df-check

#!/usr/bin/python3
#
# Sends email about disks getting full.  Run nightly.
# Needs no special privileges.
#
# Assumptions: Linux, Python 3, mailx.
#

import sys
import os
import math
import subprocess


def usage():
  m = '''Usage: df-check [-n] [-t]'''
  print(m)

###############################################################################

class dfcheck_t:

  addr = 'name@example.com'
  subject = 'DISK FULL ALERT'
  filePct = 95
  blockPct = 95
  passGigs = 100
  units = 'bkMGTPEZY'

  def __init__(self):
    self.header = None
    self.msgs = []
    self.sendmail = True
    self.test = False
    un = os.uname()
    self.host = un.nodename


  def run(self):
    try:
      overs = self.findOvers()
      if self.msgs:
        self.notify()
    except Exception as ex:
      print(ex)
      return -1
    return 0


  def findOvers(self):
    for part in self.getParts():
      self.checkPart(part)


  def notify(self):
    msg = 'Host: %s\n\n' % self.host
    if self.header:
      msg += self.header + '\n'
    msg += '\n'.join(self.msgs) + '\n'
    if not self.sendmail:
      print(msg)
      return
    subj = self.subject + ' ' + self.host
    args = ['/usr/bin/mailx', '-s', subj, self.addr]
    res = subprocess.Popen(args,
      stdin = subprocess.PIPE,
      stdout = subprocess.DEVNULL,
      stderr = subprocess.DEVNULL)
    res.stdin.write(msg.encode('utf-8'))
    res.stdin.close()
    res.wait()


  def getParts(self):
    rv = []
    fil = open('/proc/mounts')
    for lin in fil:
      exp = lin.split()
      if exp[0].startswith('/'):
        rv.append(exp[1])
    fil.close()
    return rv


  def checkPart(self, pth):
    # do not match df output, because ordinary users can't use all 100%
    rec = os.statvfs(pth)
    bpct = math.ceil(100.0 * (rec.f_blocks - rec.f_bavail) / rec.f_blocks)
    fpct = math.ceil(100.0 * (rec.f_files - rec.f_favail) / rec.f_files)
    blkPerGig = 1024.0 * 1024.0 * 1024.0 / rec.f_bsize
    availGigs = rec.f_bavail / blkPerGig

    emit = self.test
    if fpct >= self.filePct:
      emit = True
    elif (bpct >= self.blockPct) and (availGigs < self.passGigs):
      emit = True

    if emit:
      val = self.fmt(rec.f_bavail, rec.f_bsize)
      self.header =  'Block  Inode  BkAvail  Mountpoint'
      msg = (':%3d%%   %3d%%  %s  %s' %
             (bpct, fpct, val, pth))
      self.msgs.append(msg)


  def fmt(self, blocks, bsize):
    bytes = float(blocks) * bsize
    cnt = 0
    while bytes > 1024.0:
      cnt += 1
      bytes /= 1024.0
    return '%6.1f%c' % (bytes, self.units[cnt])

###############################################################################

def main(args = None):
  if args is None:
    args = sys.argv[1:]

  dfc = dfcheck_t()

  try:
    while args and args[0].startswith('-'):
      arg = args.pop(0)
      if arg == '-n':
        dfc.sendmail = False
      elif arg == '-t':
        dfc.test = True
      else:
        raise RuntimeError('unknown option ' + arg)

    if args:
      raise RuntimeError('too many arguments')

  except Exception as ex:
    usage()
    print(ex)
    return 1

  res = dfc.run()
  if res < 0:
    return 1
  return 0


if __name__ == "__main__":
  sys.exit(main())

###############################################################################
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