In a monolithic application, different services are developed within same project side by side. In these kind of applications you don't need to worry about breaking the compatibility between contract interfaces since there is an invisible verifier called compiler that checks that all method calls follows the defined signature. But in case of microservices, different services are deployed in different runtimes and using different separated networks. In this scenario, any change on the contract of one service cannot be caught by the compiler since there is no typesafe connection between services.. Now breaking the compatibility between services can be really easy and hard to detect (maybe until your new version of the service is on production). In this talk we are going to explore why deploying a new version of a service might break everything in microservices architecture, and how to fix with consumer-driven contracts pattern. Video recording: https://2017.javazone.no/program/87956decfb9c467ab4f3bef24cee5064

1. Deploy microservices with Certainty
Alex Soto
@alexsotob

2. @alexsotob2
Alex Soto
Red Hat Engineer
www.lordofthejars.com
@alexsotob
Who Am I?

3. @alexsotob3
Questions

4. @alexsotob4
Any resemblance to reality is pure coincidence

5. @alexsotob5
Villains Database Application

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Villains Database Application

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Villains Database Application
Villains

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Villains Database Application
Villains Crimes

9. @alexsotob5
Villains Database Application
Villains Crimes
Give Me Information of Gru

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Villains Database Application
Villains Crimes
Give Me Crimes of GruGive Me Information of Gru

11. @alexsotob5
Villains Database Application
Villains Crimes
Give Me Crimes of GruGive Me Information of Gru

12. @alexsotob5
Villains Database Application
Villains Crimes
Give Me Crimes of GruGive Me Information of Gru

13. @alexsotob6
Villains Database Application

14. @alexsotob6
Villains Database Application

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Villains Database Application
Consumer

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Villains Database Application
Consumer Producer

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Villains Database Application
Consumer Producer

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Villains Database Application
Consumer Producer
GET /villains/Gru

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Villains Database Application
Consumer Producer
GET /crimes/GruGET /villains/Gru

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Villains Database Application
Consumer Producer
GET /crimes/Gru
[{
"name": "Moon",
"villain": "Gru",
"wiki": "/wiki/Moon"
}]
GET /villains/Gru

21. @alexsotob6
Villains Database Application
Consumer Producer
GET /crimes/Gru
[{
"name": "Moon",
"villain": "Gru",
"wiki": "/wiki/Moon"
}]
GET /villains/Gru
"name": “Gru”,
"areaOfInfluence": "World"
"crimes": [{
"name": "Moon",
"wiki": "/wiki/Moon"
}]

22. @alexsotob7
Destroying
Production Deployment

23. @alexsotob8

24. @alexsotob9
Unit Tests and Mock

25. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10

26. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10
Cheap
No setup of environment

27. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10
Cheap
No setup of environment
Fast
Mocks

28. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10
Cheap
No setup of environment
Fast
Mocks
Reliable
All local, no flaky

29. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10
Cheap
No setup of environment
Fast
Mocks
Reliable
All local, no flaky
Targeted
You know where it failed

30. @alexsotob
Advantages Disadvantages
Unit Tests (and Mocks)
10
Cheap
No setup of environment
Fast
Mocks
Reliable
All local, no flaky
Not Trustworthy
How you understand the system
Targeted
You know where it failed

31. @alexsotob11
Integration Tests

32. @alexsotob
Advantages Disadvantages
Integration Tests
12

33. @alexsotob
Advantages Disadvantages
Integration Tests
12
Trustworthy
They are real

34. @alexsotob
Advantages Disadvantages
Integration Tests
12
Trustworthy
They are real
Slow
Boot service and dependencies

35. @alexsotob
Advantages Disadvantages
Integration Tests
12
Trustworthy
They are real
Not Reliable
May fail for any external reason
Slow
Boot service and dependencies

36. @alexsotob
Advantages Disadvantages
Integration Tests
12
Trustworthy
They are real
Not Reliable
May fail for any external reason
Slow
Boot service and dependencies
Become e2e
You easily end up with e2e tests

37. @alexsotob13
Manual Tests

38. @alexsotob14
Contract Tests

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Ownership of the Contracts

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Ownership
Different Approaches
16

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> Provider Contracts
provider centric, consumers adapts all or nothing
Ownership
Different Approaches
16

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> Provider Contracts
provider centric, consumers adapts all or nothing
> Consumer Contracts
individual consumer’s needs
Ownership
Different Approaches
16

43. @alexsotob
> Provider Contracts
provider centric, consumers adapts all or nothing
> Consumer Contracts
individual consumer’s needs
> Consumer-driven Contracts
representation of a provider's obligations to all its consumers
Ownership
Different Approaches
16

44. @alexsotob17
Consumer Side
Consumer
Test

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Consumer Side
Stub Server
Consumer
Test
Expectations

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Consumer Side
Stub Server
Consumer
Test
Expectations

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Consumer Side
Stub Server
Consumer
Test
Expectations
GET /crimes/Gru

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Consumer Side
Stub Server
Consumer
Test
Expectations
GET /crimes/Gru
[{"name":...]}

49. @alexsotob17
Consumer Side
Stub Server
Consumer
Test
Expectations
GET /crimes/Gru
[{"name":...]}

50. @alexsotob17
Consumer Side
Stub Server
Consumer
Test
Expectations
GET /crimes/Gru
[{"name":...]}
Sharing

51. Provider Side
Sharing
Provider

52. Provider Side
Sharing
Test
Provider

53. Provider Side
Sharing
Test
Provider

54. Provider Side
Sharing
Test
Provider
GET /crimes/Gru
[{"name":...]}

55. Provider Side
Sharing
Test
Provider
GET /crimes/Gru
[{"name":...]}

56. Provider Side
Sharing
Test
Provider
GET /crimes/Gru
[{"name":...]}

57. @alexsotob19
Contract Tests Testing Frameworks
Consumer Driven Contracts

58. @alexsotob20

59. @alexsotob20
> Pact Foundation
Pact specification v3

60. @alexsotob20
> Pact Foundation
Pact specification v3
> Integration with several languages
JVM, Ruby, Python, Go, .Net, Swift, JS

61. @alexsotob20
> Pact Foundation
Pact specification v3
> Integration with several languages
JVM, Ruby, Python, Go, .Net, Swift, JS
> Pact Broker
Sharing contracts, API documentation, Overview of services

62. @alexsotob20
> Pact Foundation
Pact specification v3
> Integration with several languages
JVM, Ruby, Python, Go, .Net, Swift, JS
> Pact Broker
Sharing contracts, API documentation, Overview of services
> Arquillian Algeron
Arquillian ecosystem + Pact, Publishers/Retrievers, JBoss Forge

63. @alexsotob21
Building
With Certainty

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Deploy with Certainty

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Deploying Consumer
Steps on CI (Commit Stage)
23

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> Execute Build
Publish contracts as artefact version
Deploying Consumer
Steps on CI (Commit Stage)
23

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> Execute Build
Publish contracts as artefact version
> Run Head Provider Contract Tests
Check contract compatibility against version contract
Deploying Consumer
Steps on CI (Commit Stage)
23

68. @alexsotob
> Execute Build
Publish contracts as artefact version
> Run Head Provider Contract Tests
Check contract compatibility against version contract
> Run Prod Provider Contract Tests
Check contract compatibility against version contract
Deploying Consumer
Steps on CI (Commit Stage)
23

69. @alexsotob
> Execute Build
Publish contracts as artefact version
> Run Head Provider Contract Tests
Check contract compatibility against version contract
> Run Prod Provider Contract Tests
Check contract compatibility against version contract
> Release Consumer
Tag contract with environment name
Deploying Consumer
Steps on CI (Commit Stage)
23

70. @alexsotob
Deploying Provider
Steps on CI (Commit Stage)
24

71. @alexsotob
> Execute Build
Run as usual
Deploying Provider
Steps on CI (Commit Stage)
24

72. @alexsotob
> Execute Build
Run as usual
> Run Provider Contract Tests
Check contract compatibility against latest contract
Deploying Provider
Steps on CI (Commit Stage)
24

73. @alexsotob
> Execute Build
Run as usual
> Run Provider Contract Tests
Check contract compatibility against latest contract
> Run Prod Provider Contract Tests
Check contract compatibility against environment contract
Deploying Provider
Steps on CI (Commit Stage)
24

74. @alexsotob
> Execute Build
Run as usual
> Run Provider Contract Tests
Check contract compatibility against latest contract
> Run Prod Provider Contract Tests
Check contract compatibility against environment contract
> Release Provider
Deploying Provider
Steps on CI (Commit Stage)
24

75. @alexsotob25
Automate Everything
Enjoy your Vacations

76. @alexsotob26
Let’s Wind Down

77. @alexsotob
Conclusions
27

78. @alexsotob
Conclusions
27
> End To End Tests
Late feedback
Expensive change
Difficult to orchestrate

79. @alexsotob
Conclusions
27
> End To End Tests
Late feedback
Expensive change
Difficult to orchestrate
> Consumer Driven Contracts
Fail fast
Independent deployments
Improve communication

80. More Info
https://github.com/arquillian-testing-microservices/
https://www.manning.com/books/testing-java-microservices
@alexsotob