Slides from my talk at the Camunda DACH Roadshow in January of 2019 about how to apply workflow automation when doing microservices

1. @berndruecker
Workflow Automation in
Microservice Architectures

2. What? Why?
Microservices & Workflow Automation
How?
t

3. What? Why?
Microservices & Workflow Automation
How?
t

4. Microservices…
Service
B
Some
Service
Some
Service Some
Service
Service
C
Service
A
Service
D
Monolith
Functionality
A
Functionality
B
Functionality
C
Functionality
D

5. Photo by born1945, available under Creative Commons BY 2.0 license.

6. What we wanted
Photo by Lijian Zhang, available under Creative Commons SA 2.0 License and Pedobear19 / CC BY-SA 4.0

7. https://blog.bernd-ruecker.com/the-microservice-workflow-automation-cheat-sheet-fc0a80dc25aa

8. Example: http://github.com/berndruecker/flowing-retail
Checkout
Payment
Inventory
Shipment
?

9. Order
Checkout
Payment
Inventory
Shipment
An „orchestration process“?

10. Every workflow must be
owned by one microservice.
No exceptions!

11. Order
Checkout
Payment
Inventory
Shipment

12. Otherwise you end up with SOA again!
Checkout
Payment
Inventory
Shipment
Order

13. No BPM(N) monoliths
https://blog.bernd-ruecker.com/avoiding-the-bpm-monolith-when-using-bounded-contexts-d86be6308d8

14. Workflows live inside service boundaries

15. Order
Placed
Payment
Received
Goods
Fetched
Notification
Order
Checkout
Payment
Inventory
Shipment
Event-driven architecture

16. Peer-to-peer event chains
Checkout
Payment
Inventory
Shipment
Order
placed
Payment
received
Goods
shipped
Goods
fetched

17. Peer-to-peer event chains
Checkout
Payment
Inventory
Shipment
Order
placed
Payment
received
Goods
shipped
Goods
fetched

18. 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

19. 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

20. 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

21. Finding the right balance
31
Observe Microservice Paradigms
● Loose Coupling
● Autonomy
● Event Collaboration
Ensure Flow Manageability
• End-To-End Visibility
• Meet Business Process SLA
• Support Continuous Process
Improvement

22. Tracking
Checkout Inventory
Payment Shipment
Event Bus
Workflow
Engine
https://www.confluent.io/kafka-summit-sf18/the_big_picture

23. Tracking + BI
Checkout Inventory
Payment Shipment
Event Bus
Workflow
Engine
Camunda
Optimize
Other reporting
/ BIO solutions

24. But you can start acting upon certain events

25. Order
Checkout
Payment
Inventory
Shipment
Orchestration

26. Orchestration makes it easy to change the flow

27. Peer-to-peer event chains
Checkout
Payment
Inventory
Shipment
Order
placed
Payment
received
Goods
shipped
Goods
fetched
Fetch the goods
before the
payment

28. Peer-to-peer event chains
Checkout
Payment
Inventory
Shipment
Fetch the goods
before the
payment
Goods
fetched
Order
placed
Payment
received
Goods
shipped

29. Order
Commands vs. Events
Checkout
Payment
Inventory
Shipment
Order
placed
Retrieve
payment

30. Order
It is about where to decide about the coupling!
Checkout
Payment
Inventory
Shipment
Order
placed
Retrieve
payment
Order decides
. to listen to the event
. to issue the command

31. Microservices =
Distributed systems

32. Order
Checkout
Payment
Inventory
Shipment
Stateful orchestration
This orchestration
requires state

33. Order
Checkout
Payment
Inventory
Shipment
Orchestration
Orchestration is independant of
communication channel!
This might be REST, Messaging,
Event-Bus, …

34. Workflow Engine
Typical ways of communication
Checkout
Payment
Order
Shipment Checkout
Payment
Order
Shipment
Checkout
PaymentOrder
Shipment
Message/Event Bus REST-ish

35. Workflow Engine
Typical ways of communication
Checkout
Payment
Order
Shipment Checkout
Payment
Order
Shipment
Checkout
PaymentOrder
Shipment
Message/Event Bus REST-ish
Pub/SubOwnership

36. Checkout
Payment
Order
Shipment
Workflow
Engine
Workflow
Engine
Monitoring
Checkout
Payment
Order
Shipment
Workflow
Engine
Monitoring
How many workflow engines?

37. Monitoring
Checkout Inventory
Payment Shipment
Workflow
Engine
Order
Workflow
Engine
Monitor
e.g.
Elastic
Links back
Optimize

38. Example
https://github.com/berndruecker/flowing-retail/tree/master/kafka/java/monitor

39. Recap
• Microservices have its merits
• You need to balance orchestration and chorography
• Track, monitor or manage the flow – depending on your scenario
• Distributed systems need stateful orchestration
• Visibility is essential to survive
• Workflow automation is an essential building block,
make sure to use BPMN

40. Microservices & Workflow Automation
http://berndruecker.io/

41. Thank you!

42. mail@berndruecker.io
@berndruecker
https://berndruecker.io
https://medium.com/berndruecker
https://github.com/berndruecker
https://www.infoq.com/articles/events-
workflow-automation
Contact:
Slides:
Blog:
Code:
https://www.infoworld.com/article/3254777/
application-development/
3-common-pitfalls-of-microservices-
integrationand-how-to-avoid-them.html
https://thenewstack.io/5-workflow-automation-
use-cases-you-might-not-have-considered/