Run flake8 on Python instead of legacy Python (#7388)

Blocked by: #7383, #7384, and #7385

Related to: #4552 #7322 

Signed-off-by: cclauss cclauss@me.com

Also adds more critical flake8 tests.

Signed-off-by: cclauss <cclauss@me.com>

tools/deprecate_features/deprecate_features.py

@@ -4,6 +4,7 @@
 import re
 import subprocess
 import fileinput
+from six.moves import input
 
 
 # Sorts out the list of deprecated proto fields which should be disallowed and returns a tuple of
@@ -89,7 +90,7 @@ def flip_runtime_features():
 print('\n\nSuggested envoy-announce email: \n')
 print(email)
 
-if not raw_input('Apply relevant runtime changes? [yN] ').strip().lower() in ('y', 'yes'):
+if not input('Apply relevant runtime changes? [yN] ').strip().lower() in ('y', 'yes'):
   exit(1)
 
 for line in fileinput.FileInput('source/common/runtime/runtime_features.cc', inplace=1):

tools/format_python_tools.sh

@@ -9,10 +9,12 @@ cd "$SCRIPTPATH"
 
 source_venv "$VENV_DIR"
 echo "Installing requirements..."
-pip install -r requirements.txt
+pip3 install --upgrade pip
+pip3 install -r requirements.txt
 
 echo "Running Python format check..."
-python format_python_tools.py $1
+python3 format_python_tools.py $1
 
 echo "Running Python3 flake8 check..."
-flake8 . --exclude=*/venv/* --count --select=E901,E999,F821,F822,F823 --show-source --statistics
+python3 -m flake8 --version
+python3 -m flake8 . --exclude=*/venv/* --count --select=E9,F63,F72,F82 --show-source --statistics

tools/requirements.txt

@@ -1,2 +1,2 @@
-flake8==3.6.0
+flake8==3.7.7
 yapf==0.25.0

tools/shell_utils.sh

@@ -2,7 +2,7 @@ source_venv() {
   VENV_DIR=$1
   if [[ "$VIRTUAL_ENV" == "" ]]; then
     if [[ ! -d "${VENV_DIR}"/venv ]]; then
-      virtualenv "${VENV_DIR}"/venv --no-site-packages --python=python2.7
+      virtualenv "${VENV_DIR}"/venv --no-site-packages --python=python3.5
     fi
     source "${VENV_DIR}"/venv/bin/activate
   else