Master the flow of microservices - because your business is more complex than ...
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@berndruecker #VoxxedVienna Because your business is more complex than * * Some big video streaming company [email protected] With thoughts from http:// flowing.io @berndruecker | @martinschimak
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Transcript of Master the flow of microservices - because your business is more complex than ...
@berndruecker#VoxxedVienna
Because your business ismore complex than *
* Some big video streaming company
With thoughts from http://flowing.io@berndruecker | @martinschimak
FAMGA
FANG
Tech stack
https://www.slideshare.net/RaminForood/platform-data-technologies-at-netflix
Noorchestration.
Orchestration
Netflix recognized challenges in orchestration
Let‘s do some groundwork before wedive into orchestration…
System complexity increases dramatically
Warehouse System
LogisticsPlatform
TaxiSystem
TravelPlatform
Insurance System
Insurance Platform
Heating with temperature
sensor
Smart Heating(Cloud
controlled)
…
…
Helpful paradigms
Microservices Event Driven & Reactive Domain Driven Design
Microservices
• Independent components
• Independent deployments
• Decoupling between components
• Dedicated teams to fight conways law
• Autonomy of technology decisions
• Avoid horizontal team boundaries
• New DevOps paradigms
Microservice
Microservice
Microservice
Monolith
A
B
C
A
B
C
Event driven microservices
Microservice Microservice Microservice
A B C
Eventbus
Communication via events
Microservice Microservice
A C
Eventbus
Event
event namepayload
no receipient
Communication via Events
Microservice Microservice
A C
Eventbus
Event
Does not know
about C
Does not know
about A
Compare to SOA
Service Service
A C
ESB
„smart endpoints and dumb pipes”
Value proposition: fight conway, keep agility and ease changes
Microservice Microservice
A C
Eventbus
Yeah.
Example: Simple order handling
pay receive
shipment
place
order
I want to buy this!
I am happy!
Sample Microservices
Inventory Service
Handles Stock, Reserviations andphysical handlingof goods
Payment Service Handles Payment
Shipping Service
Manage shipments & labels for logisticproviders
Eventflow
Order Placed
Payment Received
GoodsPicked
GoodsShipped
InventoryPayment ShippingShop
Implementation
Let‘s zoom in the payment service
Payment Serviceorderplaced
paymentreceived
Let‘s zoom in the payment service
Payment Serviceorderplaced
paymentreceived
The payment servicehas to listen to
„order placed“ event
De-coupling?
Payment Service
orderplaced
servicefullfilled
…
Whenever a new service requirespayment, the payment has to bechanged
Payment has to know all possibleevents that trigger a payment
subscriptionconfirmed
Martin Fowler also recognized
Event notification is nice because it implies a low level of coupling, and is pretty simple to set up. It can become problematic, however, if there really is a logical flow that runs over various event notifications. The problem is that it can be hard to see such a flow as it's not explicit in any program text. Often the only way to figure out this flow is from monitoring a live system. This can make it hard to debug and modify such a flow. 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
Event Command Transformation
Payment Servicedo
paymentorderplaced Transformation
CommandSomething has to happenin the future1 recipient
EventSomething has happendin the past0..n recipients
This calls for an order service
Payment servicedo
paymentorderplaced Order service
Microservices
Inventory service
Payment service
Order service
Does eventcommandtransformationfor orders
Shipping service
Event Command Transformation
dopayment
orderplaced
OrderService
paymentreceived
pickgoods
goodspicked
shipgoods
goodsshipped
orderdelivered
OrderService
OrderService
OrderService
Smeels like a central ESB?
http://apsblog.burtongroup.com/2009/01/soa-is-dead-long-live-services.html
No! Far from it!
Inventory service
Payment service
Order serviceMight beimplemented in simple Java
Shipping service
Order service does the orchestration
Implementation (with event command transformation)
Some things in life are slow
dopayment
orderplaced
paymentreceived
pickgoods
goodspicked
shipgoods
goodsshipped
orderdelivered
OrderService
Long Running
Long Running
Long Running
Long Running
You also have to handle state.
Bernd Rücker
Co-founder Camunda> 10+ years workflow
http://bernd-ruecker.com/[email protected]
Camunda
Open source vendorBerlin + San Francisco
> 60 employeesNo venture capital
www.camunda.org
The 7 sins of workflow and Java
Homegrownengine
No engine Wrong engine
4
6
5
7
All sins: http://blog.bernd-ruecker.com/
Zero-code suites
Wrong usage
ToolsState Visibility
[ Orchestration | Workflow | BPM ] Engine
Order example in BPMN*
*BPMN = ISO standard for modeling and execution
in thiscontextmeans:
Payment example
Pa
ym
en
t se
rvic
e
Orchestration is part of the microservices!O
rde
r se
rvic
e
Eventbus
It does not have to be one monlithic process
Hint: This might work well if your company is structured tohave this one clear process owner for this process.
Microservice vs. BPM community
Requirement: lightweight and embeddable engine
Engine must be
• easy to use
• developer friendly
also in the scope of microservices
• technically
• license model
Payment service
Order service
engine
engine
…
…
…
…
engine
Yes – that‘s possible!
LiveDemo
Architecture
Inventoryservice
Payment service
Order service
Shippingservice
H2
Shop Monitor
Camunda Webapp
on Tomcat
for demo in single Java VM for simplicity
Screenshots
Screenshots
And synchronous communication?
Communication between Microservices
Microservice Microservice
Microservice
A B
C
e.g. REST
You need to handle outtages (wait, retry, …)
Change scenarios
We want to reservegoods even before wereceived the payment.
Changes
Inventory service
Payment service
Order service
Shipping service
must providereservation
servicereserve goods at right moment
BPMN
Changes
Inventory service
Payment service
Order service
Shipping service
must providereservation
servicereserve goods at right moment
Listen to goodsreserved insteadof order created.
Listen to ordercreated.
With event commandtransformation
Without
VIP customers can order with invoice (and pay later)
Required changes
Inventory service
Payment service
Order service
Shipping service
Invoice service
skip payment, but add open invoice
Responsibility of order service
Required changes
Inventory service
Payment service
Order service
Shipping service
Invoice service
skip payment, but add open invoice
Listen to ordercreated VIP or
payment received(non VIP).
Listen to ordercreated (VIP).
We need more cool stuff – can BPMN do this?
Compensation
…in case of errors in error handling pay the
money back to thecustomer
Timeouts…after two weeks
pricing is not bindingany more
When a customer cancels, we want to win him back!
Required changes
Inventory service
Payment service
Order service
Shipping service
Listen toappropriate
events, no changeanywhere else
Winback service
BPM monolith
Summary
• Microservices and event driven architecture go well together
• You need an event command transformation
• If the translation is stateful, consider using an appropriate engine
• Modern lightweight engines foster and not hinder these architectures
Is it for me?Isn‘t all of that just for FANG?
Thank you! Any questions?
