Files
ray/python/ray/tune/function_runner.py
T
Richard Liaw ea10cd212c [tune] add accessible trial_info (#7378)
* add accessible trial_info

* trial name and info

* doc

* fix
gp

* Update doc/source/tune-package-ref.rst

* Apply suggestions from code review

* fix

* trial

* fixtest

* testfix
2020-03-17 23:44:18 -07:00

294 lines
10 KiB
Python

import logging
import time
import inspect
import threading
import traceback
from six.moves import queue
from ray.tune import track
from ray.tune import TuneError
from ray.tune.trainable import Trainable
from ray.tune.result import TIME_THIS_ITER_S, RESULT_DUPLICATE
logger = logging.getLogger(__name__)
# Time between FunctionRunner checks when fetching
# new results after signaling the reporter to continue
RESULT_FETCH_TIMEOUT = 0.2
ERROR_REPORT_TIMEOUT = 10
ERROR_FETCH_TIMEOUT = 1
class StatusReporter:
"""Object passed into your function that you can report status through.
Example:
>>> def trainable_function(config, reporter):
>>> assert isinstance(reporter, StatusReporter)
>>> reporter(timesteps_this_iter=1)
"""
def __init__(self,
result_queue,
continue_semaphore,
trial_name=None,
trial_id=None,
logdir=None):
self._queue = result_queue
self._last_report_time = None
self._continue_semaphore = continue_semaphore
self._trial_name = trial_name
self._trial_id = trial_id
self._logdir = logdir
def __call__(self, **kwargs):
"""Report updated training status.
Pass in `done=True` when the training job is completed.
Args:
kwargs: Latest training result status.
Example:
>>> reporter(mean_accuracy=1, training_iteration=4)
>>> reporter(mean_accuracy=1, training_iteration=4, done=True)
Raises:
StopIteration: A StopIteration exception is raised if the trial has
been signaled to stop.
"""
assert self._last_report_time is not None, (
"StatusReporter._start() must be called before the first "
"report __call__ is made to ensure correct runtime metrics.")
# time per iteration is recorded directly in the reporter to ensure
# any delays in logging results aren't counted
report_time = time.time()
if TIME_THIS_ITER_S not in kwargs:
kwargs[TIME_THIS_ITER_S] = report_time - self._last_report_time
self._last_report_time = report_time
# add results to a thread-safe queue
self._queue.put(kwargs.copy(), block=True)
# This blocks until notification from the FunctionRunner that the last
# result has been returned to Tune and that the function is safe to
# resume training.
self._continue_semaphore.acquire()
def _start(self):
self._last_report_time = time.time()
@property
def logdir(self):
return self._logdir
@property
def trial_name(self):
"""Trial name for the corresponding trial of this Trainable."""
return self._trial_name
@property
def trial_id(self):
"""Trial id for the corresponding trial of this Trainable."""
return self._trial_id
class _RunnerThread(threading.Thread):
"""Supervisor thread that runs your script."""
def __init__(self, entrypoint, error_queue):
threading.Thread.__init__(self)
self._entrypoint = entrypoint
self._error_queue = error_queue
self.daemon = True
def run(self):
try:
self._entrypoint()
except StopIteration:
logger.debug(
("Thread runner raised StopIteration. Interperting it as a "
"signal to terminate the thread without error."))
except Exception as e:
logger.exception("Runner Thread raised error.")
try:
# report the error but avoid indefinite blocking which would
# prevent the exception from being propagated in the unlikely
# case that something went terribly wrong
err_tb_str = traceback.format_exc()
self._error_queue.put(
err_tb_str, block=True, timeout=ERROR_REPORT_TIMEOUT)
except queue.Full:
logger.critical(
("Runner Thread was unable to report error to main "
"function runner thread. This means a previous error "
"was not processed. This should never happen."))
raise e
class FunctionRunner(Trainable):
"""Trainable that runs a user function reporting results.
This mode of execution does not support checkpoint/restore."""
_name = "func"
def _setup(self, config):
# Semaphore for notifying the reporter to continue with the computation
# and to generate the next result.
self._continue_semaphore = threading.Semaphore(0)
# Queue for passing results between threads
self._results_queue = queue.Queue(1)
# Queue for passing errors back from the thread runner. The error queue
# has a max size of one to prevent stacking error and force error
# reporting to block until finished.
self._error_queue = queue.Queue(1)
self._status_reporter = StatusReporter(
self._results_queue,
self._continue_semaphore,
trial_name=self.trial_name,
trial_id=self.trial_id,
logdir=self.logdir)
self._last_result = {}
config = config.copy()
def entrypoint():
return self._trainable_func(config, self._status_reporter)
# the runner thread is not started until the first call to _train
self._runner = _RunnerThread(entrypoint, self._error_queue)
def _trainable_func(self):
"""Subclasses can override this to set the trainable func."""
raise NotImplementedError
def _train(self):
"""Implements train() for a Function API.
If the RunnerThread finishes without reporting "done",
Tune will automatically provide a magic keyword __duplicate__
along with a result with "done=True". The TrialRunner will handle the
result accordingly (see tune/trial_runner.py).
"""
if self._runner.is_alive():
# if started and alive, inform the reporter to continue and
# generate the next result
self._continue_semaphore.release()
else:
# if not alive, try to start
self._status_reporter._start()
try:
self._runner.start()
except RuntimeError:
# If this is reached, it means the thread was started and is
# now done or has raised an exception.
pass
result = None
while result is None and self._runner.is_alive():
# fetch the next produced result
try:
result = self._results_queue.get(
block=True, timeout=RESULT_FETCH_TIMEOUT)
except queue.Empty:
pass
# if no result were found, then the runner must no longer be alive
if result is None:
# Try one last time to fetch results in case results were reported
# in between the time of the last check and the termination of the
# thread runner.
try:
result = self._results_queue.get(block=False)
except queue.Empty:
pass
# check if error occured inside the thread runner
if result is None:
# only raise an error from the runner if all results are consumed
self._report_thread_runner_error(block=True)
# Under normal conditions, this code should never be reached since
# this branch should only be visited if the runner thread raised
# an exception. If no exception were raised, it means that the
# runner thread never reported any results which should not be
# possible when wrapping functions with `wrap_function`.
raise TuneError(
("Wrapped function ran until completion without reporting "
"results or raising an exception."))
else:
if not self._error_queue.empty():
logger.warning(
("Runner error waiting to be raised in main thread. "
"Logging all available results first."))
# This keyword appears if the train_func using the Function API
# finishes without "done=True". This duplicates the last result, but
# the TrialRunner will not log this result again.
if "__duplicate__" in result:
new_result = self._last_result.copy()
new_result.update(result)
result = new_result
self._last_result = result
return result
def _stop(self):
# If everything stayed in synch properly, this should never happen.
if not self._results_queue.empty():
logger.warning(
("Some results were added after the trial stop condition. "
"These results won't be logged."))
# Check for any errors that might have been missed.
self._report_thread_runner_error()
def _report_thread_runner_error(self, block=False):
try:
err_tb_str = self._error_queue.get(
block=block, timeout=ERROR_FETCH_TIMEOUT)
raise TuneError(("Trial raised an exception. Traceback:\n{}"
.format(err_tb_str)))
except queue.Empty:
pass
def wrap_function(train_func):
use_track = False
try:
func_args = inspect.getfullargspec(train_func).args
use_track = ("reporter" not in func_args and len(func_args) == 1)
if use_track:
logger.debug("tune.track signature detected.")
except Exception:
logger.info(
"Function inspection failed - assuming reporter signature.")
class WrappedFunc(FunctionRunner):
def _trainable_func(self, config, reporter):
output = train_func(config, reporter)
# If train_func returns, we need to notify the main event loop
# of the last result while avoiding double logging. This is done
# with the keyword RESULT_DUPLICATE -- see tune/trial_runner.py.
reporter(**{RESULT_DUPLICATE: True})
return output
class WrappedTrackFunc(FunctionRunner):
def _trainable_func(self, config, reporter):
track.init(_tune_reporter=reporter)
output = train_func(config)
reporter(**{RESULT_DUPLICATE: True})
track.shutdown()
return output
return WrappedTrackFunc if use_track else WrappedFunc