py/instalog/plugins/input_health.py

#!/usr/bin/python2
#
# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Input health plugin.

Logs system information about the machine to monitor its health.
"""

from __future__ import print_function

import datetime
import os

import instalog_common  # pylint: disable=unused-import
from instalog import datatypes
from instalog import plugin_base
from instalog.utils.arg_utils import Arg


_DEFAULT_INTERVAL = 20


class InputHealth(plugin_base.InputPlugin):

  ARGS = [
      Arg('interval', (int, float), 'Interval in between health events.',
          default=_DEFAULT_INTERVAL),
  ]

  @staticmethod
  def GetDiskUsage(path):
    st = os.statvfs(path)
    free = st.f_bavail * st.f_frsize
    total = st.f_blocks * st.f_frsize
    used = (st.f_blocks - st.f_bfree) * st.f_frsize
    return {
        'total': total,
        'used': used,
        'free': free
    }

  def Main(self):
    """Main thread of the plugin."""
    # Check to make sure plugin should still be running.
    while not self.IsStopping():
      # Data for the event.
      data = {
          '__health__': True,
          'systemTime': datetime.datetime.utcnow(),
          'diskUsage': self.GetDiskUsage(self.GetDataDir())
      }

      # Create the event.
      health_event = datatypes.Event(data, {})

      self.info('Emitting health event')
      if not self.Emit([health_event]):
        self.error('Failed to emit health event, dropping')
        # TODO(kitching): Find a better way to block the plugin when we are in
        #                 one of the PAUSING, PAUSED, or UNPAUSING states.
        self.Sleep(1)

      # Sleep until next emit interval.
      self.debug('Sleeping for %s', self.args.interval)
      self.Sleep(self.args.interval)


if __name__ == '__main__':
  plugin_base.main()