tools: regularize pip/venv for format_python_tools.py. (#8176)

As well as being a nice cleanup, this fixes some issues I had with local
Docker use of fix_format as a non-root user.

Signed-off-by: Harvey Tuch <htuch@google.com>

tools/format_python_tools.py

@@ -39,7 +39,7 @@ def validateFormat(fix=False):
   successful_update_files = set()
   for python_file in collectFiles():
     reformatted_source, encoding, changed = FormatFile(python_file,
-                                                       style_config='.style.yapf',
+                                                       style_config='tools/.style.yapf',
                                                        in_place=fix,
                                                        print_diff=not fix)
     if not fix:

tools/format_python_tools.sh

@@ -1,19 +1,11 @@
 #!/bin/bash
 
-set -e
-
-VENV_DIR="pyformat"
-SCRIPTPATH=$(realpath "$(dirname $0)")
-. $SCRIPTPATH/shell_utils.sh
-cd "$SCRIPTPATH"
+. tools/shell_utils.sh
 
-source_venv "$VENV_DIR"
-echo "Installing requirements..."
-pip3 -q install --upgrade pip
-pip3 -q install -r requirements.txt
+set -e
 
 echo "Running Python format check..."
-python3 format_python_tools.py $1
+python_venv format_python_tools $1
 
 echo "Running Python3 flake8 check..."
 python3 -m flake8 --version

tools/shell_utils.sh

@@ -1,6 +1,6 @@
 source_venv() {
   VENV_DIR=$1
-  if [[ "$VIRTUAL_ENV" == "" ]]; then
+  if [[ "${VIRTUAL_ENV}" == "" ]]; then
     if [[ ! -d "${VENV_DIR}"/venv ]]; then
       virtualenv "${VENV_DIR}"/venv --no-site-packages --python=python3
     fi
@@ -14,10 +14,12 @@ python_venv() {
   SCRIPT_DIR=$(realpath "$(dirname "$0")")
 
   BUILD_DIR=build_tools
-  VENV_DIR="$BUILD_DIR/$1"
+  PY_NAME="$1"
+  VENV_DIR="${BUILD_DIR}/${PY_NAME}"
 
-  source_venv "$VENV_DIR"
+  source_venv "${VENV_DIR}"
   pip install -r "${SCRIPT_DIR}"/requirements.txt
 
-  python3 "${SCRIPT_DIR}/$1.py" $*
+  shift
+  python3 "${SCRIPT_DIR}/${PY_NAME}.py" $*
 }