Microservices, Boounded Contexts, and Everything in Between

Transcript

1. vladikk doit-intl.com MICROSERVICES BOUNDED CONTEXTS AND EVERYTHING IN BETWEEN
2. vladikk doit-intl.com ”95% of the words are spent extolling the benefits of “modularity” and that little, if anything, is said about how to achieve it” Glenford J. Myers
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4. vladikk doit-intl.com “MICROSERVICES FTW!!!!!!!!1” Me @ Internovus
5. vladikk doit-intl.com “MICROSERVICES FTW!!!!!!!!1” Me @ Internovus
6. vladikk doit-intl.com ”95% of the words are spent extolling the benefits of “modularity” and that little, if anything, is said about how to achieve it” Glenford J. Myers
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9. vladikk doit-intl.com Decomposi)on Strategies Microservices Design Heuris)cs
10. vladikk doit-intl.com Decomposi)on Strategies Microservices Design Heuris)cs
11. vladikk doit-intl.com Decomposi)on Strategies Microservices Design Heuris)cs
12. vladikk doit-intl.com INTERNOVUS 01 BUSINESS DOMAIN
13. vladikk doit-intl.com Your Product Marketing Strategy Creatives Campaigns Sales Agents Optimization Profits
14. vladikk doit-intl.com DECOMPOSITION 02 STRATEGIES
15. vladikk doit-intl.com Bounded Contexts
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17. vladikk doit-intl.com Domain Expert Software Developer
18. vladikk doit-intl.com Business Domain Expert Software Developer ??? !!! Ubiquitous Language
19. vladikk doit-intl.com Campaigns Sales Agents Your Product Marketing Strategy Creatives Optimization Profits
20. vladikk doit-intl.com Sales Agent Campaign Manager ??? !!! LEAD?
21. vladikk doit-intl.com Conflicting models Different contexts Dividing the language/model Bounded Context
22. vladikk doit-intl.com MarkeCng Sales Lead Lead Funnel Campaign Placement Landing Page Agency Insertion Order Message Campaign Proposition Desk Conversion Contact CDR Bounded Contexts
23. vladikk doit-intl.com MarkeCng Service Sales Service DecomposiCon Strategy #1: Bounded Contexts
24. vladikk doit-intl.com MarkeCng Sales Commissions Desks Sales Optimization CRM Telephony Creative Catalog Contracts Billing Campaign Management Identity & Access Ads Optimization Identity & Access
25. vladikk doit-intl.com Business (Sub)Domains
26. vladikk doit-intl.com Business Domain: Customer Acquisi)on Bounded Context: Marke)ng Bounded Context: Sales Subdomain: Crea)ve Catalog Subdomain: Campaigns Mngmt Subdomain: Ads Op)miza)on Subdomain: Contracts Mngmt Subdomain: CRM Subdomain: Sales Op)miza)on Subdomain: Commissions Subdomain: Desks Mngmt
27. vladikk doit-intl.com DecomposiCon Strategy #2: Subomains Campaign Management Service Content Catalog Service Desks Management Service CRM Service Users Service Billing Service
28. vladikk doit-intl.com Business EnCCes and Processes
29. vladikk doit-intl.com MarkeCng Creative Catalog Contracts Billing Campaign Management Identity & Access Optimization Campaign Management Campaign Placement Funnel Banner Landing Page Website Zone Asset Publisher Target Market
30. vladikk doit-intl.com DecomposiCon Strategy #3: EnCCes Website Asset Target Market Broker Distribu)on Customer
31. vladikk doit-intl.com DecomposiCon Strategies Bounded Contexts Subdomains Business Entities and Processes
32. vladikk doit-intl.com SHOW ME THE MICROSERVICES!
33. vladikk doit-intl.com MarkeCng Creative Catalog Contracts Billing Campaign Management Identity & Access Optimization Campaign Management Campaign Placement Funnel Banner Landing Page Website Zone Asset Publisher Target Market Campaign Website Placement Funnel Bounded Contexts? Subdomains? EnCCes?
34. vladikk doit-intl.com Bounded Contexts == Microservices ?
35. vladikk doit-intl.com Sales Agent Campaign Manager ??? !!! LEAD?
36. vladikk doit-intl.com MarkeCng Sales Lead Lead Funnel Campaign Placement Landing Page Agency Insertion Order Message Campaign Proposition Desk Conversion Contact CDR
37. vladikk doit-intl.com MarkeCng Sales Commissions Desks Optimization CRM Telephony Creative Catalog Contracts Billing Campaign Management Identity & Access Optimization Identity & Access Lead Lead
38. vladikk doit-intl.com MarkeCng Creative Catalog Campaign Management Optimization Lead Sales Commissions Optimization CRM Lead Desks Telephony Support Contracts Billing Identity & Access
39. vladikk doit-intl.com Bounded Contexts Decomposi)on #1 Bounded Contexts Decomposi)on #2 Bounded Contexts Decomposi)on #3
40. vladikk doit-intl.com Bounded Context Consistency boundary of the language / model Define the biggest valid monoliths Required decomposition boundary
41. vladikk doit-intl.com Bounded Contexts == Microservices? No
42. vladikk doit-intl.com Campaign Management Campaign Placement Funnel Banner Landing Page Website Zone Asset Publisher Target Market Campaign Website Placement Funnel MarkeCng Creative Catalog Contracts Billing Campaign Management Identity & Access Optimization Bounded Contexts? No Subdomains? EnCCes?
43. vladikk doit-intl.com MICROSERVICES 03
44. vladikk doit-intl.com “A service is a unit of functionality exposed to the world” - Juval Lowy “A mechanism to enable access to one or more capabilities, where the access is provided using a prescribed interface” - OASIS Service
45. vladikk doit-intl.com Service Interface “Any mechanism for getting data in or out of the service” - Randy Shoup
46. vladikk doit-intl.com Service Interface Asynchronous: • Producing events • Consuming events Synchronous: • Request / Response • Bulk ETL
47. vladikk doit-intl.com Service Interface “Any mechanism for getting data in or out of the service” - Randy Shoup
48. vladikk doit-intl.com Service Interface
49. vladikk doit-intl.com Services ➜ Microservice
50. vladikk doit-intl.com A microservice is a service with a micro interface
51. vladikk doit-intl.com Microservice = Microinterface Reducing coupling between services Limits reasons for change Easier to understand Better fault isolation More autonomy between services
52. vladikk doit-intl.com Microservice = Microinterface Reducing coupling between services Limits reasons for change Easier to understand Better fault isolation More autonomy between services
53. vladikk doit-intl.com Microservice & Databases Microservices should own its database No external access Access through Microservice’s API only Database = infinite interface!
54. vladikk doit-intl.com 1 Method = Perfect Microservice !!??
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59. vladikk doit-intl.com STAFF ONLY STAFF ONLY
60. vladikk doit-intl.com The threshold upon which a system can be decomposed into microservices is defined by the use cases of the system that the microservices are a part of.
61. vladikk doit-intl.com Monolith Microservices Distributed Monolith Cost of Change
62. vladikk doit-intl.com Big Ball Of Mud Bounded Contexts Microservices Distributed Big Ball Of Mud Avg. Service Size
63. vladikk doit-intl.com Campaign Management Campaign Placement Funnel Banner Landing Page Website Zone Asset Publisher Target Market Campaign Website Placement Funnel Subdomains? EnCCes?
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65. vladikk doit-intl.com ”Global complexity … the complexity of the overall structure of a program or system. I.e., the degree of association or interdependence among the major pieces of a program” Glenford J. Myers
66. vladikk doit-intl.com ”Global complexity … the complexity of the overall structure of a program or system. I.e., the degree of association or interdependence among the major pieces of a program” Glenford J. Myers Composite / Structured Design, 1978
67. vladikk doit-intl.com When you design a system…, then if the features can be broken into … loosely bound groups of rela>vely closely bound features, then that division is a good thing to be made a part of the design. This is just good engineering. Tim Berners-Lee Principles of design, 1998
68. vladikk doit-intl.com Services + Good Engineering = Microservices
69. vladikk doit-intl.com Its is not only necessary to make sure your own system is designed to be made of modular parts. It is also necessary to realize that your own system … should always be designed to be a part of another larger system. Tim Berners-Lee Principles of design, 1998
70. vladikk doit-intl.com A major part of this paper will be concerned with the ques>on of how good modularity can be achieved, that is, how modules can be chosen so as to minimize the connec5ons between them. Barbara Liskov A design methodology for reliable soIware systems, 1972
71. vladikk doit-intl.com A microservice is a service with a micro interface. The threshold upon which a system can be decomposed into microservices is defined by the use cases of the system that the microservices are a part of.
72. vladikk doit-intl.com A microservice is a service with a micro interface. The threshold upon which the system can be decomposed is defined by the use cases of the system that the microservices are a part of. …how to evaluate?
73. vladikk doit-intl.com DESIGN 04 HEURISTICS
74. vladikk doit-intl.com HeurisCc #1: Decompose to Bounded Contexts Do not implement conflicting models in the same service. Always decompose to Bounded Contexts.
75. vladikk doit-intl.com HeurisCc #2: Don’t First Law of Distributed Object Design: “Don’t distribute your objects” MarCn Fowler
76. vladikk doit-intl.com HeurisCc #2: Don’t Benefits Addi)onal Complexity
77. vladikk doit-intl.com MONOLITH SYSTEM DESIGN THAT UNDERMINES DELIVERY OF FUNCTIONAL OR NON-FUNCTIONAL REQUIREMENTS
78. vladikk doit-intl.com HeurisCc #2: Don’t Benefits Addi)onal Complexity
79. vladikk doit-intl.com HeurisCc #2: Don’t Benefits Addi)onal Complexity
80. vladikk doit-intl.com Core Supporting Generic
81. vladikk doit-intl.com Generic Subdomains No competitive advantage Everybody is implementing in the same way Complex business logic
82. vladikk doit-intl.com MarkeCng Sales Commissions Desks Optimization CRM Telephony Creative Catalog Contracts Billing Campaign Management Identity & Access Optimization Identity & Access Generic
83. vladikk doit-intl.com HeurisCc #3: Buy/Adopt Generic Subdomains Your System 3rd party product
84. vladikk doit-intl.com HeurisCc #3: Buy/Adopt Generic Subdomains Your System 3rd party product An)-Corrup)on Layer
85. vladikk doit-intl.com Core Subdomains Inventing something new Optimizing existing paractices Competitive advantage Complex business logic Change often
86. vladikk doit-intl.com MarkeCng Sales Commissions Desks Sales Optimization CRM Telephony Creative Catalog Contracts Billing Campaign Management Identity & Access Ad Optimization Identity & Access Generic Core
87. vladikk doit-intl.com Core Subdomains Inventing something new Optimizing existing paractices Competitive advantage Complex business logic Change often
88. vladikk doit-intl.com HeurisCc #4: Core Subdomains - Don’t Rush Adhere to subdomain’s boundaries. Decompose further only when you acquire domain knowledge.
89. vladikk doit-intl.com SupporCng Subdomains No competitive advantage Support the Core Subdomains Can’t be bought / adopted Simple business logic
90. vladikk doit-intl.com MarkeCng Sales Commissions Desks Sales Optimization CRM Telephony Creative Catalog Contracts Billing Campaign Management Identity & Access Ad Optimization Identity & Access Generic Core Supporting
91. vladikk doit-intl.com SupporCng Subdomains No competitive advantage Support the Core Subdomains Can’t be bought / adopted Simple business logic
92. vladikk doit-intl.com HeurisCc #5: SupporCng Subdomains - Safe Safe to decompose beyond the subdomain’s boundaries.
93. vladikk doit-intl.com Core Supporting Generic
94. vladikk doit-intl.com HeurisCc #6: Evaluate Consistency Requirements Method A Method B
95. vladikk doit-intl.com HeurisCc #6: Evaluate Consistency Requirements Concurrency control? - Same service Method A Method B Service A
96. vladikk doit-intl.com HeurisCc #6: Evaluate Consistency Requirements Read last write? - Two services, synchronous communication Service A Method A Service B Method B Sync call
97. vladikk doit-intl.com HeurisCc #6: Evaluate Consistency Requirements Eventual consistency? - Two services, asynchronous communication Service A Method A Service B Method B Asynchronous Communication
98. vladikk doit-intl.com HeurisCc #6: Evaluate Consistency Requirements Concurrency control? - Same service Read last write? - Two services, sync communication Eventual consistency? - Two services, async communication
99. vladikk doit-intl.com Service A Method A Service B Method B Asynchronous Communication
100. vladikk doit-intl.com HeurisCc #7: Public / Private Events Service Event Type 1 Event Type 2 Event Type 3 Event Type 4 Event Type 5 Event Type 6 Event Type 1000 …
101. vladikk doit-intl.com HeurisCc #7: Public / Private Events Service Event Type 1 Event Type 2 Event Type 3 Event Type 4 Event Type 5 Event Type 6 Private event types (Implementation details) } Event Type 1000 …
102. vladikk doit-intl.com HeurisCc #7: Public / Private Events Service Event Type 1 Event Type 2 Event Type 3 Event Type 4 Event Type 5 Event Type 6 Event Type 1000 … Private event types (Implementation details) }Public event types (Public interface) }
103. vladikk doit-intl.com Service EmailChanged PhoneNumberChanged AddressChanged ContactDetailsChanged HeurisCc #7: Public / Private Events
104. vladikk doit-intl.com Service EmailChanged PhoneNumberChanged AddressChanged ContactDetailsChanged Private event types (Implementation details) } Public event type (Public interface) } HeurisCc #7: Public / Private Events
105. vladikk doit-intl.com HeurisCc #7: Public / Private Events Events? Domain Events State Change Events
106. vladikk doit-intl.com HeurisCc #7: Public / Private Events Events? Domain Events State Change Events Private Public
107. vladikk doit-intl.com HeurisCc #8: Make Events Explicit Eliminate ambiguity
108. vladikk doit-intl.com HeurisCc #8: Make Events Explicit Service AgentAssignedToLead AgentAssignedToLead AgentAssignedToLead
109. vladikk doit-intl.com HeurisCc #8: Make Events Explicit Service AgentAssignedToLead AgentUnassignedToLead AgentAssignedToLead
110. vladikk doit-intl.com HeurisCc #9: Evaluate Reasons for Change Service A Service B
111. vladikk doit-intl.com Same reasons for change? Same rate of change? Can be decoupled? Should be the same service? HeurisCc #9: Evaluate Reasons for Change
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113. vladikk doit-intl.com HeurisCc #10: Evaluate Services’ “Doors”
114. vladikk doit-intl.com HeurisCc #10: Evaluate Services’ “Doors” STAFF ONLY STAFF ONLY
115. vladikk doit-intl.com WRAP UP 05
116. vladikk doit-intl.com 1. A service is a unit of func)onality exposed to the world through its public interface. 2. A microservice is a service with micro interface 3. The “micro-interface” is rela)ve to the use cases of the system that the service is a part of
117. vladikk doit-intl.com Heuris)c #1: Always decompose to Bounded Contexts Heuris)c #2: Don’t go further, unless you have to Heuris)c #3: Buy/adopt generic subdomains Heuris)c #4: Core subdomains - don’t rush Heuris)c #5: Suppor)ng subdomains can be decomposed early
118. vladikk doit-intl.com Heuris)c #6: Evaluate Consistency Requirements Heuris)c #7: Private / Public Events Heuris)c #8: Explicitly Define Events Heuris)c #9: Evaluate Reasons for Change Heuris)c #10: Evaluate Services’ “Doors”
119. vladikk doit-intl.com Big Ball Of Mud Bounded Contexts Microservices Distributed Big Ball Of Mud Avg. Service Size
120. vladikk doit-intl.com Bibliography 1. A Design Methodology for Reliable Soeware Systems, Barbara Liskov 2. Designing Autonomous Teams and Services, Nick Tune & Scoh Millet 3. Composite/Structured Design, Glenford Myers 4. Domain-Driven Design: Tackling Complexity in the Heart of Soeware, Eric Evans 5. Emerging Boundaries, Mathias Veraes 6. Implemen)ng Domain-Driven Design, Vaughn Vernon 7. Enterprise Integra)on Paherns, Gregory Hohpe, at al 8. Long Sad Story of Microservices, Greg Young 9. Managing Data in Microservices, Randy Shoup 10. Microservices, At Last Some Boundaries, Eric Evans 11. On the Criteria to be Used in Decomposing Systems Into Modules, David Parnas 12. Paherns of Enterprise Applica)on Architecture, Mar)n Fowler, at al 13. Principles of Design, Tim Berners-Lee 14. Programming WCF Services, Juval Lowy 15. What Every Programmer Should Know About Object Oriented Design, Melir Page-Jones
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