def write_json():
  """Generate all json files.
  """
  from dcmetrometrics.common.JSONifier import JSONWriter
  import os

  jwriter = JSONWriter(WWW_DIR)
  # jwriter = JSONWriter(basedir = os.path.join('client', 'app'))

  from dcmetrometrics.eles.models import Unit
  num_units = Unit.objects.no_cache().count()
  for i, unit in enumerate(Unit.objects.no_cache()):
    logger.info('Writing unit %i of %i: %s'%(i, num_units, unit.unit_id))
    jwriter.write_unit(unit)

  # Write the station directory
  jwriter.write_station_directory()

  # Write the recent updates
  jwriter.write_recent_updates()  

  for report in SystemServiceReport.objects.no_cache():
    logger.info("Writing system service report for day %s"%report.day)
    jwriter.write_daily_system_service_report(report = report)


  elapsed = (datetime.now() - start).total_seconds()
  print "%.2f seconds elapsed"%elapsed