Spring Boot Consumer Driven Contract Demo

This project is written to attempt to understand more about Consumer Driven Contract with the use of Spring Boot + Pact / Spring Cloud Contract

Spring Boot Consumer Driven Contract Demo

Goal

Basic understanding and setup of Pact consumer / provider
Basic understanding and setup of Pact server
Basic understanding and setup of SCC provider / consumer
HTTP contract test for Pact
Messaging contract test for Pact
HTTP contract test for SCC
Messaging contract test for SCC
Using SCC with Pact Broker

Project

This repository includes four distinct sub-project;

pact-consumer
pact-provider
- Provides two API
  - GET /profiles
  - GET /profiles/{id}
scc-provider
scc-consumer

Run

Navigate to the individual directory and run

./gradlew bootRun

Build

Navigate to the individual directory and run

./gradlew [clean] build

Pact CDC

Broker

As mentioned earlier, without using Broker, we need to transfer the generated contract from the Consumer to Provider manually. However, with Broker, we can simply ask the Consumer to publish the contracts to Broker, and the Provider will read and verify the contracts from the Broker. This allows for even more seamless integration test and the Broker also has UI to view the result

To startup the broker, navigate to root directory and run

docker-compose up -d

Access via http://localhost:9292

Known Issue

Since au.com.dius.pact.consumer:junit5:4.3.0 onwards, when running the test, it will throw error java.lang.UnsupportedOperationException: Method getSingleProfile does not conform required method signature 'public au.com.dius.pact.core.model.V4Pact xxx(PactBuilder builder)'
- See test-report, most likely related to this issue and this note
- To overcome this, we can change to PactSpecVersion.V3 like such @PactTestFor(providerName = "ProfileProvider", pactVersion = PactSpecVersion.V3)
- Seem like PactSpecVersion.V4 is the default, and is incompatible with V3
When running the test via VSCode (manual click), pact generated contract will be output to target/pact even though using gradle. However, if running via command ./gradlew build, there won't be such issue
Unable to publish verification result to broker after running ./gradlew pactVerify command. Have reported the issue.
- Managed to get the result published after some help but still facing issue when using with gradle plugin

Spring Cloud Contract CDC

Known Issue

start.spring.io wrongly generated contracts as task instead of extension for gradle

Consideration

Consumer Driven Contract [Pact] vs Provider Driven Contract [SCC]
Ease of use
Learning curve / Overhead

Developer Experience

Documentation

Both libraries don't provide the best out-of-the-box experience to start as the documentation seem to jump all around, and are quite confusing (sometimes)

Tooling Support

So far, I am using gradle to test in my demo, and online is lacking on the support for gradle. Most of the example are written using maven, and my attempt to use gradle has faced multiple issues.
- Especially when an error occurs, it wasn't quite clear of what exactly is happening. I have to enable --info or --debug to see what exactly is the issue
- One example was when using SCC, in my contract, I did not enclose the response.body.email with quotes, but the error was pointing at Line 5 of the getAllProfiles.groovy file which was the start of the contract and was able to know when I turn on --debug mode
To be fair, if I had chose to use maven, the experience should have been better

Features

In Pact, consumer writes what fields are required in the contract before submitting, and provider run against it
In SCC, provider provides the stub and consumer run against the stub, then verify if the fields they need are there
In SCC, it seem less straightforward to write contract against Date

Further exploration

Possibly look into using Spring Cloud Contract with pact-broker Look into scc-multiapi-converter

Sample

spring-cloud-contract-sample

bwgjoseph / spring-boot-consumer-driven-contract-demo Goto Github PK