text: 
  const fs = require('fs');
  const path = require('path');
  
  module.exports.handler = function (request, response, context) {
    
      const root = process.env['ROOT_DIR'];
  
      var file = 'test_http.txt';
  
      console.log("# read dir is : " + fs.readdirSync(root));
      console.log("path.join(root, file): " + path.join(root, file));
  
      var contents = fs.readFileSync(path.join(root, file), 'utf8');
      
      const res = {
          file,
          contents,
          message: "read success"
      };
  
      response.setStatusCode(200)
      response.setHeader('content-type', 'application/json');
      response.send(JSON.stringify(res));
  }