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Quick Start

This guide will help you run your first heterogeneous workflow using RHAPSODY in just a few minutes.

Core Concepts

Before we start, keep these three key objects in mind:

  1. Backend: Where your tasks actually run (e.g., your local CPU, a Dask cluster, or an HPC queue).
  2. Task: A unit of work. ComputeTask for binaries/scripts, or AITask for inference.
  3. Session: The manager that connects backends and tasks together.

Basic Workflow

Here is a complete script demonstrating a simple compute workflow.

import asyncio
import rhapsody
from rhapsody.api import Session, ComputeTask
from rhapsody.backends import ConcurrentExecutionBackend

async def run_example():
    # 1. Choose an execution backend (Concurrent uses local threads/processes)
    backend = await ConcurrentExecutionBackend(name="local")

    # 2. Open a session
    async with Session(backends=[backend]) as session:

        # 3. Define tasks
        tasks = [
            ComputeTask(executable="/bin/echo", arguments=[f"Task {i}"])
            for i in range(1024)
        ]

        # 4. Submit tasks to the session
        await session.submit_tasks(tasks)

        # 5. Wait for all tasks to complete
        results = await asyncio.gather(*tasks)

        # 6. Inspect results
        for t in tasks:
            print(f"{t.uid}: {t.state} (Output: {t.stdout})")

if __name__ == "__main__":
    asyncio.run(run_example())

Output

If everything is set up correctly, you should see: 

task.000001: DONE (Output: Task 0)
task.000002: DONE (Output: Task 1)
task.000003: DONE (Output: Task 2)
task.000004: DONE (Output: Task 3)
task.000005: DONE (Output: Task 4)
task.000006: DONE (Output: Task 5)
task.000007: DONE (Output: Task 6)
task.000008: DONE (Output: Task 7)
task.000009: DONE (Output: Task 8)
task.000010: DONE (Output: Task 9)
task.000011: DONE (Output: Task 10)
task.000012: DONE (Output: Task 11)
......
task.001021: DONE (Output: Task 1020)
task.001022: DONE (Output: Task 1021)
task.001023: DONE (Output: Task 1022)
task.001024: DONE (Output: Task 1023)
real    0m2.669s
user    0m2.384s
sys     0m2.071s

What's Next?