ray/rllib/offline/input_reader.py
2019-11-16 10:02:58 -08:00

120 lines
4 KiB
Python

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import logging
import numpy as np
import threading
from ray.rllib.policy.sample_batch import MultiAgentBatch
from ray.rllib.utils.annotations import PublicAPI
from ray.rllib.utils import try_import_tf
tf = try_import_tf()
logger = logging.getLogger(__name__)
@PublicAPI
class InputReader(object):
"""Input object for loading experiences in policy evaluation."""
@PublicAPI
def next(self):
"""Return the next batch of experiences read.
Returns:
SampleBatch or MultiAgentBatch read.
"""
raise NotImplementedError
@PublicAPI
def tf_input_ops(self, queue_size=1):
"""Returns TensorFlow queue ops for reading inputs from this reader.
The main use of these ops is for integration into custom model losses.
For example, you can use tf_input_ops() to read from files of external
experiences to add an imitation learning loss to your model.
This method creates a queue runner thread that will call next() on this
reader repeatedly to feed the TensorFlow queue.
Arguments:
queue_size (int): Max elements to allow in the TF queue.
Example:
>>> class MyModel(rllib.model.Model):
... def custom_loss(self, policy_loss, loss_inputs):
... reader = JsonReader(...)
... input_ops = reader.tf_input_ops()
... logits, _ = self._build_layers_v2(
... {"obs": input_ops["obs"]},
... self.num_outputs, self.options)
... il_loss = imitation_loss(logits, input_ops["action"])
... return policy_loss + il_loss
You can find a runnable version of this in examples/custom_loss.py.
Returns:
dict of Tensors, one for each column of the read SampleBatch.
"""
if hasattr(self, "_queue_runner"):
raise ValueError(
"A queue runner already exists for this input reader. "
"You can only call tf_input_ops() once per reader.")
logger.info("Reading initial batch of data from input reader.")
batch = self.next()
if isinstance(batch, MultiAgentBatch):
raise NotImplementedError(
"tf_input_ops() is not implemented for multi agent batches")
keys = [
k for k in sorted(batch.keys())
if np.issubdtype(batch[k].dtype, np.number)
]
dtypes = [batch[k].dtype for k in keys]
shapes = {
k: (-1, ) + s[1:]
for (k, s) in [(k, batch[k].shape) for k in keys]
}
queue = tf.FIFOQueue(capacity=queue_size, dtypes=dtypes, names=keys)
tensors = queue.dequeue()
logger.info("Creating TF queue runner for {}".format(self))
self._queue_runner = _QueueRunner(self, queue, keys, dtypes)
self._queue_runner.enqueue(batch)
self._queue_runner.start()
out = {k: tf.reshape(t, shapes[k]) for k, t in tensors.items()}
return out
class _QueueRunner(threading.Thread):
"""Thread that feeds a TF queue from a InputReader."""
def __init__(self, input_reader, queue, keys, dtypes):
threading.Thread.__init__(self)
self.sess = tf.get_default_session()
self.daemon = True
self.input_reader = input_reader
self.keys = keys
self.queue = queue
self.placeholders = [tf.placeholder(dtype) for dtype in dtypes]
self.enqueue_op = queue.enqueue(dict(zip(keys, self.placeholders)))
def enqueue(self, batch):
data = {
self.placeholders[i]: batch[key]
for i, key in enumerate(self.keys)
}
self.sess.run(self.enqueue_op, feed_dict=data)
def run(self):
while True:
try:
batch = self.input_reader.next()
self.enqueue(batch)
except Exception:
logger.exception("Error reading from input")