10 tips to integrate different applications putting more focus into asynchronous communications using Domain Events.

1. INTEGRATING BC
PHP DUTCH 2016 #DPC16

2. @BUENOSVINOS
/GOODWINES/

4. TEXT

5. REAL EXAMPLES WRITTEN IN PHP
SHOWCASING DDD ARCHITECTURAL
STYLES, TACTICAL DESIGN, AND BOUNDED
CONTEXT INTEGRATION
foreword by Matthias Noback
https://leanpub.com/ddd-in-php

6. START

7. E-COMMERCE
FRAUD
GAMIFICATION

8. SYNC / ASYNC
REST / MESSAGING

9. TIPS
WHEN DEALING WITH DOMAIN EVENTS

10. DDD ARCHITECTURAL STYLES TRIP
SPAGUETTI
FRAMEWORK
HEXAGONAL
HEXAGONAL + CQRS
CQRS + ES

11. START FIRING
DOMAIN EVENTS NOW
TIP #1

12. DOMAIN EVENTS ARE THING THAT
HAPPEN IN OUR DOMAIN THAT DOMAIN
EXPERTS CARE ABOUT
Vaughn Vernon
DEFINITION

13. DOMAIN EVENT INTERFACE

14. LOG IN ATTEMPTED DOMAIN EVENT

15. PUBLISHING DOMAIN EVENTS

16. OUR DOMAIN EVENT PUBLISHER

17. DO SOMETHING SIMPLE
WITH THE EVENTS
TIP #2

18. DOMAIN EVENT SUBSCRIBER INTERFACE

19. LOG DOMAIN EVENTS INTO ELASTICSEARCH WITH MONOLOG

20. REGISTER YOUR NEW LISTENER/SUBSCRIBER

23. PERSIST ALL YOUR
DOMAIN EVENTS IN
YOUR MAIN STORAGE
(DB)
TIP #3

24. …WHEN A NEW APPLICATION ARRIVES
YOU CAN REPLAY ALL THOSE EVENTS AGAINST THE
NEW APPLICATION TO LOADED WITH ALL THE INFO…

25. SUBSCRIBER TO PERSIST ALL DOMAIN EVENTS

26. LISTENER TO PERSIST ALL DOMAIN EVENTS

27. EVENT STORE BASED IN DOCTRINE

28. EVENTS IN THE DATABASE

29. PERSIST
DOMAIN EVENTS
IN THE SAME TX AS
DOMAIN CHANGES
TIP #4

30. A USER CHANGES HIS EMAIL
EMAILWASUPDATED

31. POSSIBLE SCENARIOS
Not notifying about something that
happened :(
Notifying about something that do NOT
happened :((

32. CHANGES TO YOUR DOMAIN AND DOMAIN
EVENTS SUCCESS OR FAIL AT THE SAME TIME
TOGETHER

33. PROVIDE A REST API
FOR YOUR DOMAIN
EVENTS
TIP #5

34. …IF IT LOOSES A DOMAIN EVENT
ANOTHER APP CAN SYNC ITS STATUS WITH YOUR
EVENTS API

35. API EVENTS ENDPOINT

36. API EVENTS ENDPOINT RESULT

37. KEEP TRACK OF
LAST PUBLISHED
DOMAIN EVENT
TIP #6

38. PUBLISHING EVENTS

39. SPREADING EVENTS

40. EVENT STORE AND MESSAGE TRACKER

45. USE SUPERVISORD TO
CONSUME BATCH OF
LIMITED DOMAIN
EVENTS
TIP #7

46. CONSUMING DOMAIN EVENTS

47. TEXT

48. USE SUPERVISOR TO FIRE WORKERS AND KEEP THEM RUNNING

49. USE SUPERVISOR TO FIRE WORKERS AND KEEP THEM RUNNING

50. USE TACTICIAN OR
OTHER COMMAND
BUSES
TIP #8

51. FROM MESSAGE TO AN COMMAND HANDLER

52. IF USING SYMFONY PHP-AMQPLIB/RABBITMQ-BUNDLE AND LEAGUE/TACTICIAN-BUNDLE

53. PROTECT YOURSELF
FROM DUPLICATE
MESSAGES WITH
IDEMPOTENCE
TIP #9

54. TEXT

55. TREAT YOUR
DOMAIN EVENTS AS
YOUR REST API
TIP #10

56. DOCUMENT YOUR DOMAIN EVENTS AS YOU WOULD DO WITH YOUR REST API

57. USE SAMI, FOR EXAMPLE

58. VERSION YOUR DOMAIN EVENTS

59. WRAP-UP

60. WRAP-UP
INTEGRATING BOUNDED CONTEXT TIPS
▸ Integration strategies: Messaging (Async) over REST (Sync)
▸ Start firing Domain Events from deeper in your Model as possible
▸ Add simple listeners in your bootstrapping (Elastic + Kibana)
▸ Persist Domain Events into your main storage in the same Tx as Domain changes
▸ Provide an API endpoint for your Domain Events so other apps can get in sync
▸ Publish your Domain events to a Messaging System (RabbitMQ) and keep track of the last
messages sent
▸ Protect yourself with Idem Potent operations

61. THANKS!
@BUENOSVINOS
HTTPS://JOIND.IN/TALK/612BA