Transactions in micro-services (fall 2019)
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The document discusses the implementation of transactions in microservices architecture, specifically focusing on long running actions (LRA) using MicroProfile. Key concepts include ACID properties, the saga pattern, and how to manage multiple data sources effectively. It provides code examples and resources for utilizing MicroProfile LRA in Java EE environments.
Transactions in micro-services (fall 2019)
- 1. #javazone Transactions in your micro- services architecture Dawn Parzych (CatchPoint)
- 2. #javazone What ? • Transaction and Micro-Services • MicroProfile LRA (Long Running Actions) • Demo
- 3. Rudy De Busscher • Payara • Service team • Involved in • Committer of MicroProfile • Committer in Eclipse EE4J groups • Java EE Security API Expert group member @rdebusscher https://blog.payara.fish/ https://www.atbash.be
- 4. #javazone Transaction • Typical concept from the ‘Monolith’ • Start - End • Typical short - to avoid locks • Multiple datasources supported with XA transactions
- 5. #javazone Transaction • Distributed - XA transactions • 2 Phase Commit • Not scalable • Locks DZone - XA transactions fizalihsan - Transactions
- 6. #javazone To be ACID or Not • Atomicity: All or Nothing • Consistency: All values are aligned • Isolation: Different transactions can’t see ‘temporal’ values • Durable: Reliably Stored • CAP Theorem • Consistency - Availability - Partitioning
- 7. #javazone Long Running Transactions • Multiple Datasource • Several steps over long period • Single Unit of Work? Web Services Journal
- 8. #javazone Example • Book Flight • Book Hotel • Payment AltexSoft
- 9. #javazone MicroService world • No Atomicity • Eventual Consistency • No Isolation • Durable KumuluzEE
- 11. #javazone • Optimizing Enterprise Java for a Micro-services Architecture • Based on some Java EE (Jakarta EE) specs
- 12. #javazone • First release candidate available • API more or less stable MP Long Running Action
- 13. #javazone MicroProfile LRA • Long Running Actions • Features • Loose coupling • Guaranteed a globally consistent outcome • Compensatable actions (SAGAs)
- 14. #javazone LRA Components JAX-RS resource JAX-RS resource JAX-RS resource Coordinator Participant Participant Participant Callback Enlist
- 15. Demo
- 16. #javazone Some Key code concepts • @LRA • LRA Level / defines transaction • @Compensate • Participant level: Not present, not a participant. • @Complete • Participant level • LRA ID ( = URI) • Uniquely defines the Long Running Action (transaction) • Propagated through Header
- 17. #javazone LRA Types • Required for each JAX-RS resource Active LRA No LRA Required Use Active Start New Requires New Start New Start New Mandatory Use Active Error Supports Propagate - Never Error - Not Supported Not propagated - Participant Not listed: type Nested
- 18. Demo Service A Service B Service C Start End Distributed
- 19. #javazone Returning Participant Status • Immediate • Return type ParticipantStatus, void • Asynchronous return • Return CompletableFuture<ParticipantStatus> • Idempotent @Complete/@Compensate • Return type ParticipantStatus • ParticipantStatus.Completing / ParticipantStatus.Compensating • Through @Status method • First call to @Complete/@Compensate • Following calls to @Status
- 20. #javazone TimeOut • By Default, LRA runs forever • But also by Default, immediately closed • Closed explicitly (end=true) • Define a timeout -> cancelled / all participants compensated.
- 21. #javazone Remove Participant • @Leave • Remove Participant from LRA • Developer responsible for cleanup • No @Compensate/@Complete/@Status called
- 22. #javazone Feedback final status • @AfterLRA • What was the final outcome • For participants • For ‘parties’ • Can be used for any @LRA, not @Compensate annotated class.
- 23. #javazone Store LRA Info • LRA only performs orchestration • Participant needs to keep track of LRA • Store LRA Id as part of your business data • Extension • LRAData • ParticipantData
- 24. #javazone Takeaways • Classic approach for Transactions and Long Running Action not applicable for micro-services • MicroProfile LRA uses Compensatable actions • Loosely coupled on top of JAX-RS resources • Specification : In progress
- 25. #javazone Code • Project https://github.com/eclipse/microprofile-lra • Demo code • https://github.com/rdebusscher/mp-lra-demo
- 26. #javazone Thank You Not using the Payara Platform yet? Download the open source software: Payara Server or Payara Micro https://payara.fish/downloads Need support for the Payara Platform? https://payara.fish/support