Software contracts and microservices
•
0 likes•19 views
The rise of micro-service architectures offers the promise of a more agile software development process. Software systems will be made up of many collaborating components which are developed, deployed and operated by distributed teams and organizations. But how can we avoid a recurring configuration nightmare (c.f. DLL hell) and ensure that we benefit from the promised flexibility, rather than creating a fragile, distributed monolith? Contract testing offers an excellent solution. Participants will be able to: - Explain why contract testing is critically important - Describe how to incorporate contract testing in your development practices - Show their team where they can get an introduction to the open source tool, Pact.
Recommended
More Related Content
Similar to Software contracts and microservices
Similar to Software contracts and microservices (20)
More from Seb Rose
More from Seb Rose (20)
Recently uploaded
Recently uploaded (20)
Software contracts and microservices
- 1. Software contracts - agility in the world of micro-services Seb Rose Mastodon: @sebrose@mastodon.scot Twitter: @sebrose Blog: https://cucumber.io/blog/ E-mail: seb.rose@smartbear.com Please help us by completing this 30 second microservices and contract testing questionnaire.
- 3. @sebrose h tt p:/ /smartbear.com Micro-service architecture … … a collec ti on of services that are: •Independently deployable •Loosely coupled •Organised around business capabili ti es •Owned by a small team •Highly maintainable and testable h tt ps:/ /microservices.io/
- 4. @sebrose h tt p:/ /smartbear.com Bene fi ts The micro-service architecture enables the rapid, frequent and reliable delivery of large, complex applica ti ons. It also enables an organiza ti on to evolve its technology stack. h tt ps:/ /microservices.io/
- 5. @sebrose h tt p:/ /smartbear.com Pi tf alls • The micro-service I depend on isn’t ready • The micro-service I depend on doesn’t provide the func ti onality I need • I’m not con fi dent that the new version of the micro-service will behave the same • We want to update our micro-service, but don’t know who is using it. Or how.
- 6. @sebrose h tt p:/ /smartbear.com You have a distributed monolith Beth Skurrie If you can’t deploy services independently, you don’t have micro-services. Spot the he ff alump
- 7. @sebrose h tt p:/ /smartbear.com TL;DR • All interac ti ons between so ft ware components are governed by contracts • Contract tes ti ng ensures that both components have the same expecta ti ons • Contract tests should be wri tt en by the developers
- 8. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 10. @sebrose h tt p:/ /smartbear.com Consumer & provider C P Contract
- 11. @sebrose h tt p:/ /smartbear.com Design by contract Design by contract Contract • an agreement between client and supplier Characteris ti cs • expect some bene fi ts • incur some obliga ti ons
- 15. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 16. @sebrose h tt p:/ /smartbear.com ▪Closed and complete Provider contracts express a service's business function capabilities in terms of the complete set of exportable elements available to consumers, and as such are closed and complete with respect to the functionality available to the system. ▪Singular and authoritative Provider contracts are singular and authoritative in their expression of the business functionality available to the system. ▪Bounded stability and immutability A provider contract is stable and immutable for a bounded period and/or locale. Provider contracts typically use some form of versioning to differentiate differently bounded instances of the contract. https://martinfowler.com/articles/consumerDrivenContracts.html Provider contracts
- 17. @sebrose h tt p:/ /smartbear.com ▪Open and incomplete Consumer contracts are open and incomplete with respect to the business functionality available to the system. They express a subset of the system's business function capabilities in terms of the consumer's expectations of the provider contract. ▪Multiple and non-authoritative Consumer contracts are multiple in proportion to the number of consumers of a service, and each is non- authoritative with regard to the total set of contractual obligations placed on the provider. Consumers may evolve at different rates. ▪Bounded stability and immutability Like provider contracts, consumer contracts are valid for a particular period of time and/or location. https://martinfowler.com/articles/consumerDrivenContracts.html Consumer driven contracts (CDC)
- 18. @sebrose h tt p:/ /smartbear.com How do you agree a contract?
- 19. @sebrose h tt p:/ /smartbear.com Provider team Consumer team How do you agree a contract?
- 20. @sebrose h tt p:/ /smartbear.com Provider team Consumer team How do you agree a contract?
- 21. @sebrose h tt p:/ /smartbear.com Provider team Consumer team How do you agree a contract?
- 22. @sebrose h tt p:/ /smartbear.com Provider team Consumer teams How do you agree a contract?
- 23. @sebrose h tt p:/ /smartbear.com You’re given it and have to live with it OR You nego ti ate and document a contract h tt ps:/ /microservices.io/ How do you agree a contract?
- 24. @sebrose h tt p:/ /smartbear.com • Each consumer captures their expecta ti ons of the provider in a separate contract. • All of these contracts are shared with the provider so they gain insight into the obliga ti ons they must ful fi l for each individual client. • The provider can create a test suite to validate these obliga ti ons. h tt ps:/ /thoughtworks.github.io/pacto/pa tt erns/cdc/ Consumer driven contracts
- 25. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 26. @sebrose h tt p:/ /smartbear.com C C Collaboration tests Monolithic approach Contract Collaboration Test Production P P
- 27. @sebrose h tt p:/ /smartbear.com C C Collaboration tests Test double Decoupled approach Contract Collaboration Test Production P
- 29. @sebrose h tt p:/ /smartbear.com C C Collaboration tests Test double Fail Collaboration Test Production Incorrect behaviour P
- 30. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 31. @sebrose h tt p:/ /smartbear.com JB Rainsberger, via GOOS mailing list, “Unit-test mock/stub assumptions rots” 15 March 2012 Systema ti c contract tes ti ng • Collabora ti on tests make assump ti ons about the contract • Contract tests try to jus ti fy those assump ti ons JB Rainsberger, via GOOS mailing list, “Unit-test mock/stub assumptions rots” 15 March 2012
- 33. @sebrose h tt p:/ /smartbear.com Test double I n t e r f a c e Hand-rolled contract tests Contract Test P
- 34. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 35. @sebrose h tt p:/ /smartbear.com CI Staging Prod C3 C2 C1 P3 P2 P1 CI - consumer & provider Test Test Test Test Test Test Test
- 36. @sebrose h tt p:/ /smartbear.com Agenda So ft ware contracts Where do contracts come from? Decoupling with test doubles Contract tests Managing dependencies Pact & Pact Broker Q & A
- 37. @sebrose h tt p:/ /smartbear.com Pact provides a mechanism for crea ti ng a contract between a service consumer and a service provider, and then providing the tools to validate that the consumer and provider adhere to the contact independently of each other. https://dius.com.au/2014/05/19/simplifying-micro-service-testing-with-pacts/ Simplifying consumer driven contracts
- 38. @sebrose h tt p:/ /smartbear.com •Consumer creates contracts using Pact DSL •When consumer tests are run: •Pact creates a mock HTTP server •a Pact fi le is created •Provider uses Pact fi le to verify compa ti bility •Provider may o ff er “backdoor” interface Pact - key points
- 42. @sebrose h tt p:/ /smartbear.com CI Staging Prod V32 V29 V27 Complica ti ons W3 W2 X9 X8 X7 Y15 Y14 Y9 Z84 Z73 Z72
- 43. @sebrose h tt p:/ /smartbear.com • Pacts are published by Consumer • Pacts are fetched by Provider • Results are stored in the “Matrix” • “Matrix” supports independent deployment Pact broker - key points
- 44. @sebrose h tt p:/ /smartbear.com Pact fl ow is the complete contract testing solution allowing teams to orchestrate and scale their contract testing initiative. Visibility to focus on what ma tt ers With Pact fl ow, developers can fi nd and fi x integration errors earlier in the SDLC and teams can improve communication & collaboration, reduce reliance on E2E tests resulting in faster and safer deployments.
- 45. @sebrose h tt p:/ /smartbear.com •Increases agility and con fi dence •Reduces need for integra ti on tests •Speeds up development •No subs ti tute for communica ti on •Is a development ac ti vity •Does not replace other forms of tes ti ng Take aways Contract tes ti ng:
- 46. https://bddbooks.com Please help us by completing this 30 second microservices and contract testing questionnaire. Seb Rose Mastodon: @sebrose@mastodon.scot Twitter: @sebrose Blog: https://cucumber.io/blog/ E-mail: seb.rose@smartbear.com Download these slides