Remove support for end-of-life Python 2.7 (#1318)

Remove support for end-of-life Python 2.7

Python 2.7 is end of life. It is no longer receiving bug fixes,
including for security issues. Python 2.7 went EOL on 2020-01-01. For
additional details on support Python versions, see:

Supported: https://devguide.python.org/#status-of-python-branches
EOL: https://devguide.python.org/devcycle/#end-of-life-branches

Removing support for EOL Pythons will reduce testing and maintenance
resources while allowing the library to move towards a modern Python 3
style. Python 2.7 users can continue to use the previous version of
redis-py.

Was able to simplify the code:

- Removed redis._compat module
- Removed __future__ imports
- Removed object from class definition (all classes are new style)
- Removed long (Python 3 unified numeric types)
- Removed deprecated __nonzero__ method
- Use simpler Python 3 super() syntax
- Use unified OSError exception
- Use yield from syntax

Co-authored-by: Andy McCurdy <andy@andymccurdy.com>

3 files changed, 7 insertions, 15 deletions

diff --git a/benchmarks/base.py b/benchmarks/base.py
index 44e9341..8c13afe 100644
--- a/benchmarks/base.py
+++ b/benchmarks/base.py
@@ -3,10 +3,9 @@ import itertools
 import redis
 import sys
 import timeit
-from redis._compat import izip
 
 
-class Benchmark(object):
+class Benchmark:
     ARGUMENTS = ()
 
     def __init__(self):
@@ -34,7 +33,7 @@ class Benchmark(object):
         group_names = [group['name'] for group in self.ARGUMENTS]
         group_values = [group['values'] for group in self.ARGUMENTS]
         for value_set in itertools.product(*group_values):
-            pairs = list(izip(group_names, value_set))
+            pairs = list(zip(group_names, value_set))
             arg_string = ', '.join(['%s=%s' % (p[0], p[1]) for p in pairs])
             sys.stdout.write('Benchmark: %s... ' % arg_string)
             sys.stdout.flush()
diff --git a/benchmarks/basic_operations.py b/benchmarks/basic_operations.py
index a4b675d..9446343 100644
--- a/benchmarks/basic_operations.py
+++ b/benchmarks/basic_operations.py
@@ -1,13 +1,8 @@
-from __future__ import print_function
 import redis
 import time
-import sys
 from functools import wraps
 from argparse import ArgumentParser
 
-if sys.version_info[0] == 3:
-    long = int
-
 
 def parse_args():
     parser = ArgumentParser()
@@ -47,9 +42,9 @@ def run():
 def timer(func):
     @wraps(func)
     def wrapper(*args, **kwargs):
-        start = time.clock()
+        start = time.monotonic()
         ret = func(*args, **kwargs)
-        duration = time.clock() - start
+        duration = time.monotonic() - start
         if 'num' in kwargs:
             count = kwargs['num']
         else:
@@ -57,7 +52,7 @@ def timer(func):
         print('{} - {} Requests'.format(func.__name__, count))
         print('Duration  = {}'.format(duration))
         print('Rate = {}'.format(count/duration))
-        print('')
+        print()
         return ret
     return wrapper
 
@@ -185,7 +180,6 @@ def hmset(conn, num, pipeline_size, data_size):
 
     set_data = {'str_value': 'string',
                 'int_value': 123456,
-                'long_value': long(123456),
                 'float_value': 123456.0}
     for i in range(num):
         conn.hmset('hmset_key', set_data)
diff --git a/benchmarks/command_packer_benchmark.py b/benchmarks/command_packer_benchmark.py
index 1216df6..823a8c8 100644
--- a/benchmarks/command_packer_benchmark.py
+++ b/benchmarks/command_packer_benchmark.py
@@ -1,7 +1,6 @@
 import socket
 from redis.connection import (Connection, SYM_STAR, SYM_DOLLAR, SYM_EMPTY,
                               SYM_CRLF)
-from redis._compat import imap
 from base import Benchmark
 
 
@@ -29,7 +28,7 @@ class StringJoiningConnection(Connection):
         args_output = SYM_EMPTY.join([
             SYM_EMPTY.join(
                 (SYM_DOLLAR, str(len(k)).encode(), SYM_CRLF, k, SYM_CRLF))
-            for k in imap(self.encoder.encode, args)])
+            for k in map(self.encoder.encode, args)])
         output = SYM_EMPTY.join(
             (SYM_STAR, str(len(args)).encode(), SYM_CRLF, args_output))
         return output
@@ -61,7 +60,7 @@ class ListJoiningConnection(Connection):
         buff = SYM_EMPTY.join(
             (SYM_STAR, str(len(args)).encode(), SYM_CRLF))
 
-        for k in imap(self.encoder.encode, args):
+        for k in map(self.encoder.encode, args):
             if len(buff) > 6000 or len(k) > 6000:
                 buff = SYM_EMPTY.join(
                     (buff, SYM_DOLLAR, str(len(k)).encode(), SYM_CRLF))