logger.html

<script>
/***************************************************************************
*
*  Copyright 2020 Google Inc.
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*      https://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*  Note that these code samples being shared are not official Google
*  products and are not formally supported.
*
***************************************************************************/

/**
 * Module that contains logger that outputs logging statements from the server
 * side into the Log tab
 */

// Global logger singleton instance
var logger;

/**
 * Logger
 */
var Logger = function() {
  var offset = 0;

  /**
   * Clears and resets the log, returns a promise
   *
   * returns: Promise
   */
  this.clear = function() {
    offset = 0;

    return new Runner().run('clear', [{'sheetName': 'Log', 'range': 'A1:B'}]);
  }

  /**
   * Counts how many log lines are in the jobs
   *
   * params:
   *  jobs: list of jobs
   *
   * returns: Number of log lines in all jobs
   */
  function countLogLines(jobs) {
    var result = 0;

    for(var i = 0; i < jobs.length; i++) {
      var job = jobs[i];

      if(job.logs) {
        result += jobs[i].logs.length;
      }
    }

    return result;
  }

  /**
   * Writes logs from jobs to log sheet
   *
   * params:
   *   jobs: list of jobs
   */
  this.log = function(jobs) {
    forEach(jobs, function(index, job) {
      if(job.error) {
        if(!job.logs) {
          job.logs = [];
        }
        job.logs.push([new Date(), job.error]);
      }
    });

    var job = {
      'jobs': jobs,
      'offset': offset
    }

    offset += countLogLines(jobs);

    return new Runner().run('writeLogs', [job]).then(function(result) {
      if(result.length > 0) {
        var job = result[0];

        return job.jobs;
      }

      return null;
    });
  }
}

/**
 * Use this function to get the singleton logger instance
 */
function getLogger() {
  if(!logger) {
    logger = new Logger();
  }

  return logger;
}
</script>