Consumer-driven contracts: avoid microservices integration hell! (LondonCD - Oct 2016)
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Consumer-driven contracts Avoid microservices integration hell! @PierreVincent Oct 11th, 2016
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Transcript of Consumer-driven contracts: avoid microservices integration hell! (LondonCD - Oct 2016)
Consumer-driven contractsAvoid microservices integration hell!
@PierreVincent
Oct 11th, 2016
Pierre VincentTechnical Team Lead at Newsweaver
techblog.newsweaver.com
@PierreVincent
From this... … to this.
Login
Service
User
ServiceAPI
GET /users/pierre
{
"user": "pierre",
"name": "Pierre Vincent",
"role": "publisher"
}
200 OK
How do we test this?
Running in ProdTests Pass in
Build
Implement
changes
Deployed in
Prod
User
Service
Login
Service
!
✓ ✓ ✓ ✓
✓
{
...
"role": "editor"
}
{
...
"roles": ["publisher","editor"]
}
Running in Prod
✓ ✓
Maybe we should have tested before deploying to
production…?
Tested what though?
Users
Service
Login
Service
IP
Check
Service
Token
Gen
Service
Cert/Key
Service
Login
Frontend
We only wanted to
test this bit!
Contract
Login
Service
User
ServiceAPI
Authentication Team Users Team
[docs.pact.io]
PACT Specification
Verification philosophy: Tolerant Reader
Implementation guidelines
Implementations
Login
Service
User
Service
A
P
I
Pact
Mock
Server
Authentication Team Users Team
Pact
Consumer
Unit Test
Define
interaction
Trigger
interaction
Generate
Pact
Pact
Provider
Test
Share
Pact
Replay
interaction
Replay & Verify
Play &Record
Consumer
Provider
Assumption
Request
Expected
Response
Login Service
User Service
Given that user 'pierre' exists
Method GET
Path /users/pierre
Headers
Accept: application/json
Status 200
Headers
Content-Type: application/json
Body
{
"user": "pierre",
"name": "Pierre Vincent",
"role": "publisher"
}
Interaction
Authentication
Dev Team
Users
Dev Team
CMS
Dev Team
Billing
Dev Team
Pact
Broker
PACTPACT
PACTPACT
PACTPACT
PACTPACT
PACT
PACT
Pact
Broker
DependencyGraphs
Living documentation by example
✓ Versioning
✓ Tagging
✓ REST Api
Build/Deployment Pipeline integration
Provider pipeline
Implement changes Get Pacts from BrokerReplay & Verify
Interactions
Deploy Service
Build
Deploy to EU
PROD-EU
Get Pacts from BrokerReplay & Verify
Interactions
Stop deployment of incompatible Provider
Stop introduction of breaking change
PROD-US
PROD-EU
Consumer pipeline
Implement
changes
Generate Pacts
(Build)
Push Pacts to
BrokerTag Pacts
Each Provider verifies Pacts Deploy Service Tag Pacts
Build
Deploy to EU
HEAD
Stop deployment of incompatible Consumer
HEAD
PROD-EU
Caution: side-effects may include teams
collaborating on API design
Provider state setup for each interaction
Confidence comes from coverage:
don’t limit to happy paths
Automation within
deployment pipeline isn’t trivial
What’s the catch…?
After 2 years of CDCs...
Increased confidence when coding & deploying
✓Collaborative API design
✓Living API documentation
✓
Pact docs.pact.io, github.com/pact-foundation
Pact Broker github.com/bethesque/pact_broker
Try it out!
“Pact Matrix” (Beth Skurrie) rea.tech/enter-the-pact-matrix-or-how-to-decouple-the-release-
cycles-of-your-microservices
Why should you use CDC for microservices integration tests
techblog.newsweaver.com/why-should-you-use-consumer-driven-contracts-for-microservices-
integration-tests
Sharing CDCs with Pact Broker
techblog.newsweaver.com/sharing-consumer-driven-contracts-with-pact-broker
More reading...
techblog.newsweaver.com
Questions?
@PierreVincent
