Your First Flow

Welcome to Jetty! In this guide, you'll create your first workflow using a simple echo task that demonstrates the core concepts of flows, steps, and path expressions. By the end of this tutorial, you'll understand how to:

• Create a new flow in the Jetty interface
• Configure workflow steps and activities
• Use path expressions to pass data between components
• Run your workflow and view the results

What We're Building

We'll create a simple "echo" workflow that takes a text input and outputs the same text. While basic, this example demonstrates all the fundamental concepts you'll use in more complex workflows.

Here's the complete flow configuration we'll be creating:

{
  "init_params": {
    "text": "hello, Jetty!"
  },
  "step_configs": {
    "hello": {
      "activity": "text_echo",
      "text_path": "init_params.text"
    }
  },
  "steps": [
    "hello"
  ]
}

Understanding the Flow Structure

Before we create the flow, let's understand each part:

init_params

Initial parameters that provide input data to your workflow. In our case:

• "text": "hello, Jetty!" - This sets up our input text that will be echoed

step_configs

Configuration for each step in your workflow. Our hello step includes:

• "activity": "text_echo" - Specifies which activity function to run
• "text_path": "init_params.text" - A path expression that tells the step where to find its input data

steps

An ordered list of step names to execute:

• ["hello"] - Execute only the "hello" step we configured above

Path Expressions Explained

The "text_path": "init_params.text" is a path expression - a powerful feature that lets you reference data from different parts of your workflow.

Path expressions follow the pattern: source.path.to.value

• init_params.text - Get the text value from the initial parameters
• step_name.outputs.result - Get a result from a previous step's output
• previous_step.inputs.prompt - Reference what was passed to a previous step

In our echo example, init_params.text retrieves the "hello, Jetty!" string we defined in the initialization parameters and passes it to the text_echo activity.

Step 1: Create a New Task

1. Navigate to Jetty and log in to your account
2. Click "Create Task" to start building your first workflow
3. Fill in the Basic Information:
   • Collection: Leave as your default collection (e.g., "jettyiodev")
   • Task Name: Enter echo-tutorial
   • Version: Leave as 1.0.0
   • Description: Enter "My first echo workflow to learn Jetty basics"

Step 2: Configure the Workflow

In the Workflow Configuration section, you'll see a JSON editor. Replace the default content with our echo flow configuration:

{
  "init_params": {
    "text": "hello, Jetty!"
  },
  "step_configs": {
    "hello": {
      "activity": "text_echo",
      "text_path": "init_params.text"
    }
  },
  "steps": [
    "hello"
  ]
}

What This Configuration Does:

1. Sets up input data - The init_params section defines our initial text
2. Configures a step - The hello step uses the text_echo activity
3. Uses a path expression - text_path tells the echo activity to get its input from init_params.text
4. Defines execution order - The steps array specifies that only the hello step should run

Step 3: Save and Run Your Flow

1. Click "Create Task" to save your workflow
2. Navigate to the "Run Flow" tab
3. Review the run parameters - You should see:

{
  "text": "hello, Jetty!"
}

# Sync execution (waits for completion)
curl -X POST "$JETTY_API_URL/api/v1/run-sync/jettyiodev/echo-tutorial" \
  -H "Authorization: Bearer $JETTY_API_TOKEN" \
  -F 'init_params={"text": "hello, Jetty!"}'

# Async execution (returns immediately)  
curl -X POST "$JETTY_API_URL/api/v1/run/jettyiodev/echo-tutorial" \
  -H "Authorization: Bearer $JETTY_API_TOKEN" \
  -F 'init_params={"text": "hello, Jetty!"}'

This makes it easy to integrate Jetty workflows into your applications, scripts, and automation pipelines.