External Task list for Serverless Workflow

This project demonstrates an integration strategy for delegating tasks to an external system for processing. The workflow seamlessly incorporates the results returned by the external system to dynamically adjust subsequent execution steps.

The core of this project is a single-page application (SPA) that simulates the behavior of the external system. This SPA features a user-friendly task list interface. Users can select a task from the list and then provide a string-based result upon completion. This simulated environment allows for thorough testing and evaluation of the task delegation and result handling mechanisms within the workflow.

Caution

This application is a Proof of Concept and deliberately designed not to scale out. It must run as a single instance and isn't resilient to restart. In fact, the data store and event distribution (SSE) are kept in memory.

Run the demo locally

Launch Serverless Workflow engine

Launch the Serverless Workflow engine:

cd swf
kn workflow run

Launch the task list in dev mode

In a separate terminal window:

./mvnw quarkus:dev -Ddebug=5006 -DskipTests

Note

to avoid port conflicts, the application uses the port 8081 for HTTP protocol and 5006 for the debugging agent.

Showcase

1. Open the Serverless Workflow web console.

2. Select Workflow Definitions tab

   • Optionally, set input information to be passed down to the external task application. E.g. { "input": "approve the related documentation" }

3. Start tasker workflow definition using the "play" icon.

   • Check the workflow instance status: it's waiting for the external task execution.

4. Open the task list application

   • Type ok in the result field.
   • Click the complete button.

5. In the Serverless Workflow web console, check the workflow progress: the external task is completed and the workflow follow the correct path.

6. Optionally, check the Serverless Workflow log to verify the result of the external task.

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This project uses Quarkus, the Supersonic Subatomic Java Framework.

If you want to learn more about Quarkus, please visit its website: https://quarkus.io/.