Hello World

This example creates a two-step workflow that greets someone and then shouts the greeting in uppercase.

Workflow file

Create workspace/.workflows/hello.yaml:

actions:
  greet:
    type: script
    script: "echo Hello {{ input.name }} && echo 'OUTPUT: {\"greeting\": \"Hello {{ input.name }}\"}'"
    input:
      name: { type: string, required: true }

  shout:
    type: script
    script: "echo {{ input.message }} | tr '[:lower:]' '[:upper:]'"
    input:
      message: { type: string, required: true }

tasks:
  hello-world:
    mode: distributed
    input:
      name: { type: string, default: "World" }
    flow:
      say-hello:
        action: greet
        input:
          name: "{{ input.name }}"
      shout-it:
        action: shout
        depends_on: [say-hello]
        input:
          message: "{{ say_hello.output.greeting }}"

What this does

1. greet action prints “Hello World” and emits structured output with OUTPUT: {json}
2. shout action takes a message and converts it to uppercase
3. hello-world task runs say-hello first, then passes its output to shout-it

The two steps form a dependency chain: say-hello → shout-it.

Key concepts demonstrated

• Actions define reusable commands with typed input parameters
• Tasks compose actions into a DAG via depends_on
• Structured output uses OUTPUT: {json} prefix in stdout
• Data passing uses Tera templates: {{ say_hello.output.greeting }}
• Step name sanitization: say-hello becomes say_hello in templates (hyphens → underscores)

Running it

# Via API
curl -s -X POST http://localhost:8080/api/workspaces/default/tasks/hello-world/execute \
  -H "Content-Type: application/json" \
  -d '{"input": {"name": "World"}}' | jq .

# Via CLI
stroem trigger hello-world --input '{"name": "World"}'

Expected output

Step say-hello:

Hello World
OUTPUT: {"greeting": "Hello World"}

Step shout-it:

HELLO WORLD