This document discusses how to leverage asynchronous architectures like microservices to improve responsiveness and availability. It recommends redesigning business processes and user experiences to embrace some degree of asynchronicity. Workflow automation can help manage asynchronous processes and retries. If synchronous behavior is needed, a facade can be used to simulate it by waiting for asynchronous responses. But the facade should be prepared to handle failures and pushed to the edge to avoid latency creep.

1. Rethink Business Processes
and User Experience
to Leverage The Full Potential Of
Your Hipster Architecture
Bernd Ruecker
Co-Founder and Chief Technologist
@berndruecker

2. What‘s hipster?
Event-Driven
Reactive
Distributed Systems
Microservices
Agile
Streaming
Domain Driven Design
(DDD)
Cloud-Native
Eventual Consistency
JSON & YAML
Kubernetes
Serverless

3. What‘s not hipster?
Batch
Websphere
Monolithic Systems
Waterfall
Two-Phase Commit
Mainframe & Cobol
Serice oiented
architecture
SOAP & XML

4. Can you handle it?

5. Example
@berndruecker

6. Example
Payment
Seat
ReservationBooking
Ticket
Generation

7. Architecture
Payment
Seat
ReservationBooking
Ticket
Generation
Kafka
AMQP
REST

8. Example
@berndruecker
sync

9. That is hard to implement
Payment
Seat
ReservationBooking
Ticket
Generation
Kafka
AMQP
REST
REST

10. Workflow automation can help
Payment
Seat
ReservationBooking
Ticket
Generation
REST

11. Workflow automation can help
Payment
Seat
ReservationBooking
Ticket
Generation
REST
Workflow Automation:
Is stateful
Can wait
Can retry
Can escalate
Can compensate

12. But…

13. Weaknesses
Payment
Seat
ReservationBooking
Ticket
Generation
REST

14. Weaknesses: Latency creep
Payment
Seat
ReservationBooking
Ticket
Generation
REST
300 ms
1150 + x ms
600 ms
250 ms

15. https://developers.google.com/web/fundamentals/performance/why-performance-
mattersvhttps://developers.google.com/web/fundamentals/performance/why-performance-matters
• Pinterest increased traffic and sign-
ups by 15% when they reduced
perceived wait times by 40%.
• COOK increased conversions by 7%,
decreased bounce rates by 7%, and
increased pages per session by 10%
when they reduced average page
load time by 850 milliseconds.
• The BBC found they lost an
additional 10% of users for every
additional second their site took to
load.
• DoubleClick found 53% of mobile
site visits were abandoned if a page
took longer than 3 seconds to load.

16. Want to go serverless?
Payment
Seat
ReservationBooking
Ticket
Generation
REST
300 ms
1150 + x ms
600 ms
250 ms

17. Weaknesses: Availabiliy erosion
Payment
Seat
ReservationBooking
Ticket
Generation
REST
99 % uptime
99 % uptime
99 % uptime
96 % uptime

18. @berndruecker
https://www.reactivemanifesto.org/

19. And…

20. @berndruecker

21. Takes a while

22. Takes a while

23. Takes a while

24. Takes a while

26. HTTP
500
HTTP
200

27. Can your company
leverage your
hipster architecture?
Shutterstock
You need to
change business
processes and
customer
experience!

33. HTTP
202
HTTP
200

34. THIS!

35. @berndruecker
happy
case
failure
case
Redesign your business process accordingly!
Or some interface
to poll for status
Sync in happy case
Async response

37. @berndruecker
Redesign your business process accordingly!

38. Manifold reasons
drive change
https://developer.paypal.com/docs/checkout/
#how-the-buttons-work

40. Some degree of asynchronicity is
beneficial for your architecture!
@berndruecker

41. Example
Booking Payment
Retrieve
Payment
@berndruecker

42. Example
Booking Payment
Credit
Card
Retrieve
Payment
@berndruecker

43. Example
Booking Payment
Credit
Card
Retrieve
Payment
Rejected
@berndruecker

44. Example
Booking Payment
If the credit
card was
rejected, the
customer can
provide new
details
Credit
Card
Retrieve
Payment
Rejected
Rejected
@berndruecker

46. Example
Booking Payment
If the credit
card was
rejected, the
customer can
provide new
details
Credit
Card
Retrieve
Payment
Rejected
Rejected
@berndruecker

47. Example
Booking 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

48. Payment
failed
Who is responsible to deal with problems?
Booking Payment
If the credit
card was
rejected, the
customer can
provide new
details
Credit
Card
Retrieve
Payment
Rejected
Payment
received
@berndruecker

49. Payment
failed
Long running services
Booking Payment
Credit
Card
Retrieve
Payment
Rejected
Payment
received
Smart endpoints are
potentially long-running
@berndruecker
They need
persistent state
Ergo you need
Camunda :-)

50. Being able to implement
long running services
is essential for clear
responsibilities and better APIs
@berndruecker

51. Patterns
Fire & Forget Polling
Callback
Blocking Call

52. Patterns
Fire & Forget Polling
Callback
Blocking Call
HTTP 202
tricky
HTTP 202
HTTP 202
HTTP 200

54. Synchronous facade in front of asynchronous processing
Blocking Call

55. Example
Payment
Seat
ReservationBooking
Ticket
Generation
REST
Simulate synchronicty by waiting
(callback or polling)

56. Compare to e.g. AMQP
https://www.rabbitmq.com/tutorials/tutorial-six-java.html

57. Demo

58. Payment Example
Credit
Card
Payment
REST
REST

59. @Component
public class NotifySemaphorAdapter implements JavaDelegate {
public static Map<String, Semaphore> semaphors = new HashMap<>();
public void execute(DelegateExecution context) throws Exception {
Semaphore s = semaphors.get(context.getBusinessKey());
if (s!=null) {
s.release();
semaphors.remove(context.getBusinessKey());
}
}
public static Semaphore newSemaphore(String traceId) {
Semaphore sema = new Semaphore(0);
semaphors.put(traceId, sema);
return sema;
}
public static void removeSemaphore(String traceId) {
semaphors.remove(traceId);
}
}
@RequestMapping(path = "/payment/v4", method = PUT)
public String retrievePayment(String payload, HttpServletResponse response) {
String traceId = UUID.randomUUID().toString();
//...
Semaphore newSemaphore = NotifySemaphorAdapter.newSemaphore(traceId);
camunda.getRuntimeService().startProcessInstanceByKey("paymentV4", traceId, ...);
boolean finished = newSemaphore.tryAcquire(500, TimeUnit.MILLISECONDS);
NotifySemaphorAdapter.removeSemaphore(traceId);
if (finished) {
return "completed";
} else {
response.setStatus(HttpServletResponse.SC_ACCEPTED);
return "pending, traceId: " + traceId;
}
}

60. [HttpPut]
[Route("/api/payment/v4")]
public IActionResult RetrievePayment() {
var traceId = Guid.NewGuid().ToString();
//...
SemaphoreSlim semaphore = new SemaphoreSlim(1);
semaphore.Wait(); // aqcuire and release later
semaphors.Add(traceId, semaphore);
Camunda.BpmnWorkflowService.StartProcessInstance(
"paymentV4", new Dictionary<string, object> {
{"traceId", traceId }
});
ExternalTaskWorker semaphoreWorker =
startSempahoreWorker(traceId);
var success = semaphore.Wait(TimeSpan.FromMilliseconds(500));
semaphoreWorker.StopWork();
if (sucess) {
return Ok(result); // HTTP 200
} else {
semaphoreWorker.StopWork();
return Accepted(result); // HTTP 202
}
}
ExternalTaskWorker worker = new
CamundaClient.Worker.ExternalTaskWorker( //
Camunda.ExternalTaskService, //
new ExternalTaskWorkerInfo {
TopicName = "paymentResponseV4-" + traceId,
TaskAdapter = new NotifySemaphoreAdapter()
});
worker.StartWork();

61. Go hipster and use the cloud!

62. Push the facade towards the edge as far as possble
Payment
Seat
ReservationBooking
Ticket
Generation
REST

63. Summary
• To increase responsiveness and take responsibility in services
serious, you need some degree of asynchronicity
• Workflow automation can help you with a lot of challenges
around that
• If you need synchronous behavior, create a facade, but plan
for failure and push the facade to the edge

64. Thank you!
@berndruecker