A quickstart project that deals with traveller processing carried by rules. It illustrates how easy it is to make the Kogito processes and rules to work with Apache Kafka
This example shows
- consuming events from a Kafka topic and for each event start new process instance
- each process instance is expecting a traveller information in JSON format
- traveller is then processed by rules and based on the outcome of the processing (processed or not) traveller is
- if successfully processed traveller information is logged and then updated information is send to another Kafka topic
- if not processed traveller info is logged and then process instance finishes without sending reply to Kafka topic
- Diagram Properties (top)
- Diagram Properties (bottom)
- Diagram Properties (process variables)
- Start Message
- Start Message (Assignments)
- Process Traveler Business Rule (top)
- Process Traveler Business Rule (bottom)
- Process Traveler Business Rule (Assignments)
- Process Traveler Gateway
- Process Traveler Gateway Yes Connector
- Process Traveler Gateway No Connector
- Log Traveler Script Task
- Skip Traveler Script Task
- Processed Traveler End Message
- Processed Traveler End Message (Assignments)
- Skip Traveler End
This quickstart requires an Apache Kafka to be available and by default expects it to be on default port and localhost.
- Install and Startup Kafka Server / Zookeeper
https://kafka.apache.org/quickstart
You will need:
- Java 11+ installed
- Environment variable JAVA_HOME set accordingly
- Maven 3.8.6+ installed
When using native image compilation, you will also need:
- GraalVM 19.3+ installed
- Environment variable GRAALVM_HOME set accordingly
- GraalVM native image needs as well native-image extension: https://www.graalvm.org/reference-manual/native-image/
- Note that GraalVM native image compilation typically requires other packages (glibc-devel, zlib-devel and gcc) to be installed too, please refer to GraalVM installation documentation for more details.
mvn clean compile quarkus:devNOTE: With dev mode of Quarkus you can take advantage of hot reload for business assets like processes, rules, decision tables and java code. No need to redeploy or restart your running application.
mvn clean package
java -jar target/quarkus-app/quarkus-run.jaror on windows
mvn clean package
java -jar target\quarkus-app\quarkus-run.jarNote that this requires GRAALVM_HOME to point to a valid GraalVM installation
mvn clean package -Pnative
To run the generated native executable, generated in target/, execute
./target/process-kafka-quickstart-quarkus-runner
You can take a look at the OpenAPI definition - automatically generated and included in this service - to determine all available operations exposed by this service. For easy readability you can visualize the OpenAPI definition file using a UI tool like for example available Swagger UI.
In addition, various clients to interact with this service can be easily generated using this OpenAPI definition.
When running in either Quarkus Development or Native mode, we also leverage the Quarkus OpenAPI extension that exposes Swagger UI that you can use to look at available REST endpoints and send test requests.
To make use of this application it is as simple as putting a message on travellers topic with following content (cloud event format)
- To examine ProcessedTravellers topic and verify upcoming messages will be processed
Execute in a separate terminal session
bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic processedtravellers- Send message that should be processed to Topic
bin/kafka-console-producer.sh --broker-list localhost:9092 --topic travellersContent (cloud event format)
{
"specversion": "0.3",
"id": "21627e26-31eb-43e7-8343-92a696fd96b1",
"source": "",
"type": "travellers",
"time": "2022-02-24T13:25:16+0000",
"data": {
"firstName" : "Jan",
"lastName" : "Kowalski",
"email" : "[email protected]",
"nationality" : "Polish"
}
}One liner
{"specversion": "0.3","id": "21627e26-31eb-43e7-8343-92a696fd96b1","source": "","type": "travellers", "time": "2022-02-24T13:25:16+0000","data": { "firstName" : "Jan", "lastName" : "Kowalski", "email" : "[email protected]", "nationality" : "Polish"}}this will then trigger the successful processing of the traveller and put another message on processedtravellers topic with following content (cloud event format)
{
"specversion": "0.3",
"id": "86f69dd6-7145-4188-aeaa-e44622eeec86",
"source": "",
"type": "TravellersMessageDataEvent_3",
"time": "2019-10-03T16:22:40.373523+02:00[Europe/Warsaw]",
"data": {
"firstName": "Jan",
"lastName": "Kowalski",
"email": "[email protected]",
"nationality": "Polish",
"processed": true
},
"kogitoProcessinstanceId": "4fb091c2-82f7-4655-8687-245a4ab07483",
"kogitoParentProcessinstanceId": null,
"kogitoRootProcessinstanceId": null,
"kogitoProcessId": "Travellers",
"kogitoRootProcessId": null,
"kogitoProcessinstanceState": "1",
"kogitoReferenceId": null
}there are bunch of extension attributes that starts with kogito to provide some context of the execution and the event producer.
To take the other path of the process put following message on travellers topic
- Send Message that should be skipped to Topic
bin/kafka-console-producer.sh --broker-list localhost:9092 --topic travellersWith the following content (Cloud Event Format)
{
"specversion": "0.3",
"id": "31627e26-31eb-43e7-8343-92a696fd96b1",
"source": "",
"type": "travellers",
"time": "2022-02-24T13:25:16+0000",
"data": {
"firstName" : "John",
"lastName" : "Doe",
"email" : "[email protected]",
"nationality" : "American"
}
}One Liner
{"specversion": "0.3","id": "31627e26-31eb-43e7-8343-92a696fd96b1","source": "","type": "travellers", "time": "2022-02-24T13:25:16+0000","data": { "firstName" : "John", "lastName" : "Doe", "email" : "[email protected]", "nationality" : "American"}}this will not result in message being send to processedtravelers topic.
In the operator directory you'll find the custom resources needed to deploy this example on OpenShift with the Kogito Operator.