19.5. asyncio
— Asynchronous I/O, event loop, coroutines and tasks¶
3.4 版新加入.
Source code: Lib/asyncio/
This module provides infrastructure for writing single-threaded concurrent code using coroutines, multiplexing I/O access over sockets and other resources, running network clients and servers, and other related primitives. Here is a more detailed list of the package contents:
- a pluggable event loop with various system-specific implementations;
- transport and protocol abstractions (similar to those in Twisted);
- concrete support for TCP, UDP, SSL, subprocess pipes, delayed calls, and others (some may be system-dependent);
- a
Future
class that mimics the one in theconcurrent.futures
module, but adapted for use with the event loop; - coroutines and tasks based on
yield from
(PEP 380), to help write concurrent code in a sequential fashion; - cancellation support for
Future
s and coroutines; - synchronization primitives for use between coroutines in
a single thread, mimicking those in the
threading
module; - an interface for passing work off to a threadpool, for times when you absolutely, positively have to use a library that makes blocking I/O calls.
Asynchronous programming is more complex than classical 「sequential」 programming: see the Develop with asyncio page which lists common traps and explains how to avoid them. Enable the debug mode during development to detect common issues.
Table of contents:
- 19.5.1. Base Event Loop
- 19.5.1.1. Run an event loop
- 19.5.1.2. Calls
- 19.5.1.3. Delayed calls
- 19.5.1.4. Futures
- 19.5.1.5. Tasks
- 19.5.1.6. Creating connections
- 19.5.1.7. Creating listening connections
- 19.5.1.8. File Transferring
- 19.5.1.9. TLS Upgrade
- 19.5.1.10. Watch file descriptors
- 19.5.1.11. Low-level socket operations
- 19.5.1.12. Resolve host name
- 19.5.1.13. Connect pipes
- 19.5.1.14. UNIX signals
- 19.5.1.15. Executor
- 19.5.1.16. Error Handling API
- 19.5.1.17. Debug mode
- 19.5.1.18. Server
- 19.5.1.19. Handle
- 19.5.1.20. SendfileNotAvailableError
- 19.5.1.21. Event loop examples
- 19.5.2. Event loops
- 19.5.3. Tasks and coroutines
- 19.5.4. Transports and protocols (callback based API)
- 19.5.5. Streams (coroutine based API)
- 19.5.6. 子程序
- 19.5.7. Synchronization primitives
- 19.5.8. Queues
- 19.5.9. Develop with asyncio
- 19.5.9.1. Debug mode of asyncio
- 19.5.9.2. Cancellation
- 19.5.9.3. Concurrency and multithreading
- 19.5.9.4. Handle blocking functions correctly
- 19.5.9.5. Logging
- 19.5.9.6. Detect coroutine objects never scheduled
- 19.5.9.7. Detect exceptions never consumed
- 19.5.9.8. Chain coroutines correctly
- 19.5.9.9. Pending task destroyed
- 19.5.9.10. Close transports and event loops