| | from __future__ import print_function, division, absolute_import |
| |
|
| | import asyncio |
| | import concurrent.futures |
| | import contextlib |
| |
|
| | import time |
| | from uuid import uuid4 |
| | import weakref |
| |
|
| | from .parallel import parallel_config |
| | from .parallel import AutoBatchingMixin, ParallelBackendBase |
| |
|
| | from ._utils import ( |
| | _TracebackCapturingWrapper, |
| | _retrieve_traceback_capturing_wrapped_call |
| | ) |
| |
|
| | try: |
| | import dask |
| | import distributed |
| | except ImportError: |
| | dask = None |
| | distributed = None |
| |
|
| | if dask is not None and distributed is not None: |
| | from dask.utils import funcname |
| | from dask.sizeof import sizeof |
| | from dask.distributed import ( |
| | Client, |
| | as_completed, |
| | get_client, |
| | secede, |
| | rejoin, |
| | ) |
| | from distributed.utils import thread_state |
| |
|
| | try: |
| | |
| | |
| | from distributed.utils import TimeoutError as _TimeoutError |
| | except ImportError: |
| | from tornado.gen import TimeoutError as _TimeoutError |
| |
|
| |
|
| | def is_weakrefable(obj): |
| | try: |
| | weakref.ref(obj) |
| | return True |
| | except TypeError: |
| | return False |
| |
|
| |
|
| | class _WeakKeyDictionary: |
| | """A variant of weakref.WeakKeyDictionary for unhashable objects. |
| | |
| | This datastructure is used to store futures for broadcasted data objects |
| | such as large numpy arrays or pandas dataframes that are not hashable and |
| | therefore cannot be used as keys of traditional python dicts. |
| | |
| | Furthermore using a dict with id(array) as key is not safe because the |
| | Python is likely to reuse id of recently collected arrays. |
| | """ |
| |
|
| | def __init__(self): |
| | self._data = {} |
| |
|
| | def __getitem__(self, obj): |
| | ref, val = self._data[id(obj)] |
| | if ref() is not obj: |
| | |
| | raise KeyError(obj) |
| | return val |
| |
|
| | def __setitem__(self, obj, value): |
| | key = id(obj) |
| | try: |
| | ref, _ = self._data[key] |
| | if ref() is not obj: |
| | |
| | raise KeyError(obj) |
| | except KeyError: |
| | |
| | |
| | |
| | def on_destroy(_): |
| | del self._data[key] |
| | ref = weakref.ref(obj, on_destroy) |
| | self._data[key] = ref, value |
| |
|
| | def __len__(self): |
| | return len(self._data) |
| |
|
| | def clear(self): |
| | self._data.clear() |
| |
|
| |
|
| | def _funcname(x): |
| | try: |
| | if isinstance(x, list): |
| | x = x[0][0] |
| | except Exception: |
| | pass |
| | return funcname(x) |
| |
|
| |
|
| | def _make_tasks_summary(tasks): |
| | """Summarize of list of (func, args, kwargs) function calls""" |
| | unique_funcs = {func for func, args, kwargs in tasks} |
| |
|
| | if len(unique_funcs) == 1: |
| | mixed = False |
| | else: |
| | mixed = True |
| | return len(tasks), mixed, _funcname(tasks) |
| |
|
| |
|
| | class Batch: |
| | """dask-compatible wrapper that executes a batch of tasks""" |
| | def __init__(self, tasks): |
| | |
| | |
| | self._num_tasks, self._mixed, self._funcname = _make_tasks_summary( |
| | tasks |
| | ) |
| |
|
| | def __call__(self, tasks=None): |
| | results = [] |
| | with parallel_config(backend='dask'): |
| | for func, args, kwargs in tasks: |
| | results.append(func(*args, **kwargs)) |
| | return results |
| |
|
| | def __repr__(self): |
| | descr = f"batch_of_{self._funcname}_{self._num_tasks}_calls" |
| | if self._mixed: |
| | descr = "mixed_" + descr |
| | return descr |
| |
|
| |
|
| | def _joblib_probe_task(): |
| | |
| | pass |
| |
|
| |
|
| | class DaskDistributedBackend(AutoBatchingMixin, ParallelBackendBase): |
| | MIN_IDEAL_BATCH_DURATION = 0.2 |
| | MAX_IDEAL_BATCH_DURATION = 1.0 |
| | supports_retrieve_callback = True |
| | default_n_jobs = -1 |
| |
|
| | def __init__(self, scheduler_host=None, scatter=None, |
| | client=None, loop=None, wait_for_workers_timeout=10, |
| | **submit_kwargs): |
| | super().__init__() |
| |
|
| | if distributed is None: |
| | msg = ("You are trying to use 'dask' as a joblib parallel backend " |
| | "but dask is not installed. Please install dask " |
| | "to fix this error.") |
| | raise ValueError(msg) |
| |
|
| | if client is None: |
| | if scheduler_host: |
| | client = Client(scheduler_host, loop=loop, |
| | set_as_default=False) |
| | else: |
| | try: |
| | client = get_client() |
| | except ValueError as e: |
| | msg = ("To use Joblib with Dask first create a Dask Client" |
| | "\n\n" |
| | " from dask.distributed import Client\n" |
| | " client = Client()\n" |
| | "or\n" |
| | " client = Client('scheduler-address:8786')") |
| | raise ValueError(msg) from e |
| |
|
| | self.client = client |
| |
|
| | if scatter is not None and not isinstance(scatter, (list, tuple)): |
| | raise TypeError("scatter must be a list/tuple, got " |
| | "`%s`" % type(scatter).__name__) |
| |
|
| | if scatter is not None and len(scatter) > 0: |
| | |
| | self._scatter = list(scatter) |
| | scattered = self.client.scatter(scatter, broadcast=True) |
| | self.data_futures = {id(x): f for x, f in zip(scatter, scattered)} |
| | else: |
| | self._scatter = [] |
| | self.data_futures = {} |
| | self.wait_for_workers_timeout = wait_for_workers_timeout |
| | self.submit_kwargs = submit_kwargs |
| | self.waiting_futures = as_completed( |
| | [], |
| | loop=client.loop, |
| | with_results=True, |
| | raise_errors=False |
| | ) |
| | self._results = {} |
| | self._callbacks = {} |
| |
|
| | async def _collect(self): |
| | while self._continue: |
| | async for future, result in self.waiting_futures: |
| | cf_future = self._results.pop(future) |
| | callback = self._callbacks.pop(future) |
| | if future.status == "error": |
| | typ, exc, tb = result |
| | cf_future.set_exception(exc) |
| | else: |
| | cf_future.set_result(result) |
| | callback(result) |
| | await asyncio.sleep(0.01) |
| |
|
| | def __reduce__(self): |
| | return (DaskDistributedBackend, ()) |
| |
|
| | def get_nested_backend(self): |
| | return DaskDistributedBackend(client=self.client), -1 |
| |
|
| | def configure(self, n_jobs=1, parallel=None, **backend_args): |
| | self.parallel = parallel |
| | return self.effective_n_jobs(n_jobs) |
| |
|
| | def start_call(self): |
| | self._continue = True |
| | self.client.loop.add_callback(self._collect) |
| | self.call_data_futures = _WeakKeyDictionary() |
| |
|
| | def stop_call(self): |
| | |
| | |
| | self._continue = False |
| | |
| | |
| | |
| | time.sleep(0.01) |
| | self.call_data_futures.clear() |
| |
|
| | def effective_n_jobs(self, n_jobs): |
| | effective_n_jobs = sum(self.client.ncores().values()) |
| | if effective_n_jobs != 0 or not self.wait_for_workers_timeout: |
| | return effective_n_jobs |
| |
|
| | |
| | |
| | |
| | try: |
| | self.client.submit(_joblib_probe_task).result( |
| | timeout=self.wait_for_workers_timeout |
| | ) |
| | except _TimeoutError as e: |
| | error_msg = ( |
| | "DaskDistributedBackend has no worker after {} seconds. " |
| | "Make sure that workers are started and can properly connect " |
| | "to the scheduler and increase the joblib/dask connection " |
| | "timeout with:\n\n" |
| | "parallel_config(backend='dask', wait_for_workers_timeout={})" |
| | ).format(self.wait_for_workers_timeout, |
| | max(10, 2 * self.wait_for_workers_timeout)) |
| | raise TimeoutError(error_msg) from e |
| | return sum(self.client.ncores().values()) |
| |
|
| | async def _to_func_args(self, func): |
| | itemgetters = dict() |
| |
|
| | |
| | |
| | call_data_futures = getattr(self, 'call_data_futures', None) |
| |
|
| | async def maybe_to_futures(args): |
| | out = [] |
| | for arg in args: |
| | arg_id = id(arg) |
| | if arg_id in itemgetters: |
| | out.append(itemgetters[arg_id]) |
| | continue |
| |
|
| | f = self.data_futures.get(arg_id, None) |
| | if f is None and call_data_futures is not None: |
| | try: |
| | f = await call_data_futures[arg] |
| | except KeyError: |
| | pass |
| | if f is None: |
| | if is_weakrefable(arg) and sizeof(arg) > 1e3: |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | _coro = self.client.scatter( |
| | arg, |
| | asynchronous=True, |
| | hash=False |
| | ) |
| | |
| | |
| | |
| | |
| | t = asyncio.Task(_coro) |
| | call_data_futures[arg] = t |
| |
|
| | f = await t |
| |
|
| | if f is not None: |
| | out.append(f) |
| | else: |
| | out.append(arg) |
| | return out |
| |
|
| | tasks = [] |
| | for f, args, kwargs in func.items: |
| | args = list(await maybe_to_futures(args)) |
| | kwargs = dict(zip(kwargs.keys(), |
| | await maybe_to_futures(kwargs.values()))) |
| | tasks.append((f, args, kwargs)) |
| |
|
| | return (Batch(tasks), tasks) |
| |
|
| | def apply_async(self, func, callback=None): |
| |
|
| | cf_future = concurrent.futures.Future() |
| | cf_future.get = cf_future.result |
| |
|
| | async def f(func, callback): |
| | batch, tasks = await self._to_func_args(func) |
| | key = f'{repr(batch)}-{uuid4().hex}' |
| |
|
| | dask_future = self.client.submit( |
| | _TracebackCapturingWrapper(batch), |
| | tasks=tasks, |
| | key=key, |
| | **self.submit_kwargs |
| | ) |
| | self.waiting_futures.add(dask_future) |
| | self._callbacks[dask_future] = callback |
| | self._results[dask_future] = cf_future |
| |
|
| | self.client.loop.add_callback(f, func, callback) |
| |
|
| | return cf_future |
| |
|
| | def retrieve_result_callback(self, out): |
| | return _retrieve_traceback_capturing_wrapped_call(out) |
| |
|
| | def abort_everything(self, ensure_ready=True): |
| | """ Tell the client to cancel any task submitted via this instance |
| | |
| | joblib.Parallel will never access those results |
| | """ |
| | with self.waiting_futures.lock: |
| | self.waiting_futures.futures.clear() |
| | while not self.waiting_futures.queue.empty(): |
| | self.waiting_futures.queue.get() |
| |
|
| | @contextlib.contextmanager |
| | def retrieval_context(self): |
| | """Override ParallelBackendBase.retrieval_context to avoid deadlocks. |
| | |
| | This removes thread from the worker's thread pool (using 'secede'). |
| | Seceding avoids deadlock in nested parallelism settings. |
| | """ |
| | |
| | |
| | if hasattr(thread_state, 'execution_state'): |
| | |
| | secede() |
| |
|
| | yield |
| |
|
| | if hasattr(thread_state, 'execution_state'): |
| | rejoin() |
| |
|