JS_WORKFLOWS.md

JavaScript Workflows (Experimental)

⚠️ This feature is highly experimental and subject to change.

Overview

The CLI supports defining Conductor workflows using JavaScript instead of JSON. This allows you to write workflows in a more programmatic way with helper functions and inline task definitions.

Requirements

Your JavaScript file must define a workflow() function that returns an object containing:

• name: Workflow name
• description: Workflow description
• version: Workflow version number
• tasks: Array of task definitions
• inputParameters: (optional) Array of input parameter names
• outputParameters: (optional) Output parameter mappings

Creating a JavaScript Workflow

conductor workflow create workflow.js --js

The --js flag tells the CLI to process the file as JavaScript.

Example Workflow

function workflow() {
    return {
        name: "my_js_workflow",
        description: "Sample JS Workflow",
        version: 1,
        tasks: [
            {
                name: "process_data",
                taskReferenceName: "process_data_ref",
                type: "SIMPLE",
                inputParameters: {
                    data: "${workflow.input.data}"
                }
            },
            {
                name: "inline_fn",
                type: "INLINE",
                inputParameters: {},
                function: function transform() {
                    return {
                        result: "transformed"
                    };
                }
            },
            {
                // WAIT task - taskReferenceName auto-generated from name
                type: "WAIT",
                duration: "30s"
            },
            {
                name: "final_task",
                type: "SIMPLE",
                inputParameters: {
                    input: "${inline_fn.output.result}"
                }
            }
        ],
        inputParameters: ["data"],
        outputParameters: {
            result: "${final_task.output}"
        }
    };
}

Special Features

Inline Functions

You can define inline JavaScript functions that will be automatically converted to INLINE tasks with GraalJS evaluator:

{
    name: "inline_fn",
    type: "INLINE",
    inputParameters: {},
    function: function myFunction() {
        // Your JavaScript code here
        return {
            result: "some value"
        };
    }
}

The transformation will:

1. Convert the task type to "INLINE"
2. Stringify the function and set it as the expression parameter
3. Set evaluatorType to "graaljs"

WAIT Tasks

For WAIT tasks, you can simply specify the duration:

{
    type: "WAIT",
    duration: "30s"
}

The transformation will:

1. Auto-generate the task name as "WAIT" if not provided
2. Move duration to inputParameters.duration

Auto-generated Task References

If you don't provide a taskReferenceName, it will be automatically generated from the task name.

How It Works

When you run conductor workflow create workflow.js --js, the CLI:

1. Loads your JavaScript file
2. Executes the workflow() function in a JavaScript VM (goja)
3. Applies transformations to the returned object:
   • Converts inline functions to INLINE tasks
   • Processes WAIT tasks
   • Auto-generates missing taskReferenceNames
4. Converts the result to JSON
5. Registers the workflow with Conductor

Limitations

• The JavaScript runtime is sandboxed (goja)
• No access to Node.js modules or external dependencies
• Only the workflow() function is executed
• Error handling is basic - syntax errors may not be clearly reported

Updating Workflows

To update an existing JavaScript workflow:

conductor workflow update workflow.js --js

Tips

1. Always initialize inputParameters: {} for tasks with inline functions
2. Test your JavaScript syntax before uploading
3. Use descriptive task names for better readability
4. Remember that this is experimental - fallback to JSON if you encounter issues