from direct.task.Task import TaskManager, checkLeak, loop, print_exc_plus, sequence

This module defines a Python-level wrapper around the C++ AsyncTaskManager interface. It replaces the old full-Python implementation of the Task system.

For more information about the task system, consult the Tasks and Event Handling page in the programming manual.

Inheritance diagram

Inheritance diagram of direct.task.Task


Task aliases to panda3d.core.PythonTask for historical purposes.

class TaskManager[source]

Bases: object

MaxEpochSpeed = 0.03333333333333333
add(self, funcOrTask, name=None, sort=None, extraArgs=None, priority=None, uponDeath=None, appendTask=False, taskChain=None, owner=None, delay=None)[source]

Add a new task to the taskMgr. The task will begin executing immediately, or next frame if its sort value has already passed this frame.

  • funcOrTask – either an existing Task object (not already added to the task manager), or a callable function object. If this is a function, a new Task object will be created and returned. You may also pass in a coroutine object.

  • name (str) – the name to assign to the Task. Required, unless you are passing in a Task object that already has a name.

  • extraArgs (list) – the list of arguments to pass to the task function. If this is omitted, the list is just the task object itself.

  • appendTask (bool) – If this is true, then the task object itself will be appended to the end of the extraArgs list before calling the function.

  • sort (int) – the sort value to assign the task. The default sort is 0. Within a particular task chain, it is guaranteed that the tasks with a lower sort value will all run before tasks with a higher sort value run.

  • priority (int) – the priority at which to run the task. The default priority is 0. Higher priority tasks are run sooner, and/or more often. For historical purposes, if you specify a priority without also specifying a sort, the priority value is understood to actually be a sort value. (Previously, there was no priority value, only a sort value, and it was called “priority”.)

  • uponDeath (bool) – a function to call when the task terminates, either because it has run to completion, or because it has been explicitly removed.

  • taskChain (str) – the name of the task chain to assign the task to.

  • owner – an optional Python object that is declared as the “owner” of this task for maintenance purposes. The owner must have two methods: owner._addTask(self, task), which is called when the task begins, and owner._clearTask(self, task), which is called when the task terminates. This is all the ownermeans.

  • delay – an optional amount of seconds to wait before starting the task (equivalent to doMethodLater).


The new Task object that has been added, or the original Task object that was passed in.

property clock
doMethodLater(self, delayTime, funcOrTask, name, extraArgs=None, sort=None, priority=None, taskChain=None, uponDeath=None, appendTask=False, owner=None)[source]

Adds a task to be performed at some time in the future. This is identical to add(), except that the specified delayTime is applied to the Task object first, which means that the task will not begin executing until at least the indicated delayTime (in seconds) has elapsed.

After delayTime has elapsed, the task will become active, and will run in the soonest possible frame thereafter. If you wish to specify a task that will run in the next frame, use a delayTime of 0.

doYield(self, frameStartTime, nextScheduledTaskTime)[source]
extendedExceptions = 0
flushTaskProfiles(self, name=None)[source]

Returns list of all tasks, active and sleeping, in arbitrary order.


Returns the task currently executing on this thread, or None if this is being called outside of the task manager.


Returns list of all sleeping tasks in arbitrary order.

getProfileSession(self, name=None)[source]

Returns list of all active tasks in arbitrary order.

getTasksMatching(self, taskPattern)[source]

Returns a list of all tasks, active or sleeping, with a name that matches the pattern, which can include standard shell globbing characters like *, ?, and [].

getTasksNamed(self, taskName)[source]

Returns a list of all tasks, active or sleeping, with the indicated name.

hasTaskChain(self, chainName)[source]

Returns true if a task chain with the indicated name has already been defined, or false otherwise. Note that setupTaskChain() will implicitly define a task chain if it has not already been defined, or modify an existing one if it has, so in most cases there is no need to check this method first.

hasTaskNamed(self, taskName)[source]

Returns true if there is at least one task, active or sleeping, with the indicated name.

invokeDefaultHandler(self, signalNumber, stackFrame)[source]
keyboardInterruptHandler(self, signalNumber, stackFrame)[source]
logTaskProfiles(self, name=None)[source]
notify = <direct.directnotify.Notifier.Notifier object>
pStatsTasks = 0
profileFrames(self, num=None, session=None, callback=None)[source]
remove(self, taskOrName)[source]

Removes a task from the task manager. The task is stopped, almost as if it had returned task.done. (But if the task is currently executing, it will finish out its current frame before being removed.) You may specify either an explicit Task object, or the name of a task. If you specify a name, all tasks with the indicated name are removed. Returns the number of tasks removed.

removeTasksMatching(self, taskPattern)[source]

Removes all tasks whose names match the pattern, which can include standard shell globbing characters like *, ?, and []. See also remove().

Returns the number of tasks removed.

replaceMethod(self, oldMethod, newFunction)[source]

Starts the task manager running. Does not return until an exception is encountered (including KeyboardInterrupt).

setClock(self, clockObject)[source]
setProfileFrames(self, profileFrames)[source]
setProfileTasks(self, profileTasks)[source]
setupTaskChain(self, chainName, numThreads=None, tickClock=None, threadPriority=None, frameBudget=None, frameSync=None, timeslicePriority=None)[source]

Defines a new task chain. Each task chain executes tasks potentially in parallel with all of the other task chains (if numThreads is more than zero). When a new task is created, it may be associated with any of the task chains, by name (or you can move a task to another task chain with task.setTaskChain()). You can have any number of task chains, but each must have a unique name.

numThreads is the number of threads to allocate for this task chain. If it is 1 or more, then the tasks on this task chain will execute in parallel with the tasks on other task chains. If it is greater than 1, then the tasks on this task chain may execute in parallel with themselves (within tasks of the same sort value).

If tickClock is True, then this task chain will be responsible for ticking the global clock each frame (and thereby incrementing the frame counter). There should be just one task chain responsible for ticking the clock, and usually it is the default, unnamed task chain.

threadPriority specifies the priority level to assign to threads on this task chain. It may be one of TPLow, TPNormal, TPHigh, or TPUrgent. This is passed to the underlying threading system to control the way the threads are scheduled.

frameBudget is the maximum amount of time (in seconds) to allow this task chain to run per frame. Set it to -1 to mean no limit (the default). It’s not directly related to threadPriority.

frameSync is true to force the task chain to sync to the clock. When this flag is false, the default, the task chain will finish all of its tasks and then immediately start from the first task again, regardless of the clock frame. When it is true, the task chain will finish all of its tasks and then wait for the clock to tick to the next frame before resuming the first task. This only makes sense for threaded tasks chains; non-threaded task chains are automatically synchronous.

timeslicePriority is False in the default mode, in which each task runs exactly once each frame, round-robin style, regardless of the task’s priority value; or True to change the meaning of priority so that certain tasks are run less often, in proportion to their time used and to their priority value. See AsyncTaskManager.setTimeslicePriority() for more.


Invokes the task manager for one frame, and then returns. Normally, this executes each task exactly once, though task chains that are in sub-threads or that have frame budgets might execute their tasks differently.

taskTimerVerbose = 0

Creates a new future that returns done() when all of the contained futures are done.

Calling cancel() on the returned future will result in all contained futures that have not yet finished to be cancelled.


Print the usual traceback information, followed by a listing of all the local variables in each frame.