JCon Live 2023 - Lice coding some integration problems
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The document discusses integration patterns for microservices, emphasizing the importance of resilience and stateful retries in managing failures during processes like check-in and payment. It highlights the complexities introduced by distributed systems and the necessity of designing robust service boundaries to enhance customer experiences. The author advocates for leveraging event-driven architectures while being cautious of losing sight of larger-scale flows.
JCon Live 2023 - Lice coding some integration problems
- 2. Photo by Tookapic, available under Creative Commons CC0 1.0 license.
- 3. „There was an error while sending your boarding pass“
- 7. Some Service Some Service Some Service Some Service Some Service Some Service Some Service Failure will happen. Accept it! But keep it local! Be resilient.
- 10. Check-in Barcode Generator Web-UI Me Output Mgmt Current situation – the bad part Stateful Retry
- 12. We are having some technical difficulties and cannot present you your boarding pass right away. But we do actively retry ourselves, so lean back, relax and we will send it on time.
- 14. Check-in Barcode Generator Web-UI Me Output Mgmt Possible situation – much better! Stateful Retry
- 15. Check-in Barcode Generator Web-UI Me Output Mgmt Stateful Retry Possible situation – much better! The failure never leaves this scope!
- 16. Resulting challenges Persistent state Asynchronous communication We will talk about why this is a good thing in a minute! Solve technical challenges (operating, scheduling, versioning, visibility, scalability, …) without accidential complexity Change the user experience
- 18. bernd.ruecker@camunda.com @berndruecker http://berndruecker.io/ Bernd Ruecker Co-founder and Chief Technologist of Camunda
- 19. Check-In A workflow engine is a durable state machine Barcode REST Stateful retry
- 20. „The customer wants a synchronous response“ Check-in Barcode Generator Web-UI Me Output Mgmt „Eh – no!“
- 21. Simple example for live coding Credit Card Payment REST
- 23. Payment Now you have a state machine! Credit Card REST
- 24. Do you have to program all integration logic? 26
- 26. @berndruecker
- 27. Connectors Modeling Experience Low-code Forms Human Task Orchestration CAMUNDA Low-code Pro-code Process Orchestration Kopfhörer
- 28. @berndruecker
- 29. @OutboundConnector( type = "io.camunda:http-json:1", inputVariables = {"method", ...}, ) public class HttpJsonFunction implements OutboundConnectorFunction { public Object execute(final OutboundConnectorContext context) throws Exception { final var json =; final var request = createRequest(context); return httpService.executeConnectorRequest(request); } } { "name": "REST Connector", "properties": [ { "type": "Hidden", "value": "io.camunda:http-json:1", "binding": { "type": "zeebe:taskDefinition:type" } }, { "id": "method", "label": "REST Method", "group": "endpoint", "type": "Dropdown", "value": "get", "choices": [ https://github.com/camunda/connectors-bundle/tree/main/connectors/http-json
- 30. @berndruecker
- 31. Runs anywhere Multiple connector runtime options, including SaaS, self-managed, co- located, and local installations @berndruecker
- 38. Payment But back to integration logic… Credit Card REST
- 39. has to implement Retry has to implement Idempotency Client Service Provider
- 40. Make every service idempotent! Credit Card Payment Charge Credit Card cardNumber amount Charge Credit Card cardNumber amount transactionId Not idempotent Idempotent charge
- 43. Don‘t worry, it will happen safely – even if you loose connection. Feel free to reload this page any time!
- 44. Distributed systems introduce complexity you have to tackle! Credit Card Payment REST
- 46. It is impossible to differentiate certain failure scenarios. Independant of communication style! Service Provider Client
- 47. Distributed systems introduce complexity you have to tackle! Credit Card Payment REST
- 48. Distributed systems introduce complexity you have to tackle! Credit Card Payment REST Cancel charge
- 49. retrievePayment HTTP 200 OK HTTP 202 ACCEPTED Payment Happy case: Synchronous response Otherwise: asynchronous Embrace asynchronicity
- 51. Long running capabilities are essential to design good service boundaries (= a good architecture) @berndruecker
- 55. Example Order Fulfillment Payment If the credit card was rejected, the customer can provide new details Credit Card Retrieve Payment Rejected Rejected @berndruecker
- 56. Example Order Fulfillment Payment If the credit card was rejected, the customer can provide new details Credit Card Retrieve Payment Rejected Rejected @berndruecker A few smart god services tell anemic CRUD services what to do Sam Newmann
- 57. Payment failed Who is responsible to deal with problems? Order Fulfillment Payment If the credit card was rejected, the customer can provide new details Credit Card Retrieve Payment Rejected Payment received @berndruecker
- 58. Payment failed (Potentially) long running services Order Fulfillment Payment Credit Card Retrieve Payment Rejected Payment received @berndruecker
- 59. Long running capabilities are essential to design good service boundaries (= a good architecture) @berndruecker
- 60. You need to redesign your customer journeys to leverage your hipster architecture! Shutterstock
- 61. Did you just say “hipster”?
- 62. Let‘s talk about messaging.
- 63. Who uses a message bus?
- 64. Who has no problems operating a message bus? Dead messages | No context | Inaccesible payload | Hard to redeliver | Home-grown message hospitals | …
- 65. Using messaging Credit Card Request Dead letter queue (DLQ)
- 66. Using messaging Credit Card Request Dead letter queue (DLQ)
- 70. Did you just say “hipster”?
- 74. Phil Calcado at QCon NYC 2019
- 75. Notification Checkout Payment Inventory Shipment @berndruecker Pinball Machine Architecture „What the hell just happened?“ @berndruecker
- 76. What we wanted Photo by Lijian Zhang, available under Creative Commons SA 2.0 License and Pedobear19 / CC BY-SA 4.0
- 77. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 78. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 79. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 81. Orchestration logic live inside service boundaries
- 82. Event-driven example Inventory Payment Order Shipping Checkout Monitor https://github.com/berndruecker/flowing-retail/ Human Tasks H2 H2
- 84. Summary
- 85. Thank you!