This document discusses using Spring Cloud Contract to help define contracts between microservices. It notes that without contracts, tests between services can break when implementations change. The document demonstrates coding a sample app to check ages for alcohol purchases, then generating contract stubs using Spring Cloud Contract. It addresses questions like storing contracts in a shared repo, generating stubs without writing scripts using WireMock and RestDocs, and learning more about Spring Cloud Contract.

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© 2016 Pivotal
Consumer Driven Contracts and
Your Microservice Architecture
Marcin Grzejszczak, @mgrzejszczak

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Spring Cloud developer at Pivotal
Working mostly on
● Spring Cloud Sleuth
● Spring Cloud Contract
● Spring Cloud Pipelines
About me
Twitter: @mgrzejszczak
Blog: http://toomuchcoding.com

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Introduction
Demo
Summary
Agenda

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What we will NOT be talking about?

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What we will NOT be talking about?
THE IDEA OF SPRING CLOUD
CONTRACT IS NOT TO
INTRODUCE UNNECESSARY
COUPLING OR REPLICATE OLD
MISTAKES

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Introduction

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Introduction
What problems are we trying to solve?

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Introduction
Typical situation
HTTP
CONSUMER PRODUCER

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Introduction
How to write a test for it?
HTTP
CONSUMER PRODUCER

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Introduction
How to write a test for it?
HTTP
CONSUMER PRODUCER

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Introduction
Stub validity & reusability
WE’RE ON THE CONSUMER SIDE!!
CONSUMER OWNS THE STUB
DEFINITIONS

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Introduction
Stub validity & reusability

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Introduction
Let’s assume that we’re introducing a new
endpoint...

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Introduction
Stub validity & reusability

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Introduction
So now what?

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Introduction
Ooops...

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Introduction
What went wrong?
HTTP
CONSUMER PRODUCER
TEST
OK
HTTP
CONSUMER PRODUCER
REALITY
WAT?!

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Introduction
Another example with messaging
CONSUMERPRODUCER
TEST
PRODUCER CONSUMER
REALITY
topic: bar topic: foo
topic: bar

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Introduction
Stub validity & reusability

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Introduction
Nice API creation

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Introduction
Nice API creation - no cooperation results

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Introduction
Nice API creation - no cooperation results

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Demo
Potential answer
Spring Cloud Contract

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Demo
What are we going to code?

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Demo
What are we going to code?

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Introduction
What are we going to code?
I’m 22 give me a beer
CONSUMER PRODUCER
There you go!
Can he get the beer?
Yes!

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Introduction
What are we going to code?
I’m 17 give me a beer
CONSUMER PRODUCER
Get lost!
Can he get the beer?
No!

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Introduction
What are we going to code?
Someone’s 22. Check him out!
CONSUMERPRODUCER
Positive verification took place
Messaging

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Introduction
What are we going to code?
Someone’s 17. Check him out!
CONSUMERPRODUCER
Negative verification took place
Messaging

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Introduction
What are we going to code?
BLACK TERMINAL
BLACK IDE
CONSUMER
WHITE TERMINAL
WHITE IDE
PRODUCER

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Demo

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Summary

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Summary
PRODUCER CONSUMER

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Summary
PRODUCER
CONSUMER
CLONES
PRODUCER
PRODUCER
CLONE CONSUMER

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Summary
PRODUCER CONSUMER
CONSUMER
CLONES
PRODUCER
PRODUCER
CLONE
INTERACTION

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Summary
PRODUCER CONSUMER
PRODUCER
CLONE
INTERACTION
CONSUMER FILES
A PR

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Summary

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Summary
PRODUCER
TAKES OVER THE PR

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Summary
PRODUCER
TAKES OVER THE PR
WRITES THE MISSING
IMPLEMENTATION

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Summary
PRODUCER
TAKES OVER THE PR
WRITES THE MISSING
IMPLEMENTATION
MERGES TO MASTER
CI UPLOADS TO NEXUS /
ARTIFACTORY

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Summary

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Summary
CONSUMER
SWITCHES TO
ONLINE MODE
DOWNLOADS STUBS OF
COLLABORATORS DURING
BUILD PHASE

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Summary

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Summary

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I don’t want to keep my contracts with the producer

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Demo

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Common repo with contracts - consumer
PRODUCER CONSUMER

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Common repo with contracts - consumer
PRODUCER CONSUMER
REPO WITH
CONTRACTS

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Common repo with contracts - consumer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
G
IT
C
LO
N
E
CLONED REPO
WITH
CONTRACTS

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Common repo with contracts - consumer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
G
IT
C
LO
N
E
CLONED REPO
WITH
CONTRACTS
INTERACTION

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Common repo with contracts - consumer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
CLONED REPO
WITH
CONTRACTSPR

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Common repo with contracts - producer
PRODUCER CONSUMER
REPO WITH
CONTRACTS

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Common repo with contracts - producer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
CLONED REPO
WITH
CONTRACTS
PR
O
D
U
C
ER
TAKES
O
VER
PR

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WRITES THE MISSING
IMPLEMENTATION
Common repo with contracts - producer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
CLONED REPO
WITH
CONTRACTS
PR
O
D
U
C
ER
TAKES
O
VER
PR

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WRITES THE MISSING
IMPLEMENTATION
Common repo with contracts - producer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
CLONED REPO
WITH
CONTRACTS
M
ER
G
E
PR

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WRITES THE MISSING
IMPLEMENTATION
Common repo with contracts - producer
PRODUCER CONSUMER
REPO WITH
CONTRACTS
CI UPLOADS TO NEXUS
/ ARTIFACTORY

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I don’t want to keep my contracts with the producer

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I don’t want to write any scripts!

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Introduction
Don’t worry! You can use Spring Cloud
Contract WireMock with Rest Docs!!

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Demo

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Summary

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Summary

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QUESTIONS

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mgrzejszczak