Python Trio Library
Trio is a modern library for asynchronous concurrency in Python. It is designed to be easier to use and harder to make mistakes with than asyncio, focusing on "structured concurrency".
Installation
pip install trioBasic Usage
Trio uses async/await syntax but requires a trio.run() entry point.
import trio
async def main():
print("Hello")
await trio.sleep(1)
print("World")
trio.run(main)Nurseries (Structured Concurrency)
In Trio, you spawn tasks inside a "nursery". The nursery block doesn't exit until all tasks inside it have completed.
import trio
async def child1():
print("Child 1 started")
await trio.sleep(1)
print("Child 1 finished")
async def child2():
print("Child 2 started")
await trio.sleep(0.5)
print("Child 2 finished")
async def main():
async with trio.open_nursery() as nursery:
nursery.start_soon(child1)
nursery.start_soon(child2)
print("All children finished")
trio.run(main)Timeouts
Trio makes timeouts easy and safe with context managers.
import trio
async def main():
with trio.move_on_after(2):
await trio.sleep(5)
print("This won't print")
print("Timeout expired, continuing...")
trio.run(main)Cancellation
Cancellation is handled via "cancel scopes".
import trio
async def main():
with trio.CancelScope() as scope:
scope.cancel()
await trio.sleep(1)
print("This won't print")
trio.run(main)