Talk held on 21st of Septemer 2017 at Bedcon Java conference in Berlin about the 7 sins of workflow management in Java

1. The 7 sins of workflow
mail@bernd-ruecker.com

2. The 7 sins of workflow
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3. What is workflow?

4. The obvious use case
for workflow:
Human task management

5. A simple example
Human task
management
Service
collaboration
Events , e.g.
timers
* Modeled in BPMN
= ISO Standard for modeling and execution

6. Tasklists and task forms
…

7. Another use case:
service collaboration

8. Service A
Challenge: Synchronous collaboration
Call
service B
Service B
The network is unreliable
Hystrix adds circuit
breaker & fail fast
Retry capability & async
behavior is missing

9. Service A
Challenge: Asynchronous collaboration
Send
message
to B
Service B
Wait for
response
Timeout handling
Message correlation &
deduplication
State handling
Parallelism & merging

10. Challenge: Distributed transactions
1. book
hotel
2. book
car
3. book
flight
6.
cancel
hotel
5.
cancel
car
4. In case of
failure trigger
compensations
book
trip
Service A
Car ServiceHotel Service Flight Service
ACID-Transactions
only local in the
service contexts
Distributed
transaction via Saga
pattern using
compensating
activities

11. A workflow engine is a (persistent) state machine

12. What BPMN can do

13. What BPMN can do

14. What BPMN can do

15. Toolbox for distributed systems
Handling of time &
timeouts
Retry
Versioning
Compensation & Saga
Message correlation &
deduplication

16. Decisions

17. Workflow
and BPM

19. … and death by
properties panel
Same story with BPM:
Shiny vendors promised zero-code …
proprietary, alien
like tools …

20. Let‘s simply build
this ourselves…*
* how hard can it be…

21. It is en-vogue

22. This is not a new idea…
Own DSL, parsing, graphical representation,
modeler, persistence, escalation, version
management, tooling, …

23. Alarming by
management attention

27. The 7 sins of workflow
Zero-code suites
Homegrown
engine
No engine Wrong engine
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28. BPM done right
Developer friendly Composable BizDevOps

29. …
There are lightweight and open source
workflow engines or state machines
available. Leverage them!

32. Spring Boot example
@Component
@EnableBinding(Sink.class)
public class MessageListener {
@Autowired
private ProcessEngine camunda;
@StreamListener(target = Sink.INPUT)
public void orderPlacedReceived(Message<Order> message) {
camunda.getRuntimeService().createMessageCorrelation(message.getMessageType())
.processInstanceBusinessKey(message.getTraceId())
.setVariable("orderId", message.getPayload())
.correlate();
}
}

33. Living documentation

34. Executable specifications

35. Operational visibility
345 67812

36. The 7 sins of workflow
Zero-code suites
Homegrown
engine
No engine Wrong engine
4
6
5
7

37. The 7 sins of workflow
Zero-code suites
Homegrown
engine
No engine Wrong engine
4
6
5
Stakeholders
habitat violation

38. The 7 sins of workflow
Zero-code suites
Homegrown
engine
No engine Wrong engine
6
5
Granularity
bloopers
Stakeholders
habitat violation

39. Example

40. The 7 sins of workflow
Zero-code suites
Homegrown
engine
Granularity
bloopers
Over engineering
No engine Wrong engine Wrong usage
6
Stakeholders
habitat violation

41. The 7 sins of workflow
Zero-code suites
Homegrown
engine
Granularity
bloopers
BPM monolith
Over engineering
No engine Wrong engine Wrong usage
Stakeholders
habitat violation

42. Microservice Orchestration?

43. End-to-end processes cross microservice boundaries
Order
Inventory
Payment

44. Payment
Distributed flows are owned by microservices
Order
Distributed
orchestration

45. End-to-end processes as 1st class citizen
PaymentOrder
Core
Capability
Support
Capabilities
Business
Capabilities

46. Order
Order
Order
Order
Architecture
Order
Engine A
Payment
Engine B
Monitoring
Human Task
Management
Coarse grained
central
monitoring
Fine grained
monitoring &
operations
(per context)
DevOps
Tec
Ops Biz
Ops
Central

47. Example
InventoryPaymentOrder ShippingCheckout Monitor
https://github.com/flowing/flowing-retail/

48. Container
(e.g. Tomcat, WildFly, Websphere, …)
Architecture possibilities
Your application
Engine
DB
BPMN Java …
Your application
Engine
DB
BPMN Java …
Engine
(Docker,
Tomcat, …)
Your application
DB
Embedded engine Container managed engine Remote engine
BPMN
Java, C#,
Go, JS, …

49. Live

50. New kid on the block
https://zeebe.io/
Zeebe
Broker
Your
application
Binary (MsgPack)
Support streaming & batching
Client
Horiziontally
scalable
Append only log / event sourcing

51. Summary: How to avoid the 7 sins?
• Use a lightweight workflow engine or
state machine
• Use it properly – as a state machine
(state, timeouts, retrying, message
correlation & deduplication,
compensation)
• Do not model everything
• Leverage BizDevOps & embrace visibility
• Slice your processes fitting your contexts
(monolith vs. microservices)
• Avoid over-engineering (enterprise-wide
xyz, abstractions, …)

52. Avoid the 7 sins and life will be great!

53. Thank you!

54. Code:
https://github.com/berndruecker
Slides:
https://bernd-ruecker.com
Blog:
https://blog.bernd-ruecker.com
Feedback:
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