Kogito Serverless Workflow - Rest Example

Description

This example contains a workflow that performs two consecutive REST invocations defined as functions.
The workflow is described using JSON format as defined in the CNCF Serverless Workflow specification.

The workflow expects a JSON input containing a collections of numbers.

The workflow starts invoking a GET to obtain a random integer. This integer is passed together with the list of numbers to a second REST invocation, a POST, which multiply each element of the array by the generated number and returns the sum. Finally, the resulting integer is printed using sysout script.

Installing and Running

Prerequisites

You will need:

• Java 17+ installed
• Environment variable JAVA_HOME set accordingly
• Maven 3.9.6+ installed

When using native image compilation, you will also need:

• GraalVm 20.2.0+ installed
• Environment variable GRAALVM_HOME set accordingly
• Note that GraalVM native image compilation typically requires other packages (glibc-devel, zlib-devel and gcc) to be installed too. You also need ‘native-image’ installed in GraalVM (using ‘gu install native-image’). Please refer to GraalVM installation documentation for more details.

Compile and Run in Local Dev Mode

mvn clean package quarkus:dev

Compile and Run in JVM mode

mvn clean package 
java -jar target/quarkus-app/quarkus-run.jar

or on Windows

mvn clean package
java -jar target\quarkus-app\quarkus-run.jar

Compile and Run using Local Native Image

Note 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/sw-quarkus-greeting-{version}-runner

Submit a request

The service based on the JSON workflow definition can be access by sending a request to http://localhost:8080/RESTExample' with following content

{
  "inputNumbers": [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    7
  ]
}

Complete curl command can be found below:

curl -X POST -H 'Content-Type:application/json' -H 'Accept:application/json' -d '{"inputNumbers": [1,2,3,4,5,6,7,8,7]}' http://localhost:8080/RestExample

Log after curl executed:

{
  "inputNumbers": [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    7
  ]
}

In Quarkus you should see the log message printed:

The sum is: 387