dragon.mpbridge.queues.DragonQueue

class DragonQueue

Bases: PatchedDragonNativeQueue

A queue co-located on the same node by default as the creating process

__init__(*args, ctx=None, **kwargs)

Init method

Parameters:

• maxsize (int , optional) – sets the upperbound limit on the number of items that can be placed in the queue, defaults to 100

• m_uid (int , optional) – The m_uid of the memory pool to use, defaults to _DEF_MUID

• block_size (int , optional) – Block size for the underlying channel, defaults to 64 kbytes

• joinable (bool , optional) – If this queue should be joinable, defaults to False

• policy (object , optional) – policy object, defaults to POLICY_USER

• _ext_channel (instance of dragon.channel, optional) – non-local externally managed channel for testing purposes only, defaults to None

Raises:

• QueueError – If something goes wrong during creation

• ValueError – If a parameter is wrong

• NotImplementedError – If a joinable queue is used with an external channel

Methods

__init__(*args[, ctx])	Init method
cancel_join_thread()	This method is a no-op for Dragon based multiprocessing and exists solely for compatibility with the queues.Queue API.
close()	Indicate that no more data will be put on this queue by the current process.
empty()	Return True if the queue is empty, False otherwise.
full()	Return True if the queue is full, False otherwise.
get([block, timeout])	Remove and return an item from the queue.
get_nowait()	Equivalent to get(False).
join_thread()	This method is a no-op for Dragon based multiprocessing and exists solely for compatibility with the queues.Queue API.
put(obj[, block, timeout])	Puts the serialization of an object onto the queue.
put_nowait(obj)	Equivalent to put(obj, False).
qsize()	Return the approximate size of the queue.

__init__(*args, ctx=None, **kwargs)

Init method

Parameters:

• maxsize (int , optional) – sets the upperbound limit on the number of items that can be placed in the queue, defaults to 100

• m_uid (int , optional) – The m_uid of the memory pool to use, defaults to _DEF_MUID

• block_size (int , optional) – Block size for the underlying channel, defaults to 64 kbytes

• joinable (bool , optional) – If this queue should be joinable, defaults to False

• policy (object , optional) – policy object, defaults to POLICY_USER

• _ext_channel (instance of dragon.channel, optional) – non-local externally managed channel for testing purposes only, defaults to None

Raises:

• QueueError – If something goes wrong during creation

• ValueError – If a parameter is wrong

• NotImplementedError – If a joinable queue is used with an external channel

cancel_join_thread()

This method is a no-op for Dragon based multiprocessing and exists solely for compatibility with the queues.Queue API.

close() → None

Indicate that no more data will be put on this queue by the current process. The refcount of the background channel will be released and the channel might be removed, if no other processes are holding it. This version includes a patch for the multiprocessing unit tests.

empty() → bool

Return True if the queue is empty, False otherwise. This might not be reliable

Raises:

ValueError – If the queue is closed

Returns:

Wether or not the queue is empty

Return type:

bool

full() → bool

Return True if the queue is full, False otherwise.

Raises:

ValueError – If the queue is closed

Returns:

Wether or not the queue is full

Return type:

bool

get(block: bool = True, timeout: float = None) → object

Remove and return an item from the queue.

Parameters:

• block (bool , optional) – Make this call blocking, defaults to True

• timeout (float , optional) – number of seconds to block, defaults to None

Raises:

• ValueError – If queue is closed

• queue.Empty – If queue is empty

Returns:

The next item in the queue

Return type:

object

get_nowait() → object

Equivalent to get(False).

Returns:

The next item in the queue

Return type:

object

join_thread() → None

This method is a no-op for Dragon based multiprocessing and exists solely for compatibility with the queues.Queue API.

put(obj, block=True, timeout=None) → None

Puts the serialization of an object onto the queue. This version includes patches for the multiprocessing unit tests

Parameters:

• obj – object to serialize and put

• block – Whether to block

• timeout – Timeout, if blocking. None means infinity, default

Returns:

None

put_nowait(obj) → None

Equivalent to put(obj, False).

Parameters:

obj (object ) – object to serialize and put

Returns:

None

qsize() → int

Return the approximate size of the queue. This number may not be reliable.

Raises:

ValueError – If the queue is closed

Returns:

approximate number of items in the queue

Return type:

int