Remove some remnants of Python2 (#1172)

Co-authored-by: vgali7 <vgali7@gatech.edu>

.gitignore

@@ -42,3 +42,6 @@ tests/unit/cython/bytesio_testhelper.c
 #iPython
 *.ipynb
 
+venv
+docs/venv
+.eggs

CONTRIBUTING.rst

@@ -26,7 +26,6 @@ To protect the community, all contributors are required to `sign the DataStax Co
 
 Design and Implementation Guidelines
 ------------------------------------
-- We support Python 2.7+, so any changes must work in any of these runtimes (we use ``six``, ``futures``, and some internal backports for compatability)
 - We have integrations (notably Cassandra cqlsh) that require pure Python and minimal external dependencies. We try to avoid new external dependencies. Where compiled extensions are concerned, there should always be a pure Python fallback implementation.
 - This project follows `semantic versioning <http://semver.org/>`_, so breaking API changes will only be introduced in major versions.
 - Legacy ``cqlengine`` has varying degrees of overreaching client-side validation. Going forward, we will avoid client validation where server feedback is adequate and not overly expensive.

appveyor.yml

@@ -1,9 +1,6 @@
 environment:
   matrix:
-    - PYTHON: "C:\\Python27-x64"
-      cassandra_version: 3.11.2
-      ci_type: standard
-    - PYTHON: "C:\\Python35-x64"
+    - PYTHON: "C:\\Python37-x64"
       cassandra_version: 3.11.2
       ci_type: standard
 os: Visual Studio 2015

benchmarks/callback_full_pipeline.py

@@ -18,7 +18,6 @@
 from threading import Event
 
 from base import benchmark, BenchmarkThread
-from six.moves import range
 
 log = logging.getLogger(__name__)
 

benchmarks/future_batches.py

@@ -14,7 +14,7 @@
 
 import logging
 from base import benchmark, BenchmarkThread
-from six.moves import queue
+import queue
 
 log = logging.getLogger(__name__)
 

benchmarks/future_full_pipeline.py

@@ -14,7 +14,7 @@
 
 import logging
 from base import benchmark, BenchmarkThread
-from six.moves import queue
+import queue
 
 log = logging.getLogger(__name__)
 

benchmarks/sync.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 from base import benchmark, BenchmarkThread
-from six.moves import range
 
 
 class Runner(BenchmarkThread):

cassandra/auth.py

@@ -32,8 +32,6 @@
 except ImportError:
     SASLClient = None
 
-import six
-
 log = logging.getLogger(__name__)
 
 # Custom payload keys related to DSE Unified Auth
@@ -270,15 +268,15 @@ def __init__(self, username, password):
         self.password = password
 
     def get_mechanism(self):
-        return six.b("PLAIN")
+        return b"PLAIN"
 
     def get_initial_challenge(self):
-        return six.b("PLAIN-START")
+        return b"PLAIN-START"
 
     def evaluate_challenge(self, challenge):
-        if challenge == six.b('PLAIN-START'):
+        if challenge == b'PLAIN-START':
             data = "\x00%s\x00%s" % (self.username, self.password)
-            return data if six.PY2 else data.encode()
+            return data.encode()
         raise Exception('Did not receive a valid challenge response from server')
 
 
@@ -297,13 +295,13 @@ def __init__(self, host, service, qops, properties):
         self.sasl = SASLClient(host, service, 'GSSAPI', qops=qops, **properties)
 
     def get_mechanism(self):
-        return six.b("GSSAPI")
+        return b"GSSAPI"
 
     def get_initial_challenge(self):
-        return six.b("GSSAPI-START")
+        return b"GSSAPI-START"
 
     def evaluate_challenge(self, challenge):
-        if challenge == six.b('GSSAPI-START'):
+        if challenge == b'GSSAPI-START':
             return self.sasl.process()
         else:
             return self.sasl.process(challenge)

cassandra/cluster.py

@@ -21,6 +21,7 @@
 import atexit
 from binascii import hexlify
 from collections import defaultdict
+from collections.abc import Mapping
 from concurrent.futures import ThreadPoolExecutor, FIRST_COMPLETED, wait as wait_futures
 from copy import copy
 from functools import partial, wraps
@@ -29,8 +30,8 @@
 import logging
 from warnings import warn
 from random import random
-import six
-from six.moves import filter, range, queue as Queue
+import re
+import queue
 import socket
 import sys
 import time
@@ -79,7 +80,6 @@
                              HostTargetingStatement)
 from cassandra.marshal import int64_pack
 from cassandra.timestamps import MonotonicTimestampGenerator
-from cassandra.compat import Mapping
 from cassandra.util import _resolve_contact_points_to_string_map, Version
 
 from cassandra.datastax.insights.reporter import MonitorReporter
@@ -111,9 +111,6 @@
 except ImportError:
     from cassandra.util import WeakSet  # NOQA
 
-if six.PY3:
-    long = int
-
 def _is_eventlet_monkey_patched():
     if 'eventlet.patcher' not in sys.modules:
         return False
@@ -1158,7 +1155,7 @@ def __init__(self,
             else:
                 self._contact_points_explicit = True
 
-            if isinstance(contact_points, six.string_types):
+            if isinstance(contact_points, str):
                 raise TypeError("contact_points should not be a string, it should be a sequence (e.g. list) of strings")
 
             if None in contact_points:
@@ -1793,8 +1790,8 @@ def _new_session(self, keyspace):
         return session
 
     def _session_register_user_types(self, session):
-        for keyspace, type_map in six.iteritems(self._user_types):
-            for udt_name, klass in six.iteritems(type_map):
+        for keyspace, type_map in self._user_types.items():
+            for udt_name, klass in type_map.items():
                 session.user_type_registered(keyspace, udt_name, klass)
 
     def _cleanup_failed_on_up_handling(self, host):
@@ -2683,7 +2680,7 @@ def execute_async(self, query, parameters=None, trace=False, custom_payload=None
         """
         custom_payload = custom_payload if custom_payload else {}
         if execute_as:
-            custom_payload[_proxy_execute_key] = six.b(execute_as)
+            custom_payload[_proxy_execute_key] = execute_as.encode()
 
         future = self._create_response_future(
             query, parameters, trace, custom_payload, timeout,
@@ -2747,8 +2744,8 @@ def execute_graph_async(self, query, parameters=None, trace=False, execution_pro
 
         custom_payload = execution_profile.graph_options.get_options_map()
         if execute_as:
-            custom_payload[_proxy_execute_key] = six.b(execute_as)
-        custom_payload[_request_timeout_key] = int64_pack(long(execution_profile.request_timeout * 1000))
+            custom_payload[_proxy_execute_key] = execute_as.encode()
+        custom_payload[_request_timeout_key] = int64_pack(int(execution_profile.request_timeout * 1000))
 
         future = self._create_response_future(query, parameters=None, trace=trace, custom_payload=custom_payload,
                                               timeout=_NOT_SET, execution_profile=execution_profile)
@@ -2885,7 +2882,7 @@ def _create_response_future(self, query, parameters, trace, custom_payload,
 
         prepared_statement = None
 
-        if isinstance(query, six.string_types):
+        if isinstance(query, str):
             query = SimpleStatement(query)
         elif isinstance(query, PreparedStatement):
             query = query.bind(parameters)
@@ -3353,10 +3350,6 @@ def user_type_registered(self, keyspace, user_type, klass):
                 'User type %s does not exist in keyspace %s' % (user_type, keyspace))
 
         field_names = type_meta.field_names
-        if six.PY2:
-            # go from unicode to string to avoid decode errors from implicit
-            # decode when formatting non-ascii values
-            field_names = [fn.encode('utf-8') for fn in field_names]
 
         def encode(val):
             return '{ %s }' % ' , '.join('%s : %s' % (
@@ -4035,7 +4028,7 @@ def _get_schema_mismatches(self, peers_result, local_result, local_address):
             log.debug("[control connection] Schemas match")
             return None
 
-        return dict((version, list(nodes)) for version, nodes in six.iteritems(versions))
+        return dict((version, list(nodes)) for version, nodes in versions.items())
 
     def _get_peers_query(self, peers_query_type, connection=None):
         """
@@ -4155,7 +4148,7 @@ class _Scheduler(Thread):
     is_shutdown = False
 
     def __init__(self, executor):
-        self._queue = Queue.PriorityQueue()
+        self._queue = queue.PriorityQueue()
         self._scheduled_tasks = set()
         self._count = count()
         self._executor = executor
@@ -4213,7 +4206,7 @@ def run(self):
                     else:
                         self._queue.put_nowait((run_at, i, task))
                         break
-            except Queue.Empty:
+            except queue.Empty:
                 pass
 
             time.sleep(0.1)

cassandra/concurrent.py

@@ -16,8 +16,6 @@
 from collections import namedtuple
 from heapq import heappush, heappop
 from itertools import cycle
-import six
-from six.moves import xrange, zip
 from threading import Condition
 import sys
 
@@ -119,7 +117,7 @@ def execute(self, concurrency, fail_fast):
         self._current = 0
         self._exec_count = 0
         with self._condition:
-            for n in xrange(concurrency):
+            for n in range(concurrency):
                 if not self._execute_next():
                     break
         return self._results()
@@ -143,17 +141,13 @@ def _execute(self, idx, statement, params):
                 callback=self._on_success, callback_args=args,
                 errback=self._on_error, errback_args=args)
         except Exception as exc:
-            # exc_info with fail_fast to preserve stack trace info when raising on the client thread
-            # (matches previous behavior -- not sure why we wouldn't want stack trace in the other case)
-            e = sys.exc_info() if self._fail_fast and six.PY2 else exc
-
             # If we're not failing fast and all executions are raising, there is a chance of recursing
             # here as subsequent requests are attempted. If we hit this threshold, schedule this result/retry
             # and let the event loop thread return.
             if self._exec_depth < self.max_error_recursion:
-                self._put_result(e, idx, False)
+                self._put_result(exc, idx, False)
             else:
-                self.session.submit(self._put_result, e, idx, False)
+                self.session.submit(self._put_result, exc, idx, False)
         self._exec_depth -= 1
 
     def _on_success(self, result, future, idx):
@@ -163,14 +157,6 @@ def _on_success(self, result, future, idx):
     def _on_error(self, result, future, idx):
         self._put_result(result, idx, False)
 
-    @staticmethod
-    def _raise(exc):
-        if six.PY2 and isinstance(exc, tuple):
-            (exc_type, value, traceback) = exc
-            six.reraise(exc_type, value, traceback)
-        else:
-            raise exc
-
 
 class ConcurrentExecutorGenResults(_ConcurrentExecutor):
 
@@ -190,7 +176,7 @@ def _results(self):
                     try:
                         self._condition.release()
                         if self._fail_fast and not res[0]:
-                            self._raise(res[1])
+                            raise res[1]
                         yield res
                     finally:
                         self._condition.acquire()
@@ -221,9 +207,9 @@ def _results(self):
             while self._current < self._exec_count:
                 self._condition.wait()
                 if self._exception and self._fail_fast:
-                    self._raise(self._exception)
+                    raise self._exception
         if self._exception and self._fail_fast:  # raise the exception even if there was no wait
-            self._raise(self._exception)
+            raise self._exception
         return [r[1] for r in sorted(self._results_queue)]
 
 

cassandra/connection.py

@@ -19,8 +19,6 @@
 from heapq import heappush, heappop
 import io
 import logging
-import six
-from six.moves import range
 import socket
 import struct
 import sys
@@ -33,7 +31,7 @@
 if 'gevent.monkey' in sys.modules:
     from gevent.queue import Queue, Empty
 else:
-    from six.moves.queue import Queue, Empty  # noqa
+    from queue import Queue, Empty  # noqa
 
 from cassandra import ConsistencyLevel, AuthenticationFailed, OperationTimedOut, ProtocolVersion
 from cassandra.marshal import int32_pack
@@ -605,12 +603,6 @@ def wrapper(self, *args, **kwargs):
 
 DEFAULT_CQL_VERSION = '3.0.0'
 
-if six.PY3:
-    def int_from_buf_item(i):
-        return i
-else:
-    int_from_buf_item = ord
-
 
 class _ConnectionIOBuffer(object):
     """
@@ -1122,7 +1114,7 @@ def _read_frame_header(self):
         buf = self._io_buffer.cql_frame_buffer.getvalue()
         pos = len(buf)
         if pos:
-            version = int_from_buf_item(buf[0]) & PROTOCOL_VERSION_MASK
+            version = buf[0] & PROTOCOL_VERSION_MASK
             if version not in ProtocolVersion.SUPPORTED_VERSIONS:
                 raise ProtocolError("This version of the driver does not support protocol version %d" % version)
             frame_header = frame_header_v3 if version >= 3 else frame_header_v1_v2
@@ -1321,7 +1313,7 @@ def _handle_options_response(self, options_response):
                           remote_supported_compressions)
             else:
                 compression_type = None
-                if isinstance(self.compression, six.string_types):
+                if isinstance(self.compression, str):
                     # the user picked a specific compression type ('snappy' or 'lz4')
                     if self.compression not in remote_supported_compressions:
                         raise ProtocolError(

cassandra/cqlengine/__init__.py

@@ -12,9 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import six
-
-
 # Caching constants.
 CACHING_ALL = "ALL"
 CACHING_KEYS_ONLY = "KEYS_ONLY"
@@ -31,7 +28,4 @@ class ValidationError(CQLEngineException):
 
 
 class UnicodeMixin(object):
-    if six.PY3:
-        __str__ = lambda x: x.__unicode__()
-    else:
-        __str__ = lambda x: six.text_type(x).encode('utf-8')
+    __str__ = lambda x: x.__unicode__()