twisted.python.threadpool.ThreadPool

class documentation

class ThreadPool: (source)

Constructor: ThreadPool(minthreads, maxthreads, name)

This class (hopefully) generalizes the functionality of a pool of threads to which work can be dispatched.

callInThread and stop should only be called from a single thread.

Method	`__getstate__`	Undocumented
Method	`__init__`	Create a new threadpool.
Method	`__setstate__`	Undocumented
Method	`adjustPoolsize`	Adjust the number of available threads by setting `min` and `max` to new values.
Method	`callInThread`	Call a callable object in a separate thread.
Method	`callInThreadWithCallback`	Call a callable object in a separate thread and call `onResult` with the return value, or a `twisted.python.failure.Failure` if the callable raises an exception.
Method	`dumpStats`	Dump some plain-text informational messages to the log about the state of this `ThreadPool`.
Method	`start`	Start the threadpool.
Method	`startAWorker`	Increase the number of available workers for the thread pool by 1, up to the maximum allowed by `ThreadPool.max`.
Method	`stop`	Shutdown the threads in the threadpool.
Method	`stopAWorker`	Decrease the number of available workers by 1, by quitting one as soon as it's idle.
Class Variable	`currentThread`	Undocumented
Instance Variable	`joined`	Undocumented
Instance Variable	`max`	Undocumented
Instance Variable	`min`	Undocumented
Instance Variable	`name`	Undocumented
Instance Variable	`started`	Whether or not the thread pool is currently running.
Instance Variable	`threads`	List of workers currently running in this thread pool.
Property	`waiters`	For legacy compatibility purposes, return the number of idle workers as expressed by a list the length of that number.
Property	`workers`	For legacy compatibility purposes, return a total number of workers.
Property	`working`	For legacy compatibility purposes, return the number of busy workers as expressed by a list the length of that number.
Method	`_generateName`	Generate a name for a new pool thread.
Instance Variable	`_pool`	A hook for testing.
Instance Variable	`_team`	Undocumented
Property	`_queue`	For legacy compatibility purposes, return an object with a `qsize` method that indicates the amount of work not yet allocated to a worker.

def __getstate__(self) -> _State: (source) ¶

Undocumented

def __init__(self, minthreads: int = 5, maxthreads: int = 20, name: str | None = None): (source) ¶

Create a new threadpool.

Parameters
minthreads:`int`	minimum number of threads in the pool
maxthreads:`int`	maximum number of threads in the pool
name:native `str`	The name to give this threadpool; visible in log messages.

def __setstate__(self, state: _State): (source) ¶

Undocumented

def adjustPoolsize(self, minthreads: int | None = None, maxthreads: int | None = None): (source) ¶

Adjust the number of available threads by setting min and max to new values.

Parameters
minthreads:`int \| None`	The new value for `ThreadPool.min`.
maxthreads:`int \| None`	The new value for `ThreadPool.max`.

def callInThread(self, func: Callable[_P, object], *args: _P.args, **kw: _P.kwargs): (source) ¶

Call a callable object in a separate thread.

Parameters
func:`Callable[_P, object]`	callable object to be called in separate thread
*args:`_P.args`	positional arguments to be passed to `func`
**kw:`_P.kwargs`	keyword args to be passed to `func`

def callInThreadWithCallback(self, onResult: Callable[[bool, _R], object] | None, func: Callable[_P, _R], *args: _P.args, **kw: _P.kwargs): (source) ¶

Call a callable object in a separate thread and call onResult with the return value, or a twisted.python.failure.Failure if the callable raises an exception.

The callable is allowed to block, but the onResult function must not block and should perform as little work as possible.

A typical action for onResult for a threadpool used with a Twisted reactor would be to schedule a twisted.internet.defer.Deferred to fire in the main reactor thread using .callFromThread. Note that onResult is called inside the separate thread, not inside the reactor thread.

Parameters
onResult:`Callable[[bool, _R], object] \| None`	a callable with the signature `(success, result)`. If the callable returns normally, `onResult` is called with `(True, result)` where `result` is the return value of the callable. If the callable throws an exception, `onResult` is called with `(False, failure)`. Optionally, `onResult` may be `None`, in which case it is not called at all.
func:`Callable[_P, _R]`	callable object to be called in separate thread
*args:`_P.args`	positional arguments to be passed to `func`
**kw:`_P.kwargs`	keyword arguments to be passed to `func`

def dumpStats(self): (source) ¶

Dump some plain-text informational messages to the log about the state of this ThreadPool.

def start(self): (source) ¶

Start the threadpool.

def startAWorker(self): (source) ¶

Increase the number of available workers for the thread pool by 1, up to the maximum allowed by ThreadPool.max.

def stop(self): (source) ¶

Shutdown the threads in the threadpool.

def stopAWorker(self): (source) ¶

Decrease the number of available workers by 1, by quitting one as soon as it's idle.

currentThread = (source) ¶

Undocumented

joined: bool = (source) ¶

Undocumented

max = (source) ¶

Undocumented

min = (source) ¶

Undocumented

name = (source) ¶

Undocumented

started: bool = (source) ¶

Whether or not the thread pool is currently running.

threads: list = (source) ¶

List of workers currently running in this thread pool.

@property
waiters: list of None = (source) ¶

For legacy compatibility purposes, return the number of idle workers as expressed by a list the length of that number.

@property
workers: int = (source) ¶

For legacy compatibility purposes, return a total number of workers.

@property
working: list of None = (source) ¶

For legacy compatibility purposes, return the number of busy workers as expressed by a list the length of that number.

def _generateName(self) -> str: (source) ¶

Generate a name for a new pool thread.

Returns
native `str`	A distinctive name for the thread.

_pool: callable compatible with _pool = (source) ¶

A hook for testing.

_team = (source) ¶

Undocumented

@property
_queue: _SupportsQsize = (source) ¶

For legacy compatibility purposes, return an object with a qsize method that indicates the amount of work not yet allocated to a worker.