Drop Python2 support

.github/workflows/workflow.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [2.7, 3.6, 3.7]
+        python-version: [3.6, 3.7]
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python ${{ matrix.python-version }}
@@ -23,13 +23,6 @@ jobs:
         run: |
           flake8 .
 
-      - name: Lint Examples
-        # some examples are py3 only
-        if: matrix.python-version != 2.7
-        run: |
-          cd examples
-          flake8 .
-
   unittest:
     runs-on: ubuntu-latest
     strategy:

.travis.yml

-sudo: false
-dist: trusty
-language: python
-
-cache:
-  pip: true
-  apt: true
-  directories:
-    - $HOME/tensorpack_data
-
-addons:
-  apt:
-    packages:
-    - libprotobuf-dev
-    - protobuf-compiler
-
-# Test with TF 1.3-latest
-matrix:
-  fast_finish: true
-  include:
-  - os: linux
-    python: 2.7
-    env: TF_VERSION=1.3.0
-  - os: linux
-    python: 2.7
-    env: TF_VERSION=1.14.0
-  - os: linux
-    python: 2.7
-    env: TF_VERSION=nightly
-  allow_failures:
-  - env: TF_VERSION=nightly
-
-install:
-- pip install -U pip    # the pip version on travis is too old
-- pip install .
-- pip install scikit-image opencv-python lmdb h5py msgpack
-  # check that dataflow can be imported alone without tensorflow
-- python -c "import tensorpack.dataflow"
-- ./tests/install-tensorflow.sh
-
-before_script:
-- protoc --version
-- python -c "import cv2; print('OpenCV '+ cv2.__version__)"
-- python -c "import tensorflow as tf; print('TensorFlow '+ tf.__version__)"
-- mkdir -p $HOME/tensorpack_data
-- export TENSORPACK_DATASET=$HOME/tensorpack_data
-
-script:
-- $TRAVIS_BUILD_DIR/tests/run-tests.sh
-- cd $TRAVIS_BUILD_DIR  # go back to root so that deploy may work
-
-notifications:
-  email:
-    recipients:
-      - ppwwyyxxc@gmail.com
-    on_success: never
-    on_failure: always
-  webhooks:
-    urls:
-      - https://webhooks.gitter.im/e/cede9dbbf6630b3704b3
-    on_success: change  # options: [always|never|change] default: always
-    on_failure: always  # options: [always|never|change] default: always
-    on_start: never     # options: [always|never|change] default: always
-
-
-# see https://docs.travis-ci.com/user/deployment/pypi/
-#deploy:
-#- provider: pypi
-  #user: ppwwyyxx
-  #distributions: "sdist bdist_wheel"
-  #skip_upload_docs: true
-  #password:
-    #secure: 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
-  #on:
-    #tags: true
-    #branch: master
-    #repo: tensorpack/tensorpack
-    #python: "3.6"
-    #condition: "$PYPI = true"
-
-#- provider: pypi
-  #server: https://testpypi.python.org/pypi
-  #user: ppwwyyxx
-  #distributions: "sdist bdist_wheel"
-  #skip_upload_docs: true
-  #password:
-    #secure: 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
-  #on:
-    #branch: test-travis
-    #repo: tensorpack/tensorpack
-    #python: "3.6"
-    #condition: "$PYPI = true"

README.md

@@ -66,7 +66,7 @@ demonstrating its __flexibility__ for actual research.
 
 Dependencies:
 
-+ Python 2.7 or 3.3+. Python 2.7 is supported until [it retires in 2020](https://pythonclock.org/).
++ Python 3.3+.
 + Python bindings for OpenCV. (Optional, but required by a lot of features)
 + TensorFlow ≥ 1.3, < 2. (Not required if you only want to use `tensorpack.dataflow` alone as a data processing library)
 ```

examples/A3C-Gym/train-atari.py

@@ -9,11 +9,13 @@ import gym
 import multiprocessing as mp
 import numpy as np
 import os
-import six
 import sys
 import uuid
 import tensorflow as tf
 from six.moves import queue
+from concurrent import futures
+CancelledError = futures.CancelledError
+
 
 from tensorpack import *
 from tensorpack.tfutils.gradproc import MapGradient, SummaryGradient
@@ -25,12 +27,6 @@ from atari_wrapper import FireResetEnv, FrameStack, LimitLength, MapState
 from common import Evaluator, eval_model_multithread, play_n_episodes
 from simulator import SimulatorMaster, SimulatorProcess, TransitionExperience
 
-if six.PY3:
-    from concurrent import futures
-    CancelledError = futures.CancelledError
-else:
-    CancelledError = Exception
-
 IMAGE_SIZE = (84, 84)
 FRAME_HISTORY = 4
 GAMMA = 0.99

examples/CTC-TIMIT/timitdata.py

@@ -3,7 +3,6 @@
 # Author: Yuxin Wu
 
 import numpy as np
-from six.moves import range
 
 from tensorpack import ProxyDataFlow
 

examples/CTC-TIMIT/train-timit.py

@@ -6,7 +6,6 @@
 import argparse
 import os
 import tensorflow as tf
-from six.moves import range
 
 from tensorpack import *
 from tensorpack.tfutils.gradproc import GlobalNormClip, SummaryGradient

examples/Char-RNN/char-rnn.py

@@ -9,9 +9,7 @@ import operator
 import os
 import sys
 from collections import Counter
-import six
 import tensorflow as tf
-from six.moves import range
 
 from tensorpack import *
 from tensorpack.tfutils import optimizer, summary
@@ -44,8 +42,6 @@ class CharRNNData(RNGDataFlow):
         # preprocess data
         with open(input_file, 'rb') as f:
             data = f.read()
-        if six.PY2:
-            data = bytearray(data)
         data = [chr(c) for c in data if c < 128]
         counter = Counter(data)
         char_cnt = sorted(counter.items(), key=operator.itemgetter(1), reverse=True)

examples/DeepQNetwork/atari.py

@@ -11,7 +11,6 @@ import six
 from atari_py.ale_python_interface import ALEInterface
 from gym import spaces
 from gym.envs.atari.atari_env import ACTION_MEANING
-from six.moves import range
 
 from tensorpack.utils import logger, execute_only_once, get_rng
 from tensorpack.utils.fs import get_dataset_path

examples/DynamicFilterNetwork/steering-filter.py

@@ -8,7 +8,6 @@ import numpy as np
 import cv2
 import tensorflow as tf
 from scipy.signal import convolve2d
-from six.moves import range, zip
 
 from tensorpack import *
 from tensorpack.dataflow import dataset

examples/FasterRCNN/README.md

@@ -16,8 +16,7 @@ with the support of:
 This is likely the best-performing open source TensorFlow reimplementation of the above papers.
 
 ## Dependencies
-+ Python 3.3+; OpenCV
-+ TensorFlow ≥ 1.6
++ OpenCV, TensorFlow ≥ 1.6
 + pycocotools/scipy: `for i in cython 'git+https://github.com/cocodataset/cocoapi.git#subdirectory=PythonAPI' scipy; do pip install $i; done`
 + Pre-trained [ImageNet ResNet model](http://models.tensorpack.com/#FasterRCNN)
   from tensorpack model zoo

examples/FasterRCNN/predict.py

@@ -7,11 +7,8 @@ import os
 import shutil
 import tensorflow as tf
 import cv2
-import six
 import tqdm
 
-assert six.PY3, "This example requires Python 3!"
-
 import tensorpack.utils.viz as tpviz
 from tensorpack.predict import MultiTowerOfflinePredictor, OfflinePredictor, PredictConfig
 from tensorpack.tfutils import SmartInit, get_tf_version_tuple

examples/FasterRCNN/train.py

@@ -3,8 +3,6 @@
 # File: train.py
 
 import argparse
-import six
-assert six.PY3, "This example requires Python 3!"
 
 from tensorpack import *
 from tensorpack.tfutils import collect_env_info

examples/FasterRCNN/viz.py

@@ -2,7 +2,6 @@
 # File: viz.py
 
 import numpy as np
-from six.moves import zip
 
 from tensorpack.utils import viz
 from tensorpack.utils.palette import PALETTE_RGB

examples/GAN/DiscoGAN-CelebA.py

@@ -7,7 +7,6 @@ import argparse
 import numpy as np
 import os
 import tensorflow as tf
-from six.moves import map, zip
 
 from tensorpack import *
 from tensorpack.tfutils.scope_utils import auto_reuse_variable_scope

examples/HED/hed.py

@@ -8,7 +8,6 @@ import numpy as np
 import os
 import cv2
 import tensorflow as tf
-from six.moves import zip
 
 from tensorpack import *
 from tensorpack.dataflow import dataset

setup.py

@@ -61,14 +61,11 @@ setup(
         "msgpack-numpy>=0.4.4.2",
         "pyzmq>=16",
         "psutil>=5",
-        "subprocess32; python_version < '3.0'",
-        "functools32; python_version < '3.0'",
     ],
     tests_require=['flake8', 'scikit-image'],
     extras_require={
         'all': ['scipy', 'h5py', 'lmdb>=0.92', 'matplotlib', 'scikit-learn'],
         'all: "linux" in sys_platform': ['python-prctl'],
-        'all: python_version < "3.0"': ['tornado'],
     },
 
     # https://packaging.python.org/guides/distributing-packages-using-setuptools/#universal-wheels

tensorpack/callbacks/graph.py

@@ -6,7 +6,6 @@
 
 import numpy as np
 import os
-from six.moves import zip
 
 from ..compat import tfv1 as tf
 from ..tfutils.common import get_op_tensor_name

tensorpack/callbacks/group.py

@@ -4,8 +4,7 @@
 
 import traceback
 from contextlib import contextmanager
-from time import time as timer
-import six
+from time import perf_counter as timer  # noqa
 from ..compat import tfv1 as tf
 
 from ..utils import logger
@@ -13,9 +12,6 @@ from ..utils.utils import humanize_time_delta
 from .base import Callback
 from .hooks import CallbackToHook
 
-if six.PY3:
-    from time import perf_counter as timer  # noqa
-
 __all__ = ['Callbacks']
 
 

tensorpack/callbacks/inference.py

@@ -5,7 +5,6 @@
 import numpy as np
 from abc import ABCMeta
 import six
-from six.moves import zip
 
 from ..tfutils.common import get_op_tensor_name
 from ..utils import logger

tensorpack/callbacks/inference_runner.py

@@ -6,7 +6,6 @@ import itertools
 import sys
 from contextlib import contextmanager
 import tqdm
-from six.moves import range
 from tensorflow.python.training.monitored_session import _HookedSession as HookedSession
 
 from ..compat import tfv1 as tf

tensorpack/callbacks/param_test.py

 # -*- coding: utf-8 -*-
 import unittest
 import tensorflow as tf
-import six
 
 from ..utils import logger
 from ..train.trainers import NoOpTrainer
@@ -74,7 +73,6 @@ class ScheduledHyperParamSetterTest(unittest.TestCase):
         history = self._create_trainer_with_scheduler(scheduler, 1, 92, starting_epoch=90)
         self.assertEqual(len(history), 0)
 
-    @unittest.skipIf(six.PY2, "assertLogs not supported in Python 2")
     def testWarningStartInTheMiddle(self):
         scheduler = ScheduledHyperParamSetter(
             ObjAttrParam(self._param_obj, ParamObject.PARAM_NAME),
@@ -82,7 +80,6 @@ class ScheduledHyperParamSetterTest(unittest.TestCase):
         with self.assertLogs(logger=logger._logger, level='WARNING'):
             self._create_trainer_with_scheduler(scheduler, 1, 21, starting_epoch=20)
 
-    @unittest.skipIf(six.PY2, "unittest.mock not available in Python 2")
     def testNoWarningStartInTheMiddle(self):
         scheduler = ScheduledHyperParamSetter(
             ObjAttrParam(self._param_obj, ParamObject.PARAM_NAME),

tensorpack/dataflow/common.py

@@ -9,7 +9,6 @@ from collections import defaultdict, deque
 from copy import copy
 import six
 import tqdm
-from six.moves import map, range
 from termcolor import colored
 
 from ..utils import logger

tensorpack/dataflow/dataset/caltech101.py

@@ -3,7 +3,6 @@
 
 
 import os
-from six.moves import range
 
 from ...utils import logger
 from ...utils.fs import download, get_dataset_path

tensorpack/dataflow/dataset/cifar.py

@@ -7,8 +7,6 @@ import numpy as np
 import os
 import pickle
 import tarfile
-import six
-from six.moves import range
 
 from ...utils import logger
 from ...utils.fs import download, get_dataset_path
@@ -44,10 +42,7 @@ def read_cifar(filenames, cifar_classnum):
     ret = []
     for fname in filenames:
         fo = open(fname, 'rb')
-        if six.PY3:
-            dic = pickle.load(fo, encoding='bytes')
-        else:
-            dic = pickle.load(fo)
+        dic = pickle.load(fo, encoding='bytes')
         data = dic[b'data']
         if cifar_classnum == 10:
             label = dic[b'labels']

tensorpack/dataflow/dataset/mnist.py

@@ -5,7 +5,6 @@
 import gzip
 import numpy
 import os
-from six.moves import range
 
 from ...utils import logger
 from ...utils.fs import download, get_dataset_path

tensorpack/dataflow/format.py

@@ -5,7 +5,6 @@
 import numpy as np
 import os
 import six
-from six.moves import range
 
 from ..utils import logger
 from ..utils.argtools import log_once

tensorpack/dataflow/imgaug/base.py

@@ -6,7 +6,6 @@ import inspect
 import pprint
 from collections import namedtuple
 import weakref
-import six
 
 from ...utils.argtools import log_once
 from ...utils.utils import get_rng
@@ -34,32 +33,21 @@ def _default_repr(self):
     It assumes that the instance `self` contains attributes that match its constructor.
     """
     classname = type(self).__name__
-    if six.PY2:
-        argspec = inspect.getargspec(self.__init__)
-        assert argspec.varargs is None, "The default __repr__ in {} doesn't work for varargs!".format(classname)
-        assert argspec.keywords is None, "The default __repr__ in {} doesn't work for kwargs!".format(classname)
-        fields = argspec.args[1:]
-        defaults = {}
-        defaults_list = argspec.defaults
-        if defaults_list is not None:
-            for f, d in zip(fields[::-1], defaults_list[::-1]):
-                defaults[f] = d
-    else:
-        argspec = inspect.getfullargspec(self.__init__)
-        assert argspec.varargs is None, "The default __repr__ in {} doesn't work for varargs!".format(classname)
-        assert argspec.varkw is None, "The default __repr__ in {} doesn't work for kwargs!".format(classname)
-        defaults = {}
-
-        fields = argspec.args[1:]
-        defaults_pos = argspec.defaults
-        if defaults_pos is not None:
-            for f, d in zip(fields[::-1], defaults_pos[::-1]):
-                defaults[f] = d
-
-        for k in argspec.kwonlyargs:
-            fields.append(k)
-            if k in argspec.kwonlydefaults:
-                defaults[k] = argspec.kwonlydefaults[k]
+    argspec = inspect.getfullargspec(self.__init__)
+    assert argspec.varargs is None, "The default __repr__ in {} doesn't work for varargs!".format(classname)
+    assert argspec.varkw is None, "The default __repr__ in {} doesn't work for kwargs!".format(classname)
+    defaults = {}
+
+    fields = argspec.args[1:]
+    defaults_pos = argspec.defaults
+    if defaults_pos is not None:
+        for f, d in zip(fields[::-1], defaults_pos[::-1]):
+            defaults[f] = d
+
+    for k in argspec.kwonlyargs:
+        fields.append(k)
+        if k in argspec.kwonlydefaults:
+            defaults[k] = argspec.kwonlydefaults[k]
 
     argstr = []
     for idx, f in enumerate(fields):

tensorpack/dataflow/raw.py

@@ -5,7 +5,6 @@
 import copy
 import numpy as np
 import six
-from six.moves import range
 
 from .base import DataFlow, RNGDataFlow
 

tensorpack/dataflow/remote.py

@@ -6,7 +6,6 @@ import multiprocessing as mp
 import time
 from collections import deque
 import tqdm
-from six.moves import range
 
 from ..utils import logger
 from ..utils.concurrency import DIE

tensorpack/graph_builder/distributed.py

@@ -3,7 +3,6 @@
 
 import re
 import tensorflow as tf
-from six.moves import range
 
 from ..tfutils.common import get_global_step_var, get_op_tensor_name
 from ..utils import logger

tensorpack/graph_builder/training.py

@@ -8,7 +8,6 @@ from abc import ABCMeta, abstractmethod
 from contextlib import contextmanager
 import six
 import tensorflow as tf
-from six.moves import range, zip
 
 from ..compat import tfv1
 from ..tfutils.common import get_tf_version_tuple

tensorpack/input_source/input_source.py

@@ -6,7 +6,6 @@ import threading
 from contextlib import contextmanager
 from itertools import chain
 import tensorflow as tf
-from six.moves import range, zip
 
 from ..compat import tfv1
 from ..callbacks.base import Callback, CallbackFactory

tensorpack/input_source/input_source_base.py

@@ -6,7 +6,6 @@ from abc import ABCMeta, abstractmethod
 from contextlib import contextmanager
 import six
 import tensorflow as tf
-from six.moves import zip
 
 from ..callbacks.base import CallbackFactory
 from ..tfutils.common import get_op_tensor_name

tensorpack/models/batch_norm.py

@@ -3,7 +3,6 @@
 
 
 import re
-import six
 from ..compat import tfv1 as tf  # this should be avoided first in model code
 from tensorflow.python.training import moving_averages
 
@@ -292,7 +291,7 @@ def BatchNorm(inputs, axis=None, training=None, momentum=0.9, epsilon=1e-5,
             if num_dev == 1:
                 logger.warn("BatchNorm(sync_statistics='nccl') is used with only one tower!")
             else:
-                assert six.PY2 or TF_version >= (1, 10), \
+                assert TF_version >= (1, 10), \
                     "Cross-GPU BatchNorm is only supported in TF>=1.10 ." \
                     "Upgrade TF or apply this patch manually: https://github.com/tensorflow/tensorflow/pull/20360"
 

tensorpack/predict/base.py

@@ -71,7 +71,6 @@ class AsyncPredictorBase(PredictorBase):
         """ Start workers """
 
     def _do_call(self, dp):
-        assert six.PY3, "With Python2, sync methods not available for async predictor"
         fut = self.put_task(dp)
         # in Tornado, Future.result() doesn't wait
         return fut.result()

tensorpack/predict/concurrency.py

@@ -4,7 +4,7 @@
 
 import multiprocessing
 import numpy as np
-import six
+from concurrent.futures import Future
 import tensorflow as tf
 from six.moves import queue, range
 
@@ -154,12 +154,6 @@ class MultiThreadAsyncPredictor(AsyncPredictorBase):
                 self.input_queue, f, id, batch_size=batch_size)
             for id, f in enumerate(predictors)]
 
-        if six.PY2:
-            # TODO XXX set logging here to avoid affecting TF logging
-            import tornado.options as options
-            options.parse_command_line(['--logging=debug'])
-            logger.warn("MultiThreadAsyncPredictor is inefficient in Python 2! Switch to Python 3 instead.")
-
     def start(self):
         if self._need_default_sess:
             assert tfv1.get_default_session() is not None, \
@@ -183,13 +177,3 @@ class MultiThreadAsyncPredictor(AsyncPredictorBase):
             f.add_done_callback(callback)
         self.input_queue.put((dp, f))
         return f
-
-
-try:
-    if six.PY2:
-        from tornado.concurrent import Future
-    else:
-        from concurrent.futures import Future
-except ImportError:
-    from ..utils.develop import create_dummy_class
-    MultiThreadAsyncPredictor = create_dummy_class('MultiThreadAsyncPredictor', 'tornado.concurrent')  # noqa

tensorpack/predict/dataset.py

@@ -6,7 +6,6 @@ import multiprocessing
 import os
 from abc import ABCMeta, abstractmethod
 import six
-from six.moves import range, zip
 
 from ..dataflow import DataFlow
 from ..dataflow.remote import dump_dataflow_to_process_queue

tensorpack/tfutils/gradproc.py

@@ -119,10 +119,7 @@ class MapGradient(GradientProcessor):
                 If it return None, the gradient is discarded (hence no update to the variable will happen).
             regex (str): used to match variables. Defaults to match all variables.
         """
-        if six.PY2:
-            args = inspect.getargspec(func).args
-        else:
-            args = inspect.getfullargspec(func).args
+        args = inspect.getfullargspec(func).args
         arg_num = len(args) - inspect.ismethod(func)
         assert arg_num in [1, 2], \
             "The function must take 1 or 2 arguments!  ({})".format(args)

tensorpack/tfutils/tower.py

@@ -5,8 +5,6 @@
 from abc import ABCMeta, abstractmethod, abstractproperty
 import six
 
-from six.moves import zip
-
 from ..compat import tfv1 as tf
 from ..utils import logger
 from ..utils.argtools import call_only_once

tensorpack/tfutils/unit_tests.py

-#-*- coding: utf-8 -*-
+# -*- coding: utf-8 -*-
 
-import six
 import unittest
 import tensorflow as tf
 
@@ -21,7 +20,6 @@ class ScopeUtilsTest(unittest.TestCase):
         with self.assertRaises(AssertionError):
             self._f()  # name conflict
 
-    @unittest.skipIf(six.PY2, "assertLogs not supported in Python 2")
     def test_under_name_scope_warning(self):
         x = tf.placeholder(tf.float32, [3])
         tf.nn.relu(x, name='s')

tensorpack/train/base.py

@@ -4,9 +4,7 @@
 import copy
 import time
 import weakref
-import six
 import tensorflow as tf
-from six.moves import range
 
 from ..compat import tfv1
 from ..callbacks import Callback, Callbacks, Monitors, MonitorBase
@@ -360,11 +358,10 @@ def _get_property(name):
     """
     ret = property(
         lambda self: getattr(self.loop, name))
-    if six.PY3:     # __doc__ is readonly in Py2
-        try:
-            ret.__doc__ = getattr(TrainLoop, name).__doc__
-        except AttributeError:
-            pass
+    try:
+        ret.__doc__ = getattr(TrainLoop, name).__doc__
+    except AttributeError:
+        pass
     return ret
 
 

tensorpack/utils/argtools.py

@@ -3,15 +3,10 @@
 
 
 import inspect
-import six
+import functools
 
 from . import logger
 
-if six.PY2:
-    import functools32 as functools
-else:
-    import functools
-
 __all__ = ['map_arg', 'memoized', 'memoized_method', 'graph_memoized', 'shape2d', 'shape4d',
            'memoized_ignoreargs', 'log_once']
 
@@ -26,13 +21,10 @@ def map_arg(**maps):
     def deco(func):
         @functools.wraps(func)
         def wrapper(*args, **kwargs):
-            if six.PY2:
-                argmap = inspect.getcallargs(func, *args, **kwargs)
-            else:
-                # getcallargs was deprecated since 3.5
-                sig = inspect.signature(func)
-                argmap = sig.bind_partial(*args, **kwargs).arguments
-            for k, map_func in six.iteritems(maps):
+            # getcallargs was deprecated since 3.5
+            sig = inspect.signature(func)
+            argmap = sig.bind_partial(*args, **kwargs).arguments
+            for k, map_func in maps.items():
                 if k in argmap:
                     argmap[k] = map_func(argmap[k])
             return func(**argmap)

tensorpack/utils/concurrency.py

@@ -14,15 +14,11 @@ import weakref
 from contextlib import contextmanager
 import six
 from six.moves import queue
+import subprocess
 
 from . import logger
 from .argtools import log_once
 
-if six.PY2:
-    import subprocess32 as subprocess
-else:
-    import subprocess
-
 
 __all__ = ['StoppableThread', 'LoopThread', 'ShareSessionThread',
            'ensure_proc_terminate',

tensorpack/utils/loadcaffe.py

@@ -127,18 +127,17 @@ def get_caffe_pb():
         download(CAFFE_PROTO_URL, dir)
         assert os.path.isfile(os.path.join(dir, 'caffe.proto'))
 
-        if sys.version_info.major == 3:
-            cmd = "protoc --version"
-            version, ret = subproc_call(cmd, timeout=3)
-            if ret != 0:
-                sys.exit(1)
-            try:
-                version = version.decode('utf-8')
-                version = float('.'.join(version.split(' ')[1].split('.')[:2]))
-                assert version >= 2.7, "Require protoc>=2.7 for Python3"
-            except Exception:
-                logger.exception("protoc --version gives: " + str(version))
-                raise
+        cmd = "protoc --version"
+        version, ret = subproc_call(cmd, timeout=3)
+        if ret != 0:
+            sys.exit(1)
+        try:
+            version = version.decode('utf-8')
+            version = float('.'.join(version.split(' ')[1].split('.')[:2]))
+            assert version >= 2.7, "Require protoc>=2.7 for Python3"
+        except Exception:
+            logger.exception("protoc --version gives: " + str(version))
+            raise
 
         cmd = 'cd {} && protoc caffe.proto --python_out .'.format(dir)
         ret = os.system(cmd)

tensorpack/utils/timer.py

@@ -5,15 +5,11 @@
 import atexit
 from collections import defaultdict
 from contextlib import contextmanager
-from time import time as timer
-import six
+from time import perf_counter as timer  # noqa
 
 from . import logger
 from .stats import StatCounter
 
-if six.PY3:
-    from time import perf_counter as timer  # noqa
-
 
 __all__ = ['timed_operation', 'IterSpeedCounter', 'Timer']
 
@@ -68,7 +64,7 @@ def print_total_timer():
     """
     if len(_TOTAL_TIMER_DATA) == 0:
         return
-    for k, v in six.iteritems(_TOTAL_TIMER_DATA):
+    for k, v in _TOTAL_TIMER_DATA.items():
         logger.info("Total Time: {} -> {:.2f} sec, {} times, {:.3g} sec/time".format(
             k, v.sum, v.count, v.average))