Welcome to the world of micro-apps

1. Welcome to the world of micro-apps Combing microservices, smart use cases & web applications Sander Hoogendoorn | Quby | ditisagile.nl @aahoogendoorn | Welcome to the world of micro-apps Next

2. Sander Hoogendoorn Independent dad, new agile coach, programmer, speaker, author, traveler Currently Chief Architect Quby Before CTO ANVA CTO Klaverblad Verzekeringen Global agile thoughtleader Capgemini sanderhoogendoorn.com aahoogendoorn aahoogendoorn sander@ditisagile.nl Next @aahoogendoorn | Welcome to the world of micro-apps

3. Click here @aahoogendoorn | Welcome to the world of micro-apps

4. Click here As a project manager…

5. The Times They Are a-Changin' Much faster than you think @aahoogendoorn | Welcome to the world of micro-apps Continue

6. Read more … Moore’s Law The number of transistors in a dense integrated circuit doubles approximately every two years.

7. Click here 1954

8. Click here Commodore 64

9. Read more … Amazon EC2 Then, in 2006, Amazon launched its Elastic Compute cloud (EC2) as a commercial web service that allows small companies and individuals to rent computers on which to run their own computer applications.

10. About disruption @aahoogendoorn | Welcome to the world of micro-apps Read more …

11. Complex problems require continuous exploration

12. Click here How long did it take to reach 50 million users?

13. More … Fintech challenges @aahoogendoorn | Welcome to the world of micro-apps

14. Where software development went wrong Monoliths. Why we like them, Why we hate them @aahoogendoorn | Welcome to the world of micro-apps Continue

15. Monolitths… Adding feature after feature @aahoogendoorn | Welcome to the world of micro-apps

16. Read more … Advantages A single (layered) architecture A single technology stack A single code base maintained by multiple teams

17. Read more … Disadvantages All parts are interconnected Many other systems are connected to your system Hard to change, hard to maintain Long time between releases, thereby increasing risks Slow innovation Hard to move to newer technologies Doesn’t scale very well

18. Click here Dependencies will kill you every time

19. Click here

20. Click here

21. Click here

22. Enter microservices The world of small component that do one thing only @aahoogendoorn | Welcome to the world of micro-apps Continue

23. Click here In short, the microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable by fully automated deployment machinery. There is a bare minimum of centralized management of these services, which may be written in different programming languages and use different data storage technologies. Martin Fowler Microservices @aahoogendoorn | Welcome to the world of micro-apps

24. Promises and challenges Of building microservices @aahoogendoorn | Welcome to the world of micro-apps Continue

25. Read more … Promises Features not projects Scalable Decentralized governance High performance Easy to build Easy to test Replaceable parts Individually deployable Technology independent Polyglot persistence

26. Micro-applications Building a single application versus building micro-applications @aahoogendoorn | Welcome to the world of micro-apps

27. Click here Given sufficient time any group of programmers will decide to rewrite the code.Ron Lunde @aahoogendoorn | Welcome to the world of micro-apps Lunde’s Law

28. Front end frameworks 2016

31. Click here In short, the microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable by fully automated deployment machinery. There is a bare minimum of centralized management of these services, which may be written in different programming languages and use different data storage technologies. Martin Fowler Microservices @aahoogendoorn | Welcome to the world of micro-apps

32. Product Order Customer Credit card Vendor A single application? Web ordering system

33. Click here Low availability of “resources”

34. What if we would build applications with similar characteristics as services? @aahoogendoorn | Welcome to the world of micro-apps

35. Click here In short, the microservice architectural style is an approach to developing a suite of small apps, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. These micro-apps are built around business capabilities and independently deployable by fully automated deployment machinery. There is a bare minimum of centralized management of these apps, which may be written in different programming languages and use different data storage technologies. Martin Fowler Micro-apps? @aahoogendoorn | Welcome to the world of micro-apps

36. Business process (at kite level) Select Product Select Product Show Cart Check out Cart Register Client Register CC Show Order Product Order Customer CC Vendor Apps, workers and microservices Validate CC Confirm Order (email)

37. Read more … Benefits A landscape of micro-apps Micro-apps are built around a single business capability Easy to build East to test Deploy individually Allows for frequent change without regression Functional reuse Allows for front end tech to evolve

38. Optimize for small changes @aahoogendoorn | Welcome to the world of micro-apps

39. Monolithical speed of change Monolith 1.0 Monolith 2.0 Monolith 3.0 Q1 Q2 Q3

40. Dependencies will kill you

41. Microservice speed of change Account 1.0 Product 1.0 Order 1.0 Doc 1.0 Account 20 Account 3.0 Account 4.0 Product 2.0 Product 3.0 Product 4.0 Product 5.0 Product 6..0 Order 2.0 Order 3.0 Doc 2.0 Doc 3.0 Q1 Q2 Q3

42. Click here Deploying individual micro-apps

43. Click here Microservices

44. Click here Micro-apps

45. Read more … Challenges How to model requirements? How to break up the single app? What does the architecture look like? How to handle communication between micro-apps and services? How to unify the user interface? How to handle navigation? What can a micro-app API look like?

46. Click here Lessons learned Pick your guiding principles @aahoogendoorn | Welcome to the world of micro-apps

47. Read more … Guiding principles We implement business processes We move towards a systems landscape consisting of micro- applications and microservices Requirements are modeled (in smart use cases) Micro-applications implement a single elementary business process step Micro-applications and microservices all have their own bounded context

48. Read more … Guiding principles Micro-applications do not have storage, and only talk to other micro-applications and microservices Microservices have their own storage (in MongoDB), and only talk to other microservices Communication uses a simple open protocol – JSON on REST We avoid transactions as much as possible

49. Click here Lessons learned Identify products and features @aahoogendoorn | Welcome to the world of micro-apps

50. Different levels of granularity Fish Clam Purpose Product Feature Function Too low Cloud Kite Sea Cloud Kite Sea OTOPOP

51. Smart use cases OTOPOP OTOPOP OTOPOP OTOPOP OTOPOP

52. Click here Smart use cases - microservices

53. Click here Smart use cases – micro-app

54. Click here Lessons learned Apply an evolutionary architecture @aahoogendoorn | Welcome to the world of micro-apps

55. Click here It is not the strongest of the architectures that survives, nor the most complex that survives. It is the one that is most adaptable to change. Charles Darwin @aahoogendoorn | Welcome to the world of micro-apps Evolutionary architecture

56. Service interface Process Domain Data / Services Outside world Resources Representations Use cases Flow Factories, Repositories Entities, Enums, Value objects Gateways StorageRelations Dossiers Intermediaries Storage

57. Resource (traditional Java)

58. Resource (functional Java)

59. User interface Process Domain Data / Services Outside world Pages, WebComponents Grids, Panels, Controls Use cases Flow Factories, Repositories Entities, Enums, Value objects Gateways StorageRelations Dossiers Intermediaries Storage

60. Page (Angular)

61. Use case (Typescript)

62. Repository (Typescript)

63. Service (Typescript)

64. Click here Lessons learned Separate concerns with bounded contexts @aahoogendoorn | Welcome to the world of micro-apps

65. Bounded contexts

66. Read more … Domain driven design The paradigm of designing software based on models of the underlying domain The domain model helps the business and the developers to reason about the functionality A model needs to be unified – internally consistent without contradictions The bounded context is a central pattern in domain driven design

67. Click here When you model larger domains, it becomes progressively harder to create this single unified model Instead of creating a single unified model, you create several, all valid within their bounded context Eric Evans Bounded contexts @aahoogendoorn | Welcome to the world of micro-apps

68. The single unified domain model Product Vendor Stock Order Client Delivery Payment

69. Bounded contexts Product Vendor Stock Order Client Delivery Payment Product

70. More …

71. Domain object (TypeScript)

72. Domain object (TypeScript)

73. Click here Lessons learned Avoid point-to-point contracts @aahoogendoorn | Welcome to the world of micro-apps

74. Click here Communcation breakdown Presentation Process Domain Services Outside world Pages Grids, Panels, Controls Use cases Flow Factories, Repositories Entities, Enums, Value objects Gateways ComponentsRelations Dossiers Intermediaries RatesAccounts Service interface Process Domain Data / Services Outside world Resources Representations Use cases Flow Factories, Repositories Entities, Enums, Value objects Gateways StorageRelations Dossiers Intermediaries MongoDB Micro-app Microservice

75. Point-to-point contracts Login { id: 42, firstname: Sander, lastname: H, city: Utrecht } { id, firstname, lastname, city } Account { id, firstname, lastname, city }

76. Click here Be conservative in what you send, be liberal in what you acceptJon Postel Postel’s Law @aahoogendoorn | Welcome to the world of micro-apps

77. Multiple consumers, same producer Account { id, firstname, lastname, city } Login { id, login, password } Manage user { id, firstname, lastname }

78. Click here Even if you do own the services you consume, still design your consumers to treat your services as if they were from elsewhere and vice versa Sander Hoogendoorn @aahoogendoorn | Welcome to the world of micro-apps Hoogendoorn’s Law

79. Click here Software entities (classes, modules, functions, microservices, JSON objects, API’s) should be open for extension, but closed for modificationBob Martin Open closed principle @aahoogendoorn | Welcome to the world of micro-apps

80. Click here HTTP Status Codes Cheat Sheet 1**. Hold on 2**. Here you go 3**. Go away 4**. You fucked up 5**. I fucked up

81. Click here Lessons learned Create RESTful API’s for your micro-apps @aahoogendoorn | Welcome to the world of micro-apps

82. App Use case

83. App Use case

84. Parameters

85. Click here Navigating micro-apps. Entering https://integratie.anva.live/home/#/Home Home Home Change Password Reset Password Manage Account Find Account Manage Account Find Contact Manage Contact Manage Contact View Contact Flows

86. Angular takes care of the routing @aahoogendoorn | Welcome to the world of micro-apps

87. A use case @aahoogendoorn | Welcome to the world of micro-apps

88. A use case layer supertype (Step) @aahoogendoorn | Welcome to the world of micro-apps

89. Click here Navigating micro-apps. From use case to use case Home Home Change Password Reset Password Manage Account Find Account Manage Account Find Contact Manage Contact Manage Contact View Contact Flows https://integratie.anva.live/managecontact/#/FindContact Flows.start(Flow.FindContact)

90. A list of use cases (Flow)

91. A use case provider (Flows)

92. Navigating use cases @aahoogendoorn | Welcome to the world of micro-apps

93. Click here Navigating micro-apps. Finishing a use case Flows.ok(this.contact.id) https://integratie.anva.live/home/#/Home?c=Cancel&backFrom=managecontact.FindContact Home Home Change Password Reset Password Manage Account Find Account Manage Account Find Contact Manage Contact Manage Contact View Contact Flows

94. Going back @aahoogendoorn | Welcome to the world of micro-apps

95. Click here In retrospective Some final thoughts @aahoogendoorn | Welcome to the world of micro-apps

96. Read more … Why micro-apps? All the benefits from “regular” microservices Easy to build Easy to test Flexible and frequent deployment of individual micro-apps Easy application of domain driven design Replaceable apps Allows for evolving technology

97. Never stop learning Continue @aahoogendoorn | Welcome to the world of micro-apps

98. And never forget to have fun @aahoogendoorn | Welcome to the world of micro-apps Next

99. Click here References and questions www.sanderhoogendoorn.com aahoogendoorn aahoogendoorn sander@ditisagile.nl quby.com/careers @aahoogendoorn | Welcome to the world of micro-apps We are hiring!