Ramzus / pact-kafka-demo

Using PACT with Kafka and Schema Registry

Setup - PACT broker

This section will get you a PACT broker up and running locally, on port 9292. You need docker and docker-compose. From the command line:

docker-compose up

The PACT broker will now be reachable at: http://localhost:9292/

Run the consumer tests from the IDE

This will generate the PACTs, and the files will be found under target/pacts

Publish the PACTs to the broker:

mvn pact:publish

(Take a look on http://localhost:9292/)

Run the provider tests from the IDE

Note: They will read the PACTs from the broker but not publish their results to it

Run the provider tests from maven:

This will publish the provider test results to the broker:

mvn verify -Dpact.verifier.publishResults=true

(note the green and red fields on the broker)

The tests

These tests demonstrate how PACT deals with "messaging", as opposed to the more traditional (or at least, longer supported) HTTP Request-Response pairs.

The tests in the [consumer|provider].kafka package show:

• a Kafka message with a JSON payload/value
• a Kafka message with a Schema Registry verified JSON payload/value
• a normal JSON consumer against a schema registry provider (failure!)

The tests also demonstrate some shortcomings. As the messaging layer from PACT does not involve you actually using that messaging from the tests (unlike the HTTP implementation), we can get tests to pass in strange ways:

• We could have a consumer application listening on a websocket.
• We could have a provider application writing to Kafka. and we can make the tests pass. Obviously, this would never work in reality, sad