twisted.python.threadpool.ThreadPool

Known subclasses: twisted.internet.test.test_resolver.DeterministicThreadPool, twisted.test.test_threadpool.MemoryPool

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.

Instance Variable	started	Whether or not the thread pool is currently running. (type: `bool`)
Instance Variable	threads	List of workers currently running in this thread pool. (type: `list`)
Method	__init__	Create a new threadpool.
Method	workers	For legacy compatibility purposes, return a total number of workers.
Method	working	For legacy compatibility purposes, return the number of busy workers as expressed by a list the length of that number.
Method	waiters	For legacy compatibility purposes, return the number of idle workers as expressed by a list the length of that number.
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	stopAWorker	Decrease the number of available workers by 1, by quitting one as soon as it's idle.
Method	__setstate__	Undocumented
Method	__getstate__	Undocumented
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	stop	Shutdown the threads in the threadpool.
Method	adjustPoolsize	Adjust the number of available threads by setting `min` and `max` to new values.
Method	dumpStats	Dump some plain-text informational messages to the log about the state of this `ThreadPool`.
Instance Variable	_pool	A hook for testing. (type: callable compatible with `_pool`)
Method	_queue	For legacy compatibility purposes, return an object with a `qsize` method that indicates the amount of work not yet allocated to a worker.
Method	_generateName	Generate a name for a new pool thread.

started =

Whether or not the thread pool is currently running. (type: bool)

threads =

List of workers currently running in this thread pool. (type: list)

_pool =

A hook for testing. (type: callable compatible with _pool)

def __init__(self, minthreads=5, maxthreads=20, name=None):

overridden in twisted.internet.test.test_resolver.DeterministicThreadPool, twisted.test.test_threadpool.MemoryPool

Create a new threadpool.

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

@property
def workers(self):

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

Returns the current number of workers, both idle and busy (but not those that have been quit by ThreadPool.adjustPoolsize) (type: int)

@property
def working(self):

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

Returns the number of workers currently processing a work item. (type: list of None)

@property
def waiters(self):

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

Returns the number of workers currently alive (with an allocated thread) but waiting for new work. (type: list of None)

@property
def _queue(self):

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

Returns an object with a qsize method.

def start(self):

Start the threadpool.

def startAWorker(self):

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

def _generateName(self):

Generate a name for a new pool thread.

Returns A distinctive name for the thread. (type: native str)

def stopAWorker(self):

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

def __setstate__(self, state):

Undocumented

def __getstate__(self):

Undocumented

def callInThread(self, func, *args, **kw):

Call a callable object in a separate thread.

Parameters	func	callable object to be called in separate thread
	args	positional arguments to be passed to `func`
	kw	keyword args to be passed to `func`

def callInThreadWithCallback(self, onResult, func, *args, **kw):

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	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 object to be called in separate thread
	args	positional arguments to be passed to `func`
	kw	keyword arguments to be passed to `func`

def stop(self):

Shutdown the threads in the threadpool.

def adjustPoolsize(self, minthreads=None, maxthreads=None):

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

Parameters	minthreads	The new value for `ThreadPool.min`.
	maxthreads	The new value for `ThreadPool.max`.

def dumpStats(self):

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

API Documentation for twisted, generated by pydoctor at 2020-03-25 17:34:30.

twisted.python.threadpool.ThreadPool class documentation

`twisted.python.threadpool.ThreadPool` class documentation