Implement a first pass at actors in the API. (#242)

* Implement actor field for tasks

* Implement actor management in local scheduler.

* initial python frontend for actors

* import actors on worker

* IPython code completion and tests

* prepare creating actors through local schedulers

* add actor id to PyTask

* submit actor calls to local scheduler

* starting to integrate

* simple fix

* Fixes from rebasing.

* more work on python actors

* Improve local scheduler actor handlers.

* Pass actor ID to local scheduler when connecting a client.

* first working version of actors

* fixing actors

* fix creating two copies of the same actor

* fix actors

* remove sleep

* get rid of export synchronization

* update

* insert actor methods into the queue in the right order

* remove print statements

* make it compile again after rebase

* Minor updates.

* fix python actor ids

* Pass actor_id to start_worker.

* add test

* Minor changes.

* Update actor tests.

* Temporary plan for import counter.

* Temporarily fix import counters.

* Fix some tests.

* Fixes.

* Make actor creation non-blocking.

* Fix test?

* Fix actors on Python 2.

* fix rare case.

* Fix python 2 test.

* More tests.

* Small fixes.

* Linting.

* Revert tensorflow version to 0.12.0 temporarily.

* Small fix.

* Enhance inheritance test.

python/ray/workers/default_worker.py

@@ -6,6 +6,8 @@ import argparse
 import numpy as np
 import redis
 import traceback
+import sys
+import binascii
 
 import ray
 
@@ -15,6 +17,7 @@ parser.add_argument("--redis-address", required=True, type=str, help="the addres
 parser.add_argument("--object-store-name", required=True, type=str, help="the object store's name")
 parser.add_argument("--object-store-manager-name", required=True, type=str, help="the object store manager's name")
 parser.add_argument("--local-scheduler-name", required=True, type=str, help="the local scheduler's name")
+parser.add_argument("--actor-id", required=False, type=str, help="the actor ID of this worker")
 
 def random_string():
   return np.random.bytes(20)
@@ -26,7 +29,10 @@ if __name__ == "__main__":
           "store_socket_name": args.object_store_name,
           "manager_socket_name": args.object_store_manager_name,
           "local_scheduler_socket_name": args.local_scheduler_name}
-  ray.worker.connect(info, ray.WORKER_MODE)
+
+  actor_id = binascii.unhexlify(args.actor_id) if not args.actor_id is None else ray.worker.NIL_ACTOR_ID
+
+  ray.worker.connect(info, mode=ray.WORKER_MODE, actor_id=actor_id)
 
   error_explanation = """
 This error is unexpected and should not have happened. Somehow a worker crashed