agency: RBBR Limited - Methodology: “Painless Rails“ - My twittter: x.com/inemation - My stuff: taplink.cc/inem
3. Service object is a De facto standard Standard building block for complexity management
4. Service object is a FAKE concept
5. The shape
6. COde TOPOLOGY notation
7. Objects
8. Objects with methods
9. A method with arguments
10. Instance variables
11. Instance variables
12. Returning results
13. Private methods
14. Classes A spawning platform
15. Classes A spawning platform
16. same topology Object & classes have the
18. The shape
19. Service Objects in the wild
20. Service Objects in the wild
21. Service Objects in the wild
22. Service Objects in the wild
23. Service Objects in the wild
24. Service Objects in the wild
25. Service Objects in the wild
26. The Definition of service object They just do stuff
27. The Definition of service object They just do stuff and they all look the same
28. The shape of A service object
29. Serious guys are doing it too
30. The shape of A service object
31. The shape of A service object
32. Complexity Grows inward
34. Painless RAILS 1. Layered Architecture 2. Abstractions of a Single Level 3. Building blocks per type of work done by code
35. Splitting code by the types of work done by IT
42. Let’s find its own “shelf” for Every type of work
44. account_locked? fi rst_login_from_new_ip? User
46. UserMutator record_login_fact handle_failed_login
48. AuthController create
50. UserService authenticate
52. User User AuthenticationService UserMutator AuthController AuthController UserService
54. EASIER to test
55. Modularity
56. LAYERed ARCHITECTURE
57. Services Mutators Models Controller actions LAYERed ARCHITECTURE
58. Wait, they still could be service objects!
62. UserAuthenticationService LoginEventRecorder FailedLoginHandler UserBusinessRules UserMutator UserService User + service objects TYPES OF WORK
63. UserAuthenticationService LoginEventRecorder FailedLoginHandler UserBusinessRules UserMutator UserService User + service objects TYPES OF WORK
64. Services Managers Mutators Business Rules Forms Building blocks per TYPES OF WORK
65. Services Mutators Models Controller actions LAYERed ARCHITECTURE
66. The SHAPE AND THE MISSING IDEA OF A Service object
67. Service object === shape
68. Service object is an empty concept
69. Services Mutators Models Controller actions Service Objects LAYERed ARCHITECTURE
70. FowLER & Evans
71. FowLER & Evans Service Layer Domain Services
72. fowler Patterns of Enterprise Application Architecture
73. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic
74. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary
75. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations
76. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects
77. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions
78. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic
79. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic • coordinates responses
80. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic • coordinates responses
81. Martin fowler Patterns of Enterprise Application Architecture Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic • coordinates responses
82. Eric Evans Domain-Driven Design
83. Eric Evans Domain-Driven Design Domain Services: • are stateless
84. Eric Evans Domain-Driven Design Domain Services: • are stateless • named for an activity rather than an entity
85. Eric Evans Domain-Driven Design Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations
86. Eric Evans Domain-Driven Design Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations • are distinct from technical services
87. Eric Evans Domain-Driven Design Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations • are distinct from technical services
88. Eric Evans Domain-Driven Design Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations • are distinct from technical services • may have side effects
89. The message being sent to us Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations • are distinct from technical services • may have side effects Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic
90. The message being sent to us Domain Services: • are stateless • named for an activity rather than an entity • represent signi fi cant business domain processes/operations • are distinct from technical services • may have side effects Service layer: • separates domain logic from application logic • de fi nes application boundary • sets available operations • coordinates domain objects • controls transactions • encapsulates the app's business logic 🤔
91. Technical services == Application logic? Service Layer consists of Domain Services, which are: • are stateless • named for an activity rather than an entity • represent signi fi cant operations • coordinate domain objects & control transactions • may have side effects The message being sent to us 🤔
92. The message being sent to us is stateless named for an activity, not entity represents business operations coordinates domain objects controls transactions should theoretically have side effects no application logic Domain Service:
93. The message being sent to us Domain Service: is stateless named for an activity, not entity represents business operations coordinates domain objects controls transactions should theoretically have side effects no application logic
94. Fowler-Evans Service Ruler!! Domain Service: is stateless named for an activity, not entity represents business operations coordinates domain objects controls transactions should theoretically have side effects no application logic
95. Recommendations • Don’t use the term Service Object • Don’t use Service Objects • Split your code by the types of work done by it • Types of work → Types of building blocks • Measure your services with Fowler-Evans ruler!
96. https://Rails.services Ivan Nemytchenko EuRuKo 2024