unsync

What it is and what it does

unsync is a decorator library that abstracts away the complexity of mixing async and synchronous code by automatically managing execution contexts. When you decorate an async function with @unsync, it runs in a background event loop managed by the library; when you decorate a regular function, it runs in a thread pool by default or a process pool if marked cpu_bound=True. All decorated functions return Unfuture objects—a hybrid future type that behaves like both asyncio.Future and concurrent.futures.Future, and can be awaited or blocked on with .result().

The library is useful when you have synchronous code that doesn't support asyncio (like blocking I/O libraries) but want to run it concurrently alongside async code, or when you want to avoid writing boilerplate event loop setup. It supports chaining operations with .then(), mixing sync and async functions in pipelines, and custom event loop policies like uvloop. The main tradeoff is that you lose explicit control over the event loop and thread/process management—the library handles it implicitly.

Use it for

• Run blocking I/O operations (file reads, network calls to non-async libraries) concurrently without rewriting them as async.
• Execute CPU-bound work in a separate process while keeping async code responsive in the main thread.
• Chain async and sync operations together using .then() without manually managing futures or callbacks.
• Simplify migration of synchronous codebases by decorating functions without restructuring control flow.
• Avoid event loop boilerplate when mixing asyncio with libraries that only support threading or multiprocessing.

Worth the install?

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Install

unsync on PyPI

Before you install

High install friction with no runtime dependencies. Package is dormant—last release was 2021-10-21, though the repository remains active with a recent commit on 2025-01-09. Maintenance status suggests the library is stable but not actively developed.

License in practice

MIT license is permissive, allowing commercial and private use with minimal restrictions. No licensing concerns for adoption.

Quickstart

from unsync import unsync
import asyncio

@unsync
async def my_async_task():
    await asyncio.sleep(1)
    return 'done'

result = my_async_task().result()  # Blocks until complete

Package facts

Evidence: unsync-1.4.0.tar.gz

Tags

More Application Frameworks packages

See also multitasking · synchronicity · threaded · futurist · duet · uvloop · txaio · Flask-Executor · requests-futures · nest-asyncio