Consumer-Driven Contracts with Pact (Sydney API Days 2015)
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Pacts to the rescue! Making your microservices play nicely together with Consumer Driven Contracts Beth Skurrie @bethesque / @pact_up [email protected]
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Transcript of Consumer-Driven Contracts with Pact (Sydney API Days 2015)
Pacts to the rescue!Making your microservices play nicely together
with Consumer Driven Contracts
Beth Skurrie@bethesque / @[email protected]
“Integrated tests are a scam. A self replicating virus that threatens the very health of your codebase, your sanity, and I'm not exaggerating when I say, your life.”
- JB Rainsberger
Integrated Tests: The Problems
! Slow! Easy to break! Hard to fix! Scales combinatorially
3 classes, 4 code paths each4 * 4 * 4 = 64 tests
A B
mock
Test Symmetry… how it works
Test 1
Test 2
Test 3
Integrated tests
! Lack of automated tools! Relies on developer eternal vigilance! Does not scale
Test Symmetry: The Problem
Do we have the technology to achieve test symmetry?
Posed to DiUS
Slower Easier to break
Harder to fix Scales BADLY
Lots of infrastructure
False negativesLots of set up
System Integration Tests
Pact to the rescue!!!
A B
mock
C P
pact
Pact… how it works
Slower Easier to break
Harder to fix Scales BADLY
Lots of infrastructure
False negativesLots of set up
System Integration Tests
Fast Stable
Easy to debug Reliable
No extra infrastructure
Low setupScales linearly
Pact
Better API design!
Arrange - set up mock server
Arrange - set up mock server
Arrange - set up mock server
Arrange - set up expectations
Arrange - set up expectations
Arrange - set up expectations
Act and Assert
Act and Assert
Act and Assert
Act and Assert
Act and Assert
Set up test data
Consumer assumed:
Provider complies:
Set up test data
Consumer assumed:
Provider complies:
Verify: Fail
Verify: Success!
Postel’s law
Sharing pacts
P
publish pact latest pact
C
Pact Broker
Pact Broker - Share pacts
Pact Broker - Autogenerated documentation
Pact Broker - Network graph
Support
! JSON is language independent! Ruby! JVM (Java and Scala)! .net! Javascript (consumer side, provider side WIP)! Pact specification
“How is it working for you?”
Fast feedback in isolation +
Early detection +
Rapid recovery
Pact allows you to:
! Combine the advantages of integrated tests and test symmetry! Mitigates the shortcomings of each method! Allows you to modify components with agility - quick feedback
on potential breakages! Have confidence that all the services in your system will work
together! Throw away your integration tests!!!
PactMakes your microservices play nicely together with Consumer Driven Contracts
github.com/realestate-com-au/pact@pact_up
Beth [email protected] @bethesque
• Regular expressions & type based matching
• Why doesn’t Pact use JSON Schema?
• How to avoid versioning APIs • How to use Pact between teams • Should I use Pact for testing external APIs?
• How not to do it • And moar!
