Release history¶

trio-parallel 1.0.0 (2021-12-04)¶

Fixed a hang on failed worker subprocess spawns that mostly occurred upon accidental multiprocessing recursive spawn. (#167)
Fixed a hang on Windows when trying to use WorkerContext.run_sync() in sequential and concurrent Trio runs. (#171)

With this release I consider the project “feature complete”.

Added an API to view statistics about a WorkerContext, specifically counting idle_workers and running_workers. (#155)

Opportunistically use cloudpickle to serialize jobs and results. (#115)
Timeout arguments of open_worker_context(), idle_timeout and grace_period, now work like trio timeouts, accepting any non-negative float value. (#116)
Worker process startup is now faster, by importing trio lazily (#117)
open_worker_context() now returns a context object that can be used to run functions explicitly in a certain context (WorkerContext.run_sync()) rather than implicitly altering the behavior of trio_parallel.run_sync(). (#127)

Added configuration options for the grace periods permitted to worker caches upon shutdown. This includes a new keyword argument for open_worker_context() and a new top level function atexit_shutdown_grace_period(). (#108)
open_worker_context() gained a new argument, init, and retire is no longer called before the first job in the worker. (#110)

The behavior and lifetime of worker processes can now be customized with the open_worker_context() context manager. (#19)

Remove __version__ attribute to avoid crash on import when metadata is not available (#55)

trio_parallel.BrokenWorkerError now contains a reference to the underlying worker process which can be inspected e.g. to handle specific exit codes. (#48)

Workers are now fully synchronized with only pipe/channel-like objects, making it impossible to leak semaphores. (#33)
Fix a regression of a rare race condition where idle workers shut down cleanly but appear broken. (#43)
Ensure a clean worker shutdown if IPC pipes are closed (#51)

Correctly handle the case where os.cpu_count returns None. (#32)
Ignore keyboard interrupt (SIGINT) in workers to ensure correct cancellation semantics and clean shutdown on CTRL+C. (#35)

Fixed an underlying race condition in IPC. Not a critical bugfix, as it should not be triggered in practice. (#15)
Reduce the production of zombie children on Unix systems (#20)
Close internal race condition when waiting for subprocess exit codes on macOS. (#23)
Avoid a race condition leading to deadlocks when a worker process is killed right after receiving work. (#25)

Changed subprocess context to explicitly always spawn new processes (#5)
Changed synchronization scheme to achieve full passing tests on
- Windows, Linux, MacOS
- CPython 3.6, 3.7, 3.8, 3.9
- Pypy 3.6, 3.7, 3.7-nightly
Note Pypy on Windows is not supported here or by Trio (#10)