{"id":6507,"library":"aiotask-context","title":"aiotask-context Library","description":"The `aiotask-context` library provides a mechanism to store and retrieve context information within `asyncio.Task` objects. It is analogous to `threading.local` but designed for asynchronous Python applications, allowing for request-scoped or task-scoped data management without explicit parameter passing. The current version is 0.6.1, with a stable but infrequent release cadence.","status":"active","version":"0.6.1","language":"en","source_language":"en","source_url":"https://github.com/python-aiotask-context/aiotask-context","tags":["asyncio","context","task-local storage","concurrency","async"],"install":[{"cmd":"pip install aiotask-context","lang":"bash","label":"Install with pip"}],"dependencies":[],"imports":[{"note":"Since version 0.4.0, `context` is a pre-instantiated singleton object, not a class.","wrong":"from aiotask_context import Context","symbol":"context","correct":"from aiotask_context import context"}],"quickstart":{"code":"import asyncio\nfrom aiotask_context import context\n\nasync def nested_task(task_id: str):\n    \"\"\"A sub-task that accesses and modifies context.\"\"\"\n    request_id = context.get(\"request_id\")\n    print(f\"Task {task_id}: Retrieved request_id: {request_id}\")\n\n    # Set a task-specific value; this does not affect other tasks' contexts\n    # nor the parent task's context once the child task's context is copied.\n    context.set(\"task_data\", f\"Data from {task_id}\")\n    await asyncio.sleep(0.01) # Simulate async work\n    print(f\"Task {task_id}: Set task_data: {context.get('task_data')}\")\n\nasync def main():\n    print(\"--- aiotask-context Quickstart ---\")\n\n    # Set context in the main task\n    context.set(\"request_id\", \"req-xyz-123\")\n    print(f\"Main task: Initial request_id: {context.get('request_id')}\")\n\n    # Create and run sub-tasks. Each sub-task inherits a *copy* of the parent's context.\n    task1 = asyncio.create_task(nested_task(\"A\"))\n    task2 = asyncio.create_task(nested_task(\"B\"))\n\n    await task1\n    await task2\n\n    # The main task's context remains unchanged by sub-tasks' modifications\n    print(f\"Main task: Final request_id: {context.get('request_id')}\") # Should be 'req-xyz-123'\n    # Task-specific data set in sub-tasks is not accessible here in the main task\n    print(f\"Main task: task_data: {context.get('task_data')}\") # Should be None\n    print(\"This demonstrates task-local context isolation in asyncio.\")\n\nif __name__ == \"__main__\":\n    asyncio.run(main())","lang":"python","description":"This quickstart demonstrates how `aiotask-context` allows setting context variables that are isolated to the current `asyncio.Task`. Sub-tasks inherit a copy of their parent's context, and modifications within a sub-task do not affect the parent or sibling tasks, ensuring task-local storage."},"warnings":[{"fix":"Update your import statement from `from aiotask_context import Context` and remove any instantiation, using `context` directly instead.","message":"The package underwent a significant change in version 0.4.0. Prior to 0.4.0, `Context` was a class that needed to be instantiated (e.g., `c = Context()`). Since 0.4.0, `context` is a pre-instantiated singleton object directly imported (`from aiotask_context import context`).","severity":"breaking","affected_versions":"< 0.4.0"},{"fix":"Always refer to the official repository at `https://github.com/python-aiotask-context/aiotask-context` for the most up-to-date information, issues, and contributions.","message":"The project's GitHub repository and primary maintainership transitioned from `vimeo/aiotask-context` to `python-aiotask-context/aiotask-context`. While the package name on PyPI remains the same, older documentation or references might point to the outdated repository.","severity":"breaking","affected_versions":"All versions"},{"fix":"Understand that `aiotask-context` provides task-local storage, not global or shared state across tasks. If you need to communicate state *back* to a parent task, use standard asyncio mechanisms like `asyncio.Queue` or return values.","message":"Context in `aiotask-context` is strictly task-local. When `asyncio.create_task` is used, the child task inherits a *copy* of the parent's context. Any modifications made by the child task to its context will not reflect in the parent task's context or sibling tasks' contexts.","severity":"gotcha","affected_versions":"All versions"},{"fix":"For new projects on Python 3.7+, consider evaluating `contextvars` from the standard library. If using `aiotask-context`, be aware of its specific implementation and ensure it meets your requirements.","message":"`aiotask-context` is designed for task-scoped data and should not be confused with `contextvars` (PEP 567) introduced in Python 3.7. While both provide context management, `aiotask-context` predates `contextvars` and relies on direct manipulation of `asyncio.Task` internals. `contextvars` offers a more robust and officially supported way for context propagation.","severity":"gotcha","affected_versions":"All versions, especially Python 3.7+"}],"env_vars":null,"last_verified":"2026-04-15T00:00:00.000Z","next_check":"2026-07-14T00:00:00.000Z","problems":[{"fix":"Install the module using pip: 'pip install aiotask-context'.","cause":"The 'aiotask_context' module is not installed in the Python environment.","error":"ModuleNotFoundError: No module named 'aiotask_context'"},{"fix":"Use the correct import statement: 'from aiotask_context import get, set'.","cause":"Attempting to import a non-existent 'context' attribute from the 'aiotask_context' module.","error":"ImportError: cannot import name 'context' from 'aiotask_context'"},{"fix":"Use the correct function: 'from aiotask_context import get'.","cause":"The 'get_context' function does not exist in the 'aiotask_context' module.","error":"AttributeError: module 'aiotask_context' has no attribute 'get_context'"},{"fix":"You need to set the `aiotask-context` task factory for your event loop. For example: `loop = asyncio.get_event_loop()` followed by `loop.set_task_factory(context.task_factory)` or `loop.set_task_factory(context.copying_task_factory)`.","cause":"This error occurs when the `aiotask-context` task factory has not been properly set on the `asyncio` event loop, meaning tasks are created without the necessary 'context' attribute.","error":"AttributeError: '_asyncio.Task' object has no attribute 'context'"},{"fix":"Set a context-aware task factory on your event loop before creating tasks. Use `loop.set_task_factory(context.task_factory)` for a shared context, or `loop.set_task_factory(context.copying_task_factory)` to provide each new task with a fresh copy of the parent's context.","cause":"By default, context information stored with `aiotask-context` does not automatically propagate to new `asyncio.Task` objects spawned from a parent task unless a specific task factory is set.","error":"Context not propagating in child asyncio tasks"}]}