Migrate to RHAPSODY by AymenFJA · Pull Request #68 · radical-cybertools/radical.asyncflow

AymenFJA · 2026-02-12T17:55:29Z

This PR removes the execution backends from AsyncFlow and relies on RHAPSODY for AI-HPC execution.

AsyncFlow will no longer have execution capabilities; instead, it will be a higher entity that controls RHAPSODY and orchestrates a large scale of async workflows with complex dependencies while offloading the task execution to RHAPSODY.

From a migration perspective, the application-level frameworks such as ROSE, IMPRESS, DDSim, and FACTs will require at least 1 line of code change.

gemini-code-assist · 2026-02-12T18:00:49Z

Summary of Changes

Hello @AymenFJA, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request represents a significant architectural shift for AsyncFlow, transitioning it from a system with internal execution capabilities to a dedicated workflow orchestration layer. By removing its own execution backends and integrating with RHAPSODY, AsyncFlow can now leverage RHAPSODY's specialized AI-HPC execution features, allowing AsyncFlow to focus on managing complex dependencies and workflow logic more effectively.

Highlights

Execution Backend Removal: Removed all internal execution backends, including Concurrent, Dask, and Radical Pilot, from AsyncFlow.
RHAPSODY Integration: Migrated AsyncFlow to rely entirely on the external RHAPSODY framework for AI-HPC task execution.
Architectural Refocus: Refactored AsyncFlow to function as a high-level orchestrator for complex asynchronous workflows, delegating execution concerns.
Noop Backend Simplification: Simplified and decoupled the NoopExecutionBackend, moving it to a standalone module and removing its dependency on the old base backend and state management.

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Changelog

src/radical/asyncflow/init.py
- Removed imports and exports for ConcurrentExecutionBackend, DaskExecutionBackend, and RadicalExecutionBackend.
- Updated the import path for NoopExecutionBackend.
src/radical/asyncflow/backends/execution/base.py
- Removed the BaseExecutionBackend abstract class and the Session class.
src/radical/asyncflow/backends/execution/concurrent.py
- Removed the ConcurrentExecutionBackend implementation.
src/radical/asyncflow/backends/execution/dask_parallel.py
- Removed the DaskExecutionBackend implementation.
src/radical/asyncflow/backends/execution/radical_pilot.py
- Removed the RadicalExecutionBackend implementation.
src/radical/asyncflow/constants.py
- Removed the TasksMainStates enum and the StateMapper class.
src/radical/asyncflow/noop_executor.py
- Renamed the file from src/radical/asyncflow/backends/execution/noop.py.
- Refactored NoopExecutionBackend to be a standalone class, no longer inheriting from BaseExecutionBackend.
- Introduced NoopSession and NoopStateMapper classes within the file.
- Removed the registration of backend states with the global StateMapper.
src/radical/asyncflow/workflow_manager.py
- Removed the import of BaseExecutionBackend.
- Updated the import path for NoopExecutionBackend.
- Modified the type hint for the 'backend' parameter in WorkflowEngine's constructor to be generic.
tests/integration/test_workflow_failures.py
- Removed the import of ThreadPoolExecutor.
- Updated the import of ConcurrentExecutionBackend to use 'rhapsody.backends.execution'.
- Removed the ThreadPoolExecutor argument during ConcurrentExecutionBackend instantiation.
tests/integration/test_workflow_runs_to_completion.py
- Removed the import of ThreadPoolExecutor.
- Updated the import of ConcurrentExecutionBackend to use 'rhapsody.backends.execution'.
- Removed the ThreadPoolExecutor argument during ConcurrentExecutionBackend instantiation.
tests/unit/test_data_dependencies.py
- Removed the import of ThreadPoolExecutor.
- Updated the import of ConcurrentExecutionBackend to use 'rhapsody.backends.execution'.
- Removed the ThreadPoolExecutor argument during ConcurrentExecutionBackend instantiation.
tests/unit/test_dependencies_resloution.py
- Removed the import of ThreadPoolExecutor.
- Updated the import of ConcurrentExecutionBackend to use 'rhapsody.backends.execution'.
- Removed the ThreadPoolExecutor argument during ConcurrentExecutionBackend instantiation.
tests/unit/test_failure_propagation.py
- Removed the import of ThreadPoolExecutor.
- Updated the import of ConcurrentExecutionBackend to use 'rhapsody.backends.execution'.
- Removed the ThreadPoolExecutor argument during ConcurrentExecutionBackend instantiation.

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Code Review

This pull request undertakes a significant migration to offload execution capabilities to RHAPSODY, which is reflected by the removal of the internal execution backend implementations. The changes in the test files correctly adapt to this by using the ConcurrentExecutionBackend from rhapsody.

However, the refactoring appears to be incomplete in src/radical/asyncflow/workflow_manager.py. While the import for BaseExecutionBackend has been removed, it is still referenced as a type hint in the create and _setup_execution_backend methods. This will cause a NameError at runtime and is a critical issue that needs to be addressed. These methods need to be updated to remove the dependency on the now-deleted BaseExecutionBackend.

Additionally, I've left a specific comment regarding a removed type hint in WorkflowEngine.__init__ that should be restored for code clarity.

gemini-code-assist · 2026-02-12T18:15:02Z

src/radical/asyncflow/workflow_manager.py

    def __init__(
        self,
-        backend: BaseExecutionBackend,
+        backend,


The type hint for the backend parameter has been removed. While the old BaseExecutionBackend is no longer applicable, it's good practice to maintain type hints for clarity and static analysis. Please add a type hint for the backend. If there isn't a specific base class from RHAPSODY to use, typing.Any would be a suitable replacement for now.

Suggested change

backend,

backend: Any,

into rhapsody. Asyncflow now ships only NoopExecutionBackend and LocalExecutionBackend in a single backends.py module. External backends (e.g. from rhapsody) plug in via simple import. Also fixes missing cloudpickle import, stale type annotations, and updates all tests to use asyncflow's LocalExecutionBackend.

review-notebook-app · 2026-02-12T23:15:36Z

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@task

1-Add prompt_task 2-Add support for concurrent backends 3-Add explicit task routing via @task(backend='..')

follow similar approach to feature/rhapsody but with less code changes

7cdb7bb

AymenFJA self-assigned this Feb 12, 2026

AymenFJA added internal priority:critical topic:api topic:execution type:feature type:refactor labels Feb 12, 2026

gemini-code-assist bot reviewed Feb 12, 2026

View reviewed changes

AymenFJA added 3 commits February 12, 2026 23:43

update tox

85cb8ee

adding pre-commit

f7a5d27

AymenFJA added 7 commits February 13, 2026 00:18

add pre-commit to test workflow

1b56d6f

fix pre-commit

f8bfca0

update docs/examples with new changes

d252324

cleanup

3805640

adding changelog

7a7f215

bump version and update change log

ebe0d78

precommit

3ac0585

AymenFJA mentioned this pull request Feb 15, 2026

Add PRE-COMMIT and CHANGELOG.md l #63

Closed

AymenFJA added the Q1 label Feb 15, 2026

AymenFJA added 3 commits February 20, 2026 20:10

cleanup

5e52ee0

This commit:

e247969

1-Add prompt_task 2-Add support for concurrent backends 3-Add explicit task routing via @task(backend='..')

ruff

38e986a

AymenFJA mentioned this pull request Feb 21, 2026

Import backends from RHAPSODY #56

Closed

update README

be6659f

AymenFJA merged commit 2da8d9b into main Feb 24, 2026
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Migrate to RHAPSODY#68

Migrate to RHAPSODY#68
AymenFJA merged 15 commits intomainfrom
feature/rhapsody-2

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AymenFJA commented Feb 12, 2026

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