The document discusses using an event-driven architecture for microservices integration. It defines what events and commands are, and explains how events allow microservices to communicate in real-time by consuming data before it is requested. The document outlines principles for a flexible, evolutionary and decoupled integration architecture using events. It provides examples of how business processes can be modeled with domain events that are published to a central event bus like Kafka to asynchronously integrate systems.

1. With events
to a modern
integration
architecture
How to use events in a modern microservice
world
Allianz in Germany |
Junker
Munich,
Berlin 19, 2022
©
Allianz
2022

2. • Principal Enterprise Architect at
Allianz in Germany
• Worked in different roles:
developer, product owner, architect
Publications
Lösungsmuster für
Cross-Cutting-Concerns in
Microservices, IT Aktuell, 06/2020
Microservices: Event-getriebene
Integrationsarchitekturen im Einsatz,
heise developer,.04/2022
Agile Unternehmensarchitekturen,
Java Magazin 12/2020
Blog:
https://annegretsarchitecture.blog/
Github: https://github.com/Grinseteddy
LinkedIn:
https://www.linkedin.com/in/dr-annegre
t-junker-141a99a4/
Twitter: Grinseteddy
About myself
2
© Wieland,
2020
INTEGRATION ARCHITECTURE

3. Event-Driven Architecture
Event-driven microservices allow for real-time
microservices communication, enabling data to be
consumed in the form of events before they’re
even requested.
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3
https://www.confluent.io/resources/event-driven-microservices/?utm_medium=sem&utm
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0v-fXs4y5uLX9L5YNgy94X2gu3-JkbBlXP37BnhhcRGQdWVNYZ62yRoCcqIQAvD_BwE,
5.4.2022
INTEGRATION ARCHITECTURE

4. 4
Event driven
architecture

5. What is an
event?
An event is something what already
happened. Usually we use “event” as
something which should happen – a
birthday, Christmas, … But technically
something happened e.g. a business
object reached a new status e.g. a task
became “Done”.
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2022
5

6. What is a
command?
If you use a command, then
something should happen, e.g. a
certain object should be created.
Commands can be transferred as
technical events. But when we
design a certain architecture we need
to differentiate in a clear way.
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7. Microservices Require Events
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EVENTS @ ALLIANZ
7
Self-Contained
Domain Service
Business
Service 1
Business
Service 2
Post
Response
Client
Post
Response
Post
Response

8. Microservices Require Events
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2022
EVENTS @ ALLIANZ
8
Self-Contain
ed Domain
Service
BO
Repository
Business
Service 1
BO
Repository
Business
Service 2
BO
Repository
Self-Contained
Domain Service
Business
Service 1
Business
Service 2
Post
Response
Client
Post
Response
Post
Response

9. Server2Server vs. Client2Server
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EVENTS @ ALLIANZ
9
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
Self-Contained
Domain Service
BO
Repository
West – East - Communication
Client
Domain MFE
Domain MFE
Domain MFE
Domain MFE
Domain MFE
Domain MFE
Domain MFE
Domain MFE
North-South-C
ommunication

10. ©
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Design
Principles
• Flexible architecture, which allows partners,
employees, and tied agents, to access the
different applications in different way so that
they can work according to their necessities
• Evolutionary architecture, which supports
step by step approaches and don’t require
big-bangs
• Flexible interface architecture, which allows
a standardized access, which includes legacy
interfaces
• Decoupling of applications via events, to
support an independent and fast
implementation by the according development
teams
• Integration of different backend
applications, to support a domain-driven
development

11. A Sample
for Events
11

12. Event-Driven Architecture
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The processing of architectural modules (micro services) is
controlled by events.
The scheduling diagram shows the event bus and producer
and consumer. Otherwise than a message broker, an event
broker stores events over a longer period. The event broker
does not send the events actively to the consumer. The
consumer reads the events at the event bus. So the
consumer does not need to be up and running, when an
event occurs.
INTEGRATION ARCHITECTURE

13. How to get an event
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Subjective user view on a business
process and visual glossary for definition
of terms
Collecting of business events along the
process, assigning of aggregates (business
objects), roles, technical processes, views
to the events, definition of domains, and
necessary APIs
Formulating of the API as Swagger file
(OpenAPI 3.0 standard) – contract between
partner and Allianz
A Domain Story Telling B Event Storming C
JSON Object/
Swagger File /
Business Description
Procedural
Step
Descrip
tion

14. Onboarding Process of a Customer
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Allianz Customer Model - ACM
Lead Generation
and Management
Relationship
Building
Quotation
Offer and
Follow-up
▪ Generation of Leads and their
qualification
▪ Start of the real sales
opportunity process
▪ Parametrization and calculation
of the quotes
▪ Offer is presented for
signature
▪ Customer is bidden for
feedback
▪ Follow-ups are arranged
Sales Opportunity
▪ Get in contact with the prospect
▪ Collect of the prospect data
▪ Invitation of the prospect to the
advisory meeting
▪ Introduction of the agent and risk
assessment of the prospect
INTEGRATION ARCHITECTURE

15. 15
Quote
Product x
Enter
Parameters
Calculate
Tariff
Assess Risk
Calculate
Tariff
Offer with
Variants
Quotation
Underwriter
Workplace
Task Mngmt
Hand over
Documents
Create
Customer
Documents
Select
Quotes
Feedback
Session
Arrange
next Steps
Contract Creation
Create
Applications
Accept Risk
Create
Contract
Quotes
Document
Services
Advisor
y
Lead
Management
Qualify Lead
Automatically
Create Lead
Qualify Lead
Manually
Customer
Management
Check / Enhance Data
g
Quotation
Parameters
Risk Assessment
Automatically
Quotation Automatically
Offer Creation
Underwriter
Workplace
Manual Risk
Assessment
Manual Quotation
Advisory
Life Situation
Introduce Agency
Risk Assessment
Product Selection
Feedback Session
Task
Management
Contact Prospect
Arrange Appointment
Arrange next Steps
Document
Services
Create Documents
Hand over Documents
Select and Sign
Documents
Policy
Management
Automatic Application
Creation
Automatic Risk
Assessment
Automatic Contract
Creation
Policy Mnmgt
Task Mngmt Task Mngmt
Cust.
Mngmt
Advisor
y
Contact
Prospect
Check &
Enhance
Data
Arrange
Appointm.
Life
Situation
Introduce
Agency
Risk
Assessment
Product
Selection
Lead Mngmt
Create
Lead
Qualify
Lead
Qualify
Lead
New New Legacy New Legacy New Legacy Legacy Legacy
INTEGRATION ARCHITECTURE

16. Domain Model
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Opportunity
Process
Lead Task Customer Advisory Quote Risk Document Contract
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
Process ID as Foreign
Key
1 1 1..* 1 1 1 1 1
✔ Flexible architecture
✘ Evolutionary architecture
✘ Flexible interface architecture
✔ Decoupling of application via events
✘ Integration of different backend applications including legacy applications
INTEGRATION ARCHITECTURE

17. Synchronous Approach
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Lead
Management
Customer
Management
Quotation
Advisory
Task
Management
Document
Services
Policy
Management
Sales Portal
Sales Process
Management
INTEGRATION ARCHITECTURE
Layer
Layer
Layer

18. Domain Model
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Opportunity
Process
Lead Task Customer Advisory Quote Risk Document Contract
Lead Event
Task Event
1 1 1..* 1 1 1 1 1
✔ Flexible architecture
✔ Evolutionary architecture
✔ Flexible interface architecture
✔ Decoupling of application via events
✔ Integration of different backend applications including legacy applications
INTEGRATION ARCHITECTURE
Customer
Event
Advisory
Event
Quote Event
Risk Event
Document
Event
Contract
Event

19. Asynchronous Approach
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2022
INTEGRATION ARCHITECTURE
19
Lead
Management
Customer
Management
Quotation and
Underwriter
Advisory
Task
Management
Document
Services
Policy
Management
Sales Portal
Sales Process
Management
Kafka
Layer
Layer Layer
Layer Layer

20. ©
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2022
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21. Events on Kafka as Topics
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INTEGRATION ARCHITECTURE

22. Take
aways
22

23. Take Away
Decoupled
Systems are
easier to
understand
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With event-driven systems, we can decouple
systems and better understand our software.
INTEGRATION ARCHITECTURE

24. Take Away
Integration of
legacy systems
are simply
easier with an
event-driven
approach.
©
Allianz
2022
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With event-driven systems, we can decouple
systems and better understand our software.
INTEGRATION ARCHITECTURE

25. ©
Allianz
2022
Vielen Dank!
annegret.junker@allianz.de