Remove some Python 2 compatibility code. (#6624)

python/ray/experimental/serve/__init__.py

@@ -1,12 +1,9 @@
-import sys
 from ray.experimental.serve.backend_config import BackendConfig
 from ray.experimental.serve.policy import RoutePolicy
-if sys.version_info < (3, 0):
-    raise ImportError("serve is Python 3 only.")
-
 from ray.experimental.serve.api import (
     init, create_backend, create_endpoint, link, split, get_handle, stat,
     set_backend_config, get_backend_config, accept_batch)  # noqa: E402
+
 __all__ = [
     "init", "create_backend", "create_endpoint", "link", "split", "get_handle",
     "stat", "set_backend_config", "get_backend_config", "BackendConfig",

python/ray/experimental/sgd/tests/test_pytorch_runner.py

@@ -3,18 +3,13 @@ from __future__ import division
 from __future__ import print_function
 
 import numpy as np
-import sys
 import torch
 import torch.nn as nn
 import unittest
+from unittest.mock import MagicMock
 
 from ray.experimental.sgd.pytorch.pytorch_runner import PyTorchRunner
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import MagicMock
-else:
-    from mock import MagicMock
-
 
 class LinearDataset(torch.utils.data.Dataset):
     """y = a * x + b"""

python/ray/function_manager.py

@@ -326,17 +326,14 @@ class FunctionActorManager(object):
                 unnecessarily or fail to give warnings, but the application's
                 behavior won't change.
         """
-        if sys.version_info[0] >= 3:
-            import io
-            string_file = io.StringIO()
-            if sys.version_info[1] >= 7:
-                dis.dis(function_or_class, file=string_file, depth=2)
-            else:
-                dis.dis(function_or_class, file=string_file)
-            collision_identifier = (
-                function_or_class.__name__ + ":" + string_file.getvalue())
+        import io
+        string_file = io.StringIO()
+        if sys.version_info[1] >= 7:
+            dis.dis(function_or_class, file=string_file, depth=2)
         else:
-            collision_identifier = function_or_class.__name__
+            dis.dis(function_or_class, file=string_file)
+        collision_identifier = (
+            function_or_class.__name__ + ":" + string_file.getvalue())
 
         # Return a hash of the identifier in case it is too large.
         return hashlib.sha1(collision_identifier.encode("ascii")).digest()

python/ray/node.py

@@ -27,7 +27,6 @@ from ray.utils import try_to_create_directory, try_to_symlink
 # using logging.basicConfig in its entry/init points.
 logger = logging.getLogger(__name__)
 
-PY3 = sys.version_info.major >= 3
 SESSION_LATEST = "session_latest"
 
 
@@ -599,12 +598,10 @@ class Node(object):
         self.start_redis()
         self.start_monitor()
         self.start_raylet_monitor()
-        # The dashboard is Python3.x only.
-        if PY3:
-            if self._ray_params.include_webui:
-                self.start_dashboard(require_webui=True)
-            elif self._ray_params.include_webui is None:
-                self.start_dashboard(require_webui=False)
+        if self._ray_params.include_webui:
+            self.start_dashboard(require_webui=True)
+        elif self._ray_params.include_webui is None:
+            self.start_dashboard(require_webui=False)
 
     def start_ray_processes(self):
         """Start all of the processes on the node."""
@@ -614,8 +611,7 @@ class Node(object):
 
         self.start_plasma_store()
         self.start_raylet()
-        if PY3:
-            self.start_reporter()
+        self.start_reporter()
 
         if self._ray_params.include_log_monitor:
             self.start_log_monitor()
@@ -755,10 +751,8 @@ class Node(object):
             check_alive (bool): Raise an exception if the process was already
                 dead.
         """
-        # reporter is started only in PY3.
-        if PY3:
-            self._kill_process_type(
-                ray_constants.PROCESS_TYPE_REPORTER, check_alive=check_alive)
+        self._kill_process_type(
+            ray_constants.PROCESS_TYPE_REPORTER, check_alive=check_alive)
 
     def kill_dashboard(self, check_alive=True):
         """Kill the dashboard.

python/ray/services.py

@@ -446,9 +446,7 @@ def start_ray_process(command,
     # in interactive sessions. This is only supported in Python 3.3 and above.
     def block_sigint():
         import signal
-        import sys
-        if sys.version_info >= (3, 3):
-            signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGINT})
+        signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGINT})
 
     process = subprocess.Popen(
         command,
@@ -1068,9 +1066,6 @@ def start_dashboard(require_webui,
     if redis_password:
         command += ["--redis-password", redis_password]
 
-    if sys.version_info <= (3, 0):
-        return None, None
-
     webui_dependencies_present = True
     try:
         import aiohttp  # noqa: F401

python/ray/tests/test_actor.py

@@ -38,16 +38,6 @@ def test_actor_init_error_propagated(ray_start_regular):
         ray.get(actor.foo.remote())
 
 
-@pytest.mark.skipif(
-    sys.version_info >= (3, 0), reason="This test requires Python 2.")
-def test_old_style_error(ray_start_regular):
-    with pytest.raises(TypeError):
-
-        @ray.remote
-        class Actor:
-            pass
-
-
 def test_keyword_args(ray_start_regular):
     @ray.remote
     class Actor(object):
@@ -189,8 +179,6 @@ def test_custom_classes(ray_start_regular):
     assert results2[2].x == 3
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 def test_actor_class_attributes(ray_start_regular):
     class Grandparent(object):
         GRANDPARENT = 2
@@ -423,8 +411,6 @@ def test_actor_deletion(ray_start_regular):
     [ray.test_utils.wait_for_pid_to_exit(pid) for pid in pids]
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 def test_actor_method_deletion(ray_start_regular):
     @ray.remote
     class Actor(object):
@@ -1497,5 +1483,4 @@ def test_actor_creation_task_crash(ray_start_regular):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tests/test_actor_resources.py

@@ -403,8 +403,6 @@ def test_actor_multiple_gpus_from_multiple_tasks(ray_start_cluster):
     assert ready_ids == []
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 def test_actors_and_tasks_with_gpus(ray_start_cluster):
     cluster = ray_start_cluster
     num_nodes = 3
@@ -638,9 +636,6 @@ def test_blocking_actor_task(shutdown_only):
     assert remaining_ids == [x_id]
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0),
-    reason="This test is currently failing on Python 2.7.")
 def test_lifetime_and_transient_resources(ray_start_regular):
     # This actor acquires resources only when running methods.
     @ray.remote
@@ -743,5 +738,4 @@ def test_creating_more_actors_than_resources(shutdown_only):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tests/test_advanced_3.py

@@ -272,14 +272,9 @@ class CaptureOutputAndError(object):
     """
 
     def __init__(self, captured_output_and_error):
-        if sys.version_info >= (3, 0):
-            import io
-            self.output_buffer = io.StringIO()
-            self.error_buffer = io.StringIO()
-        else:
-            import cStringIO
-            self.output_buffer = cStringIO.StringIO()
-            self.error_buffer = cStringIO.StringIO()
+        import io
+        self.output_buffer = io.StringIO()
+        self.error_buffer = io.StringIO()
         self.captured_output_and_error = captured_output_and_error
 
     def __enter__(self):

python/ray/tests/test_array.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+from importlib import reload
 import numpy as np
 from numpy.testing import assert_equal, assert_almost_equal
 import pytest
@@ -12,9 +13,6 @@ import ray.experimental.array.remote as ra
 import ray.experimental.array.distributed as da
 import ray.cluster_utils
 
-if sys.version_info >= (3, 0):
-    from importlib import reload
-
 
 @pytest.fixture
 def reload_modules():
@@ -220,5 +218,4 @@ def test_distributed_array_methods(ray_start_cluster_2_nodes, reload_modules):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tests/test_basic.py

@@ -63,9 +63,6 @@ def test_simple_serialization(ray_start_regular):
         np.float64(1.9),
     ]
 
-    if sys.version_info < (3, 0):
-        primitive_objects.append(long(0))  # noqa: E501,F821
-
     composite_objects = (
         [[obj]
          for obj in primitive_objects] + [(obj, )
@@ -185,17 +182,7 @@ def complex_serialization(use_pickle):
             assert obj1 == obj2, "Objects {} and {} are different.".format(
                 obj1, obj2)
 
-    if sys.version_info >= (3, 0):
-        long_extras = [0, np.array([["hi", u"hi"], [1.3, 1]])]
-    else:
-
-        long_extras = [
-            long(0),  # noqa: E501,F821
-            np.array([
-                ["hi", u"hi"],
-                [1.3, long(1)]  # noqa: E501,F821
-            ])
-        ]
+    long_extras = [0, np.array([["hi", u"hi"], [1.3, 1]])]
 
     PRIMITIVE_OBJECTS = [
         0, 0.0, 0.9, 1 << 62, 1 << 100, 1 << 999, [1 << 100, [1 << 100]], "a",
@@ -810,8 +797,6 @@ def test_keyword_args(ray_start_regular):
     assert ray.get(f3.remote(4)) == 4
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 @pytest.mark.parametrize(
     "ray_start_regular", [{
         "local_mode": True
@@ -847,8 +832,6 @@ def test_args_starkwargs(ray_start_regular):
     ray.get(remote_test_function.remote(local_method, actor_method))
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 @pytest.mark.parametrize(
     "ray_start_regular", [{
         "local_mode": True
@@ -890,8 +873,6 @@ def test_args_named_and_star(ray_start_regular):
     ray.get(remote_test_function.remote(local_method, actor_method))
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 @pytest.mark.parametrize(
     "ray_start_regular", [{
         "local_mode": True
@@ -1655,5 +1636,4 @@ def test_wait(ray_start_regular):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tests/test_debug_tools.py

@@ -51,7 +51,6 @@ def test_raylet_gdb(ray_gdb_start):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     # Make subprocess happy in bazel.
     os.environ["LC_ALL"] = "en_US.UTF-8"
     os.environ["LANG"] = "en_US.UTF-8"

python/ray/tests/test_failure.py

@@ -644,8 +644,6 @@ def test_warning_for_too_many_nested_tasks(shutdown_only):
     wait_for_errors(ray_constants.WORKER_POOL_LARGE_ERROR, 1)
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 def test_warning_for_many_duplicate_remote_functions_and_actors(shutdown_only):
     ray.init(num_cpus=1)
 

python/ray/tests/test_projects.py

@@ -9,17 +9,13 @@ import subprocess
 import yaml
 from click.testing import CliRunner
 import sys
+from unittest.mock import patch, DEFAULT
 
 from contextlib import contextmanager
 
 from ray.projects.scripts import session_start, session_execute
 import ray
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import patch, DEFAULT
-else:
-    from mock import patch, DEFAULT
-
 TEST_DIR = os.path.join(
     os.path.dirname(os.path.abspath(__file__)), "project_files")
 
@@ -240,7 +236,6 @@ def test_session_create_multiple():
 
 
 if __name__ == "__main__":
-    import sys
     # Make subprocess happy in bazel.
     os.environ["LC_ALL"] = "en_US.UTF-8"
     os.environ["LANG"] = "en_US.UTF-8"

python/ray/tests/test_stress_failure.py

@@ -299,8 +299,6 @@ def test_nondeterministic_task(ray_start_reconstruction):
 @pytest.mark.skipif(
     os.environ.get("RAY_USE_NEW_GCS") == "on",
     reason="Failing with new GCS API on Linux.")
-@pytest.mark.skipif(
-    sys.version_info < (3, 0), reason="This test requires Python 3.")
 @pytest.mark.parametrize(
     "ray_start_object_store_memory", [10**9], indirect=True)
 def test_driver_put_errors(ray_start_object_store_memory):
@@ -375,5 +373,4 @@ def test_driver_put_errors(ray_start_object_store_memory):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/function_runner.py

@@ -7,7 +7,6 @@ import time
 import inspect
 import threading
 import traceback
-import sys
 from six.moves import queue
 
 from ray.tune import track
@@ -249,10 +248,7 @@ def wrap_function(train_func):
 
     use_track = False
     try:
-        if sys.version_info >= (3, 3):
-            func_args = inspect.getfullargspec(train_func).args
-        else:
-            func_args = inspect.getargspec(train_func).args
+        func_args = inspect.getfullargspec(train_func).args
         use_track = ("reporter" not in func_args and len(func_args) == 1)
         if use_track:
             logger.info("tune.track signature detected.")

python/ray/tune/tests/test_checkpoint_manager.py

@@ -6,14 +6,10 @@ from __future__ import print_function
 import random
 import sys
 import unittest
+from unittest.mock import patch
 
 from ray.tune.checkpoint_manager import Checkpoint, CheckpointManager, logger
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import patch
-else:
-    from mock import patch
-
 
 class CheckpointManagerTest(unittest.TestCase):
     @staticmethod
@@ -108,5 +104,4 @@ class CheckpointManagerTest(unittest.TestCase):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/tests/test_cluster.py

@@ -9,6 +9,7 @@ import os
 import pytest
 import shutil
 import sys
+from unittest.mock import MagicMock
 
 import ray
 from ray import tune
@@ -23,11 +24,6 @@ from ray.tune.resources import Resources
 from ray.tune.trial_runner import TrialRunner
 from ray.tune.suggest import BasicVariantGenerator
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import MagicMock
-else:
-    from mock import MagicMock
-
 
 def _start_new_cluster():
     cluster = Cluster(
@@ -599,5 +595,4 @@ tune.run(
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/tests/test_progress_reporter.py

@@ -3,18 +3,13 @@ from __future__ import division
 from __future__ import print_function
 
 import collections
-import sys
 import time
 import unittest
+from unittest.mock import MagicMock
 
 from ray.tune.trial import Trial
 from ray.tune.progress_reporter import _fair_filter_trials
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import MagicMock
-else:
-    from mock import MagicMock
-
 
 class ProgressReporterTest(unittest.TestCase):
     def mock_trial(self, status, start_time):

python/ray/tune/tests/test_ray_trial_executor.py

@@ -6,6 +6,7 @@ from __future__ import print_function
 import json
 import sys
 import unittest
+from unittest.mock import patch
 
 import ray
 from ray.exceptions import RayTimeoutError
@@ -18,11 +19,6 @@ from ray.tune.trial import Trial, Checkpoint
 from ray.tune.resources import Resources
 from ray.cluster_utils import Cluster
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import patch
-else:
-    from mock import patch
-
 
 class RayTrialExecutorTest(unittest.TestCase):
     def setUp(self):
@@ -220,5 +216,4 @@ class LocalModeExecutorTest(RayTrialExecutorTest):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/tests/test_sync.py

@@ -8,6 +8,7 @@ import shutil
 import sys
 import tempfile
 import unittest
+from unittest.mock import patch
 
 import ray
 from ray.rllib import _register_all
@@ -16,11 +17,6 @@ from ray import tune
 from ray.tune import TuneError
 from ray.tune.syncer import CommandBasedClient
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import patch
-else:
-    from mock import patch
-
 
 class TestSyncFunctionality(unittest.TestCase):
     def setUp(self):
@@ -214,5 +210,4 @@ class TestSyncFunctionality(unittest.TestCase):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/tests/test_trial_runner_2.py

@@ -5,6 +5,7 @@ from __future__ import print_function
 import os
 import sys
 import unittest
+from unittest.mock import patch
 
 import ray
 from ray.rllib import _register_all
@@ -18,11 +19,6 @@ from ray.tune.trial_runner import TrialRunner
 from ray.tune.resources import Resources
 from ray.tune.suggest import BasicVariantGenerator
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import patch
-else:
-    from mock import patch
-
 
 def create_mock_components():
     class _MockScheduler(FIFOScheduler):
@@ -330,5 +326,4 @@ class TrialRunnerTest2(unittest.TestCase):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/tests/test_trial_scheduler.py

@@ -10,8 +10,9 @@ import numpy as np
 import sys
 import tempfile
 import shutil
-import ray
+from unittest.mock import MagicMock
 
+import ray
 from ray.tune.result import TRAINING_ITERATION
 from ray.tune.schedulers import (HyperBandScheduler, AsyncHyperBandScheduler,
                                  PopulationBasedTraining, MedianStoppingRule,
@@ -25,11 +26,6 @@ from ray.tune.resources import Resources
 from ray.rllib import _register_all
 _register_all()
 
-if sys.version_info >= (3, 3):
-    from unittest.mock import MagicMock
-else:
-    from mock import MagicMock
-
 
 def result(t, rew):
     return dict(
@@ -1195,5 +1191,4 @@ class AsyncHyperBandSuite(unittest.TestCase):
 
 if __name__ == "__main__":
     import pytest
-    import sys
     sys.exit(pytest.main(["-v", __file__]))

python/ray/tune/web_server.py

@@ -4,22 +4,16 @@ from __future__ import print_function
 
 import json
 import logging
-import sys
 import threading
 
+from urllib.parse import urljoin, urlparse
+from http.server import SimpleHTTPRequestHandler, HTTPServer
+
 import ray.cloudpickle as cloudpickle
 from ray.tune import TuneError
 from ray.tune.suggest import BasicVariantGenerator
 from ray.utils import binary_to_hex, hex_to_binary
 
-if sys.version_info[0] == 2:
-    from urlparse import urljoin, urlparse
-    from SimpleHTTPServer import SimpleHTTPRequestHandler
-    from SocketServer import TCPServer as HTTPServer
-elif sys.version_info[0] == 3:
-    from urllib.parse import urljoin, urlparse
-    from http.server import SimpleHTTPRequestHandler, HTTPServer
-
 logger = logging.getLogger(__name__)
 
 try:

python/ray/worker.py

@@ -61,8 +61,6 @@ LOCAL_MODE = 2
 
 ERROR_KEY_PREFIX = b"Error:"
 
-PY3 = sys.version_info.major >= 3
-
 # Logger for this module. It should be configured at the entry point
 # into the program using Ray. Ray provides a default configuration at
 # entry/init points.
@@ -1456,7 +1454,7 @@ def get(object_ids, timeout=None):
     worker = global_worker
     worker.check_connected()
 
-    if PY3 and hasattr(
+    if hasattr(
             worker,
             "core_worker") and worker.core_worker.current_actor_is_asyncio():
         raise RayError("Using blocking ray.get inside async actor. "
@@ -1575,7 +1573,7 @@ def wait(object_ids, num_returns=1, timeout=None):
     """
     worker = global_worker
 
-    if PY3 and hasattr(
+    if hasattr(
             worker,
             "core_worker") and worker.core_worker.current_actor_is_asyncio():
         raise RayError("Using blocking ray.wait inside async method. "