petstore

Zilla Petstore using OpenAPI 3.x & AsyncAPI 3.x

This is an implementation of the common Petstore example where requests are proxied to Kafka. Zilla is implementing the REST endpoints defined in an OpenAPI 3.x spec and proxying them onto Kafka topics defined in an AsyncAPI 3.x spec based on the operations defined in each spec.

Watch the Walkthrough

Petstore Architecture Diagram

Without Zilla

flowchart LR
    style app1 stroke-dasharray: 5 5,stroke-width:4px
    style app2 stroke-dasharray: 5 5,stroke-width:4px

    ui[\Web/] -.- |HTTP| psws


    subgraph app2 [Petstore Event source/sink]
            krp{{Kafka REST Proxy}} --- krpp[produce] & krpc[consume]
    end

    subgraph app1 [Petstore Backend]
            psws{{OpenAPI Web Server}} --- | basic auth | krp
    end

    subgraph cc [Confluent Cloud]
        ccps[[Petstore Kafka Cluster]]
        krpp -.- ccps
        krpc -.- ccps
    end

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With Zilla

flowchart LR
    style app1 stroke:#0d9b76,stroke-width:4px

    ui[\Web/] -.- |HTTP| zpsos

    subgraph app1 [Zilla Petstore]
            zpsos{{OpenAPI REST}} --- zpp[produce] & zpc[consume]
    end

    subgraph cc [Confluent Cloud]
        ccps[[Petstore Kafka Cluster]]
        zpp -.- ccps
        zpc -.- ccps
    end

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Run the demo locally

The local demo uses a docker-compose.yaml setup and can be started running the setup.sh script. Running this script again will only restart the zilla service.

This demo implements two different versions of the Petstore API example. You can set the PETSTORE_VERSION env var as v1 or v2 with the setup script to change between the deployed versions.

v1	apicurio registry url
petstore-openapi-v1.yaml	petstore-openapi/versions/v1
petstore-kafka-asyncapi-v1.yaml	petstore-asyncapi/versions/v1

v2	apicurio registry url
petstore-openapi-v2.yaml	petstore-openapi/versions/v2
petstore-kafka-asyncapi-v2.yaml	petstore-asyncapi/versions/v2

PETSTORE_VERSION=v2 ./setup.sh

Generate jwt token

Use this script from the root directory of this demo to generate a JWT for authenticating your REST client.

docker run --rm -v ./private.pem:/private.pem bitnami/jwt-cli encode \
    --alg "RS256" \
    --kid "example" \
    --iss "https://auth.example.com" \
    --aud "https://api.example.com" \
    --exp=+7d \
    --no-iat \
    --payload "scope=read:all write:all write:pets read:pets" \
    --secret @private.pem \
    | pbcopy

Using the Petstore APIs

The Zilla Petstore is an HTTP Kafka proxy and exposes common entity CRUD endpoints with the entity data being stored on Kafka topics. Leveraging Kafka's cleanup.policy=compact feature, Zilla enables a standard REST backend architecture with Kafka as the storage layer. A UUID is generated for created objects and used as the Kafka message key.

Generate a REST client

Use your favorite REST client with either OpenAPI spec to generate an interface into this demo. You can also fork our Public postman collection which is generated using the petstore-openapi-v2.yaml.

Synchronous APIs

Both the /pet and /store/order endpoints all proxy to Kafka synchronously meaning they will behave like a normal rest endpoint where the message persists on a kafka topics

• The petstore-pets Kafka topic will have all the pets you posted, updated, and deleted.
• The petstore-orders Kafka topic will have all the order you posted or deleted.

Asynchronous APIs

The /customer endpoint is an asynchronous endpoint meaning it will success with a 202 ACCEPTED response and include a Location header that will include the correlation id used in the /customer;cid={correlationId} endpoint.

• The petstore-customers Kafka topic will have all the pending customer object you posted with a zilla:correlation-id header on the kafka message.
• The petstore-verified-customers Kafka topic will have all the verified customers and will need to include a matching zilla:correlation-id header to align with the message on the initial topic.

Here is an example using kcat to produce the correlated message:

echo '{"id":200000,"username":"fehguy","status":"approved","address":[{"street":"437 Lytton","city":"Palo Alto","state":"CA","zip":"94301"}]}' | \
    kcat -P \
         -b localhost:9092 \
         -k "c234d09b-2fdf-4538-9d31-27c8e2912d4e" \
         -t petstore-verified-customers \
         -H "zilla:correlation-id={correlationId}"

Teardown the environment

./teardown.sh