def __init__(self,
scheduler,
storage,
cache=None,
pool_size=None,
debug=True):
"""
:param scheduler: The local scheduler for creating execution graphs.
:type scheduler: :class:`pants.engine.exp.scheduler.LocalScheduler`
:param storage: The storage instance for serializables keyed by their hashes.
:type storage: :class:`pants.engine.exp.storage.Storage`
:param cache: The cache instance for storing execution results, by default it uses the same
Storage instance if not specified.
:type cache: :class:`pants.engine.exp.storage.Cache`
:param int pool_size: The number of worker processes to use; by default 2 processes per core will
be used.
:param bool debug: `True` to turn on pickling error debug mode (slower); True by default.
"""
super(LocalMultiprocessEngine, self).__init__(scheduler, storage,
cache)
self._pool_size = pool_size if pool_size and pool_size > 0 else 2 * multiprocessing.cpu_count(
)
execute_step = functools.partial(_execute_step, self._maybe_cache_put,
debug)
node_builder = scheduler.node_builder()
process_initializer = functools.partial(_process_initializer,
node_builder, self._storage)
self._pool = StatefulPool(self._pool_size, process_initializer,
execute_step)
self._debug = debug
