generate `*_pb*.py` with bazel and copy to project

gen_pb.sh

#!/usr/bin/env bash

function info () {
  printf "\r  \033[00;34m>>>\033[0m %s \n" "$1"
}

function remove_old() {
  info "Remove all previous generated files!"
  local VERBOSE="$1"
  if [ -z "$VERBOSE" ]
  then
    find . -iname "*_pb2*.py" -delete;
  else
    find . -iname "*_pb2*.py" -exec rm "${VERBOSE}" -f {} \;
  fi
}

function bazel_gen() {
  TARGET_LABEL=$1

  info "Run bazel target!"
  bazel build "${TARGET_LABEL}"
}

function list_py() {
  local TAR_PATH="$1"

  tar tf "${TAR_PATH}" \
    | grep -ve "\.\." \
    | grep _pb2
}

function extract_py() {
  local TAR_PATH="$1"
  local VERBOSE="$2"

  info "Extracting protobuf generated python files from ${TAR_PATH}"
  list_py "${TAR_PATH}" | xargs tar "${VERBOSE}" -xf "${TAR_PATH}"
}

function reduce_tar() {
  local TAR_PATH="$1"
  local REDUCED_TAR_PATH="$2"
  local VERBOSE="$3"
  local MANIFEST_FILE="bazel-bin/manifest.txt"

  info "Reduced tar with only protobuf generated python files from ${TAR_PATH}"
  list_py "${TAR_PATH}" > ${MANIFEST_FILE}
  < ${MANIFEST_FILE} xargs tar "${VERBOSE}" -xf "${TAR_PATH}"
  < ${MANIFEST_FILE} xargs tar "${VERBOSE}" -rf "${REDUCED_TAR_PATH}"
}

function usage() {
  cat <<-EOF
    ./gen_pb.sh [options]

    This small script did the following:
      * Remove all existing *.pb2.py or *.pb2_grpc.py files
      * Bazel build the ":proto_pkg" target
      * Extract all *.pb2.py or *.pb2_grpc.py to the current directory.

    In addition:
      * when --reduce is defined, pack all the extracted files into a tar, which reduce the tar size significantly
      * when --extract is defined, skip the first two steps and extract directly from provided tar
    Note that --reduce and --extract are mutually exclusive

    Options:
    -h --help:
        Show this help message
    -v --verbose:
        List removed files and extracted files when true
    -r --reduce REDUCED_TAR_PATH:
        Extract and save the protos to that TAR_PATH to reduce the size
    -e --extract SOURCE_TAR_PATH:
        No removal or bazel will be triggered, only extract from that TAR_PATH
	EOF
}

PROGRAM="${0##*/}"
GETOPT=$(command -v gnu-getopt || command -v getopt)

function main() {
  local VERBOSE=""
  local EXTRACT_ONLY=false
  local REDUCE_ONLY=false
  local TAR_PATH=""
  local REDUCED_TAR_PATH=""
  local PACKAGE_NAME=""
  local TARGET_NAME="proto_pkg"

  opts="$($GETOPT -o hve:r: -l help,verbose,extract:,reduce: -n "$PROGRAM" -- "$@")";
  eval set -- "$opts"

  while true;
  do
    case $1 in
      -h | --help)
        usage; exit 0;;
      -v | --verbose)
        VERBOSE="-v"
        shift;;
      -e | --extract)
        EXTRACT_ONLY=true
        shift;
        TAR_PATH=$1
        shift;;
      -r | --reduce)
        REDUCE_ONLY=true
        shift;
        REDUCED_TAR_PATH=$1
        shift;;
      --)
        shift;
        break;;
    esac
  done
  [ "$#" -gt 1 ] && usage && exit 1

  if [ -z "${TAR_PATH}" ]
  then
    [[ -z "${PACKAGE_NAME}" ]] \
      && TAR_PATH="bazel-bin/${TARGET_NAME}.tar" \
      || TAR_PATH="bazel-bin/${PACKAGE_NAME}/${TARGET_NAME}.tar"
  fi

  if [ "${EXTRACT_ONLY}" != "true" ];
  then
    remove_old ${VERBOSE}
    bazel_gen "//${PACKAGE_NAME}:${TARGET_NAME}"
  fi

  if [ "${REDUCE_ONLY}" == "true" ];
  then
    reduce_tar ${TAR_PATH} "${REDUCED_TAR_PATH}" ${VERBOSE}
  else
    extract_py ${TAR_PATH} ${VERBOSE}
  fi

  info "You are all set!"
}

main "$@"