Microservices, Boounded Contexts, and Everything in Between

Transcript

1. vladikk doit-intl.com
   MICROSERVICES
   BOUNDED CONTEXTS
   AND EVERYTHING IN BETWEEN
   

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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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3. vladikk doit-intl.com
   

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4. vladikk doit-intl.com
   “MICROSERVICES FTW!!!!!!!!1”
   Me @ Internovus
   

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5. vladikk doit-intl.com
   “MICROSERVICES FTW!!!!!!!!1”
   Me @ Internovus
   
   

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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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7. vladikk doit-intl.com
   

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8. vladikk doit-intl.com
   

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9. vladikk doit-intl.com
   Decomposi)on Strategies
   Microservices
   Design Heuris)cs
   

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10. vladikk doit-intl.com
    Decomposi)on Strategies
    Microservices
    Design Heuris)cs
    

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11. vladikk doit-intl.com
    Decomposi)on Strategies
    Microservices
    Design Heuris)cs
    

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12. vladikk doit-intl.com
    INTERNOVUS
    01
    BUSINESS DOMAIN
    

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13. vladikk doit-intl.com
    Your Product Marketing
    Strategy
    Creatives Campaigns Sales
    Agents
    Optimization
    Profits
    

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14. vladikk doit-intl.com
    DECOMPOSITION
    02
    STRATEGIES
    

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15. vladikk doit-intl.com
    Bounded Contexts
    

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16. vladikk doit-intl.com
    

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17. vladikk doit-intl.com
    Domain Expert
    Software Developer
    

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18. vladikk doit-intl.com
    Business Domain Expert
    Software Developer
    ???
    !!!
    Ubiquitous Language
    

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19. vladikk doit-intl.com
    Campaigns Sales
    Agents
    Your Product Marketing
    Strategy
    Creatives
    Optimization
    Profits
    

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20. vladikk doit-intl.com
    Sales Agent
    Campaign Manager
    ???
    !!!
    LEAD?
    

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21. vladikk doit-intl.com
    Conflicting models
    Different contexts
    Dividing the language/model
    Bounded Context
    

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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
    

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23. vladikk doit-intl.com
    MarkeCng
    Service
    Sales
    Service
    DecomposiCon Strategy #1: Bounded Contexts
    

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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
    

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25. vladikk doit-intl.com
    Business (Sub)Domains
    

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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
    

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27. vladikk doit-intl.com
    DecomposiCon Strategy #2: Subomains
    Campaign
    Management
    Service
    Content
    Catalog
    Service
    Desks
    Management
    Service
    CRM
    Service
    Users
    Service
    Billing
    Service
    

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28. vladikk doit-intl.com
    Business EnCCes and Processes
    

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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
    

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30. vladikk doit-intl.com
    DecomposiCon Strategy #3: EnCCes
    Website Asset Target Market
    Broker Distribu)on Customer
    

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31. vladikk doit-intl.com
    DecomposiCon Strategies
    Bounded Contexts
    Subdomains
    Business Entities and Processes
    

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32. vladikk doit-intl.com
    SHOW ME THE
    MICROSERVICES!
    

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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?
    

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34. vladikk doit-intl.com
    Bounded Contexts == Microservices ?
    

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35. vladikk doit-intl.com
    Sales Agent
    Campaign Manager
    ???
    !!!
    LEAD?
    

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36. vladikk doit-intl.com
    MarkeCng
    Sales
    Lead Lead
    Funnel
    Campaign
    Placement
    Landing Page
    Agency Insertion Order
    Message
    Campaign
    Proposition
    Desk
    Conversion
    Contact
    CDR
    

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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
    

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38. vladikk doit-intl.com
    MarkeCng
    Creative
    Catalog
    Campaign
    Management
    Optimization
    Lead
    Sales
    Commissions
    Optimization
    CRM Lead
    Desks
    Telephony
    Support
    Contracts
    Billing
    Identity & Access
    

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39. vladikk doit-intl.com
    Bounded Contexts
    Decomposi)on #1
    Bounded Contexts
    Decomposi)on #2
    Bounded Contexts
    Decomposi)on #3
    

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40. vladikk doit-intl.com
    Bounded Context
    Consistency boundary of the language / model
    Define the biggest valid monoliths
    Required decomposition boundary
    

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41. vladikk doit-intl.com
    Bounded Contexts == Microservices? No
    

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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?
    

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43. vladikk doit-intl.com
    MICROSERVICES
    03
    

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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
    

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45. vladikk doit-intl.com
    Service Interface
    “Any mechanism for getting data in or out of the service”
    - Randy Shoup
    

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46. vladikk doit-intl.com
    Service Interface
    Asynchronous:
    • Producing events
    • Consuming events
    Synchronous:
    • Request / Response
    • Bulk ETL
    

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47. vladikk doit-intl.com
    Service Interface
    “Any mechanism for getting data in or out of the service”
    - Randy Shoup
    

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48. vladikk doit-intl.com
    Service Interface
    

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49. vladikk doit-intl.com
    Services ➜ Microservice
    

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50. vladikk doit-intl.com
    A microservice is a service with a micro interface
    

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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
    

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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
    

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53. vladikk doit-intl.com
    Microservice & Databases
    Microservices should own its database
    No external access
    Access through Microservice’s API only
    Database = infinite interface!
    

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54. vladikk doit-intl.com
    1 Method = Perfect Microservice !!??
    

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55. vladikk doit-intl.com
    

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56. vladikk doit-intl.com
    

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57. vladikk doit-intl.com
    

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58. vladikk doit-intl.com
    

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59. vladikk doit-intl.com
    STAFF
    ONLY
    STAFF
    ONLY
    

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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.
    

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61. vladikk doit-intl.com
    Monolith Microservices Distributed
    Monolith
    Cost
    of
    Change
    

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62. vladikk doit-intl.com
    Big Ball Of Mud Bounded
    Contexts
    Microservices Distributed
    Big Ball Of Mud
    Avg.
    Service
    Size
    

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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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64. vladikk doit-intl.com
    

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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
    

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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
    

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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
    

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68. vladikk doit-intl.com
    Services + Good Engineering = Microservices
    

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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
    

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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
    

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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.
    

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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?
    

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73. vladikk doit-intl.com
    DESIGN
    04
    HEURISTICS
    

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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.
    

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75. vladikk doit-intl.com
    HeurisCc #2: Don’t
    First Law of Distributed Object Design:
    “Don’t distribute your objects”
    MarCn Fowler
    

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76. vladikk doit-intl.com
    HeurisCc #2: Don’t
    Benefits
    Addi)onal
    Complexity
    

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77. vladikk doit-intl.com
    MONOLITH
    SYSTEM DESIGN THAT UNDERMINES DELIVERY OF
    FUNCTIONAL OR NON-FUNCTIONAL REQUIREMENTS
    

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78. vladikk doit-intl.com
    HeurisCc #2: Don’t
    Benefits
    Addi)onal
    Complexity
    

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79. vladikk doit-intl.com
    HeurisCc #2: Don’t
    Benefits Addi)onal
    Complexity
    

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80. vladikk doit-intl.com
    Core
    Supporting
    Generic
    

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81. vladikk doit-intl.com
    Generic Subdomains
    No competitive advantage
    Everybody is implementing in the same way
    Complex business logic
    

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82. vladikk doit-intl.com
    MarkeCng
    Sales
    Commissions
    Desks
    Optimization
    CRM
    Telephony
    Creative
    Catalog
    Contracts
    Billing
    Campaign
    Management
    Identity & Access
    Optimization
    Identity & Access
    Generic
    

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83. vladikk doit-intl.com
    HeurisCc #3: Buy/Adopt Generic Subdomains
    Your
    System
    3rd party
    product
    

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84. vladikk doit-intl.com
    HeurisCc #3: Buy/Adopt Generic Subdomains
    Your
    System
    3rd party
    product
    An)-Corrup)on Layer
    

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85. vladikk doit-intl.com
    Core Subdomains
    Inventing something new
    Optimizing existing paractices
    Competitive advantage
    Complex business logic
    Change often
    

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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
    

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87. vladikk doit-intl.com
    Core Subdomains
    Inventing something new
    Optimizing existing paractices
    Competitive advantage
    Complex business logic
    Change often
    

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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.
    

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89. vladikk doit-intl.com
    SupporCng Subdomains
    No competitive advantage
    Support the Core Subdomains
    Can’t be bought / adopted
    Simple business logic
    

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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
    

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91. vladikk doit-intl.com
    SupporCng Subdomains
    No competitive advantage
    Support the Core Subdomains
    Can’t be bought / adopted
    Simple business logic
    

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92. vladikk doit-intl.com
    HeurisCc #5: SupporCng Subdomains - Safe
    Safe to decompose beyond the subdomain’s
    boundaries.
    

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93. vladikk doit-intl.com
    Core
    Supporting
    Generic
    

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94. vladikk doit-intl.com
    HeurisCc #6: Evaluate Consistency Requirements
    Method A Method B
    

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95. vladikk doit-intl.com
    HeurisCc #6: Evaluate Consistency Requirements
    Concurrency control? - Same service
    Method A Method B
    Service A
    

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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
    

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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
    

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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
    

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99. vladikk doit-intl.com
    Service A
    Method A
    Service B
    Method B
    Asynchronous
    Communication
    

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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
     …
     

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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
     …
     

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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)
     }
     

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103. vladikk doit-intl.com
     Service
     EmailChanged
     PhoneNumberChanged
     AddressChanged
     ContactDetailsChanged
     HeurisCc #7: Public / Private Events
     

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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
     

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105. vladikk doit-intl.com
     HeurisCc #7: Public / Private Events
     Events?
     Domain
     Events
     State Change
     Events
     

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106. vladikk doit-intl.com
     HeurisCc #7: Public / Private Events
     Events?
     Domain
     Events
     State Change
     Events
     Private Public
     

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107. vladikk doit-intl.com
     HeurisCc #8: Make Events Explicit
     Eliminate ambiguity
     

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108. vladikk doit-intl.com
     HeurisCc #8: Make Events Explicit
     Service
     AgentAssignedToLead
     AgentAssignedToLead
     AgentAssignedToLead
     

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109. vladikk doit-intl.com
     HeurisCc #8: Make Events Explicit
     Service
     AgentAssignedToLead
     AgentUnassignedToLead
     AgentAssignedToLead
     

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110. vladikk doit-intl.com
     HeurisCc #9: Evaluate Reasons for Change
     Service A Service B
     

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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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112. vladikk doit-intl.com
     

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113. vladikk doit-intl.com
     HeurisCc #10: Evaluate Services’ “Doors”
     

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114. vladikk doit-intl.com
     HeurisCc #10: Evaluate Services’ “Doors”
     STAFF
     ONLY
     STAFF
     ONLY
     

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115. vladikk doit-intl.com
     WRAP UP
     05
     

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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
     

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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
     

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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”
     

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119. vladikk doit-intl.com
     Big Ball Of Mud Bounded
     Contexts
     Microservices Distributed
     Big Ball Of Mud
     Avg.
     Service
     Size
     

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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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121. https://bit.ly/2ptJ5fS
     THANK
     YOU!
     @vladikk
     vladikk.com
     https://bit.ly/31nSD9c
     http://careers.doit-intl.com
     

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122. QUESTIONS?
     @vladikk vladikk.com
     

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