This sample project demonstrates how we can practice contract-driven development and contract testing in a GO application that depends on an external domain service and Kafka. Here, Specmatic is used to stub calls to domain API service based on its OpenAPI spec and mock Kafka based on its AsyncAPI spec.
Here is the domain api contract/open api spec
Here is the AsyncAPI spec of Kafka that defines the topics and message schema.
- BFF: Backend for Front End
- Domain API: API managing the domain model
- Specmatic Stub/Mock Server: Create a server that can act as a real service using its OpenAPI or AsyncAPI spec
A typical web application might look like this. We can use Specmatic to practice contract-driven development and test all the components mentioned below. In this sample project, we look at how to do this for GO BFF which is dependent on Domain API Service and Kafka demonstrating both OpenAPI and AsyncAPI support in specmatic.
- Go (Gin)
npm install specmatic
This will start the Go BFF server
go run cmd/main.goNote: When running this command you might get an error:
Could not find in. specmatic: specmatic-kafka:0.xx.yy.You would have got this error because you don't have access to Specmatic Kafka. To fix this issue, reach out to us at [email protected] and we'll add you to our beta program and provide you access.
Access find orders api at http://localhost:8080/findAvailableProducts Note: Unless domain api service is running on port 9000, above requests will fail. Move to next section for solution!
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Download Specmatic Jar from github
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Start domain api stub server
java -jar specmatic.jar stubAccess find orders api again at http://localhost:8080/findAvailableProducts with result like
[{"id":698,"name":"NUBYR","type":"book","inventory":278}]This will start the specmatic stub server for domain api using the information in specmatic.json and run the integration tests that expects the domain api at port 8090.
make integration_testsOR
go test -v ./internal/tests/... -count=1