Python virtualenv exec helper like npx in NodeJS world.

pyx

#!/bin/bash

function log() {
  ts=$(date +%Y-%m-%d_%T,%6N)
  level=$1
  shift 1
  case $level in
  (err*)
    echo ${ts} [ERROR]: $* 1>&2
    ;;
  (info*)
    echo ${ts} [INFO]: $*
    ;;
  (debug*)
    echo ${ts} [DEBUG] $*
    ;;
  (*)
    echo ${ts} [${level}] $* 1>&2
    ;;
  esac
}

function find_venv() {
  if [[ -d "local" && -x "local/bin/python" ]]; then
    echo "local"
  fi
  if [[ -d ".virtualenv" && -x ".virtualenv/bin/python" ]]; then
    echo ".virtualenv"
  fi
  if [[ -d ".venv" && -x ".venv/bin/python" ]]; then
    echo ".venv"
  fi
}

if [[ -z $1 ]]; then
  echo "usage: pyx <command> [args...]"
  exit 1
fi

venv=$(find_venv)
if [[ -z ${venv} ]]; then
  log warn "cannot find any virtualenv!"
  exec $@
else
  log info "using virtualenv at \"${venv}\""
  bin=${venv}/bin/${1}
  if [[ -x ${bin} ]]; then
    log info "found executable \"${bin}\""
    shift 1
    exec ${bin} $@
  fi
fi