Rebasing docker#7031 into 1.26.x

----

Removed Python2 support

Closes: docker#6890

- Removed six
- Removed now useless check for version_info >= 2.7
- Removed now unused get_output_stream method
- Import unittest.mock directly.

How we removed six from docker-compose

We expect this to happen in a couple steps,

1. Remove six entirely, and remove python2.7 from requirements, setup, etc.
2. cleanup code that is left (All the conditionals that are now always True or False)
3. Remove all unnecessary `__future__` commands, by modifying the pre-commit-hook of python sourts to be `--py3-plus`

After removing all occurrances, we made sure `six` wasn't used anymore running a search for

```txt
six\.\w+\(([^()]+)\)
```
- We replaced all types for their corresponding python3 types. Note how
  six returns a tuple for the isinstance (since in python2 there are
  more than one type, but that isn't necessary in python3, so we removed
  the tuple and instead used the class directly)

We then searched for all instances where code could be pruned. (i.e., if/else clauses that now where always `True` or `False`)

After that,

- Removed inheritinng from `object` super class, it isn't necessary in python3
- `# coding ... utf-8` statements are not needed
- `super(ClassName, self)` can now be replaced with `super()`

Signed-off-by: Alejandro G. Recuenco <alejandrogonzalezrecuenco@gmail.com>

.pre-commit-config.yaml

@@ -17,9 +17,6 @@
   sha: v1.3.4
   hooks:
     - id: reorder-python-imports
-      language_version: 'python2.7'
+      language_version: 'python3.7'
       args:
-        - --add-import
-        - from __future__ import absolute_import
-        - --add-import
-        - from __future__ import unicode_literals
+         - --py3-plus

Dockerfile

@@ -24,8 +24,6 @@ RUN apk add --no-cache \
     musl-dev \
     openssl \
     openssl-dev \
-    python2 \
-    python2-dev \
     zlib-dev
 ENV BUILD_BOOTLOADER=1
 
@@ -40,7 +38,6 @@ RUN apt-get update && apt-get install --no-install-recommends -y \
     libssl-dev \
     make \
     openssl \
-    python2.7-dev \
     zlib1g-dev
 
 FROM build-${BUILD_PLATFORM} AS build

bin/docker-compose

@@ -1,6 +1,3 @@
 #!/usr/bin/env python
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from compose.cli.main import main
 main()

compose/__init__.py

@@ -1,4 +1,2 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
 
 __version__ = '1.26.0-rc1'

compose/__main__.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from compose.cli.main import main
 
 main()

compose/cli/colors.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from ..const import IS_WINDOWS_PLATFORM
 
 NAMES = [

compose/cli/command.py

@@ -1,12 +1,7 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import logging
 import os
 import re
 
-import six
-
 from . import errors
 from .. import config
 from .. import parallel
@@ -110,7 +105,7 @@ def get_config_from_options(base_dir, options, additional_options=None):
 
 def get_config_path_from_options(base_dir, options, environment):
     def unicode_paths(paths):
-        return [p.decode('utf-8') if isinstance(p, six.binary_type) else p for p in paths]
+        return [p.decode('utf-8') if isinstance(p, bytes) else p for p in paths]
 
     file_option = options.get('--file')
     if file_option:

compose/cli/docker_client.py

@@ -1,11 +1,7 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import logging
 import os.path
 import ssl
 
-import six
 from docker import APIClient
 from docker import Context
 from docker import ContextAPI
@@ -47,7 +43,7 @@ def get_client(environment, verbose=False, version=None, context=None):
         environment=environment, tls_version=get_tls_version(environment)
     )
     if verbose:
-        version_info = six.iteritems(client.version())
+        version_info = client.version().items()
         log.info(get_version_info('full'))
         log.info("Docker base_url: %s", client.base_url)
         log.info("Docker version: %s",

compose/cli/docopt_command.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from inspect import getdoc
 
 from docopt import docopt
@@ -14,7 +11,7 @@ def docopt_full_help(docstring, *args, **kwargs):
         raise SystemExit(docstring)
 
 
-class DocoptDispatcher(object):
+class DocoptDispatcher:
 
     def __init__(self, command_class, options):
         self.command_class = command_class
@@ -53,7 +50,7 @@ def get_handler(command_class, command):
 
 class NoSuchCommand(Exception):
     def __init__(self, command, supercommand):
-        super(NoSuchCommand, self).__init__("No such command: %s" % command)
+        super().__init__("No such command: %s" % command)
 
         self.command = command
         self.supercommand = supercommand

compose/cli/errors.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import contextlib
 import logging
 import socket

compose/cli/formatter.py

@@ -1,10 +1,6 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import logging
 import shutil
 
-import six
 import texttable
 
 from compose.cli import colors
@@ -57,7 +53,7 @@ def get_level_message(self, record):
         return ''
 
     def format(self, record):
-        if isinstance(record.msg, six.binary_type):
+        if isinstance(record.msg, bytes):
             record.msg = record.msg.decode('utf-8')
-        message = super(ConsoleWarningFormatter, self).format(record)
+        message = super().format(record)
         return '{0}{1}'.format(self.get_level_message(record), message)

compose/cli/log_printer.py

@@ -1,23 +1,19 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
+import _thread as thread
 import sys
 from collections import namedtuple
 from itertools import cycle
+from queue import Empty
+from queue import Queue
 from threading import Thread
 
 from docker.errors import APIError
-from six.moves import _thread as thread
-from six.moves.queue import Empty
-from six.moves.queue import Queue
 
 from . import colors
-from compose import utils
 from compose.cli.signals import ShutdownException
 from compose.utils import split_buffer
 
 
-class LogPresenter(object):
+class LogPresenter:
 
     def __init__(self, prefix_width, color_func):
         self.prefix_width = prefix_width
@@ -54,7 +50,7 @@ def max_name_width(service_names, max_index_width=3):
     return max(len(name) for name in service_names) + max_index_width
 
 
-class LogPrinter(object):
+class LogPrinter:
     """Print logs from many containers to a single output stream."""
 
     def __init__(self,
@@ -67,7 +63,7 @@ def __init__(self,
         self.containers = containers
         self.presenters = presenters
         self.event_stream = event_stream
-        self.output = utils.get_output_stream(output)
+        self.output = output
         self.cascade_stop = cascade_stop
         self.log_args = log_args or {}
 

compose/cli/main.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import contextlib
 import functools
 import json
@@ -180,7 +176,7 @@ def parse_doc_section(name, source):
     return [s.strip() for s in pattern.findall(source)]
 
 
-class TopLevelCommand(object):
+class TopLevelCommand:
     """Define and run multi-container applications with Docker.
 
     Usage:

compose/cli/signals.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import signal
 
 from ..const import IS_WINDOWS_PLATFORM

compose/cli/utils.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import unicode_literals
-
 import math
 import os
 import platform
@@ -10,7 +6,6 @@
 import sys
 
 import docker
-import six
 
 import compose
 from ..const import IS_WINDOWS_PLATFORM
@@ -144,7 +139,7 @@ def human_readable_file_size(size):
 
 
 def binarystr_to_unicode(s):
-    if not isinstance(s, six.binary_type):
+    if not isinstance(s, bytes):
         return s
 
     if IS_WINDOWS_PLATFORM:

compose/cli/verbose_proxy.py

@@ -1,17 +1,12 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import functools
 import logging
 import pprint
 from itertools import chain
 
-import six
-
 
 def format_call(args, kwargs):
     args = (repr(a) for a in args)
-    kwargs = ("{0!s}={1!r}".format(*item) for item in six.iteritems(kwargs))
+    kwargs = ("{0!s}={1!r}".format(*item) for item in kwargs.items())
     return "({0})".format(", ".join(chain(args, kwargs)))
 
 
@@ -27,7 +22,7 @@ def format_return(result, max_lines):
     return result
 
 
-class VerboseProxy(object):
+class VerboseProxy:
     """Proxy all function calls to another class and log method name, arguments
     and return values for each call.
     """
@@ -41,7 +36,7 @@ def __init__(self, obj_name, obj, log_name=None, max_lines=10):
     def __getattr__(self, name):
         attr = getattr(self.obj, name)
 
-        if not six.callable(attr):
+        if not callable(attr):
             return attr
 
         return functools.partial(self.proxy_callable, name)

compose/config/__init__.py

@@ -1,7 +1,4 @@
 # flake8: noqa
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from . import environment
 from .config import ConfigurationError
 from .config import DOCKER_CONFIG_KEYS

compose/config/config.py

@@ -1,6 +1,3 @@
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 import functools
 import io
 import logging
@@ -11,7 +8,6 @@
 from collections import namedtuple
 from operator import attrgetter
 
-import six
 import yaml
 from cached_property import cached_property
 
@@ -204,7 +200,7 @@ def version(self):
                         'Compose file version 1.'.format(self.filename))
             return V1
 
-        if not isinstance(version, six.string_types):
+        if not isinstance(version, str):
             raise ConfigurationError(
                 'Version in "{}" is invalid - it should be a string.'
                 .format(self.filename))
@@ -589,7 +585,7 @@ def process_config_file(config_file, environment, service_name=None, interpolate
     return config_file
 
 
-class ServiceExtendsResolver(object):
+class ServiceExtendsResolver:
     def __init__(self, service_config, config_file, environment, already_seen=None):
         self.service_config = service_config
         self.working_dir = service_config.working_dir
@@ -688,12 +684,12 @@ def resolve_environment(service_dict, environment=None):
         env.update(env_vars_from_file(env_file))
 
     env.update(parse_environment(service_dict.get('environment')))
-    return dict(resolve_env_var(k, v, environment) for k, v in six.iteritems(env))
+    return dict(resolve_env_var(k, v, environment) for k, v in env.items())
 
 
 def resolve_build_args(buildargs, environment):
     args = parse_build_arguments(buildargs)
-    return dict(resolve_env_var(k, v, environment) for k, v in six.iteritems(args))
+    return dict(resolve_env_var(k, v, environment) for k, v in args.items())
 
 
 def validate_extended_service_dict(service_dict, filename, service):
@@ -780,7 +776,7 @@ def process_service(service_config):
 
 
 def process_build_section(service_dict, working_dir):
-    if isinstance(service_dict['build'], six.string_types):
+    if isinstance(service_dict['build'], str):
         service_dict['build'] = resolve_build_path(working_dir, service_dict['build'])
     elif isinstance(service_dict['build'], dict):
         if 'context' in service_dict['build']:
@@ -848,7 +844,7 @@ def process_healthcheck(service_dict):
         hc['test'] = ['NONE']
 
     for field in ['interval', 'timeout', 'start_period']:
-        if field not in hc or isinstance(hc[field], six.integer_types):
+        if field not in hc or isinstance(hc[field], int):
             continue
         hc[field] = parse_nanoseconds_int(hc[field])
 
@@ -1179,7 +1175,7 @@ def parse_sequence_func(seq):
 def merge_build(output, base, override):
     def to_dict(service):
         build_config = service.get('build', {})
-        if isinstance(build_config, six.string_types):
+        if isinstance(build_config, str):
             return {'context': build_config}
         return build_config
 
@@ -1389,7 +1385,7 @@ def normalize_build(service_dict, working_dir, environment):
     if 'build' in service_dict:
         build = {}
         # Shortcut where specifying a string is treated as the build context
-        if isinstance(service_dict['build'], six.string_types):
+        if isinstance(service_dict['build'], str):
             build['context'] = service_dict.pop('build')
         else:
             build.update(service_dict['build'])
@@ -1415,7 +1411,7 @@ def validate_paths(service_dict):
     if 'build' in service_dict:
         build = service_dict.get('build', {})
 
-        if isinstance(build, six.string_types):
+        if isinstance(build, str):
             build_path = build
         elif isinstance(build, dict) and 'context' in build:
             build_path = build['context']
@@ -1506,7 +1502,7 @@ def merge_list_or_string(base, override):
 def to_list(value):
     if value is None:
         return []
-    elif isinstance(value, six.string_types):
+    elif isinstance(value, str):
         return [value]
     else:
         return value