Datastructures - celery.datastructures¶

Custom Datastructures

class celery.datastructures.ExceptionInfo(exc_info)¶

Exception wrapping an exception and its traceback.

Parameter:	exc_info – The exception tuple info as returned by traceback.format_exception().

exception¶

The original exception.

traceback¶

A traceback from the point when exception was raised.

class celery.datastructures.PositionQueue(length)¶

A positional queue of a specific length, with slots that are either filled or unfilled. When all of the positions are filled, the queue is considered full().

Parameter:	length – see length.

length¶

The number of items required for the queue to be considered full.

class UnfilledPosition(position)¶

Describes an unfilled slot.

PositionQueue.filled¶

Returns the filled slots as a list.

PositionQueue.full()¶

Returns True if all of the slots has been filled.

class celery.datastructures.SharedCounter(initial_value)¶

An integer that can be updated by several threads at once.

Please note that the final value is not synchronized, this means that you should not update the value by using a previous value, the only reliable operations are increment and decrement.

Example

>>> max_clients = SharedCounter(initial_value=10)

# Thread one >>> max_clients += 1 # OK (safe)

# Thread two >>> max_clients -= 3 # OK (safe)

# Main thread >>> if client >= int(max_clients): # Max clients now at 8 ... wait()

>>> max_client = max_clients + 10 # NOT OK (unsafe)

decrement(n=1)¶

Decrement value.

increment(n=1)¶

Increment value.