svn.andrew.net.au/usbspindownd/usbspindownd.py

#!/usr/bin/python
# vi:set ts=2:et:sw=2
#
# Daemon to monitor /proc/diskstats and spin down USB drives determined to be
# idle
#
# Author: Andrew Pollock <me@andrew.net.au>
# Copyright: (c) 2008 Andrew Pollock <me@andrew.net.au>
#

#
# Need a config file that contains the drives to watch and how long they must
# be idle for before spinning down
#
# Need to determine if sg_start is installed, and if so, where
#
# Need to monitor field 13 of /proc/diskstats for each drive. Value unchanged
# from last time means idle, value changed means not-idle and presumed spun-up
#
# Need to maintain a flag for when we've spun the drive down, so we don't keep
# spinning it down every time we think it's idle
#

import diskstats
import syslog
import optparse
import ConfigParser
import sys
import os
import time
import signal

spindown_cmd = ""
spindown_cmd_args = ""
keep_running = True
signals = {}

def signal_handler(signal, stack):
  global keep_running
  global sigdict
  keep_running = False


def getsignals():
  signals = {}
  for name in dir(signal):
    if name.startswith("SIG"):
      signals[getattr(signal, name)] = name
  return signals


def search_path(filename, search_path):
  file_found = False
  paths = search_path.split(os.pathsep)
  for path in paths:
    if os.path.exists(os.path.join(path, filename)):
      file_found = True
      break
  if file_found:
    return os.path.abspath(os.path.join(path, filename))
  else:
    return None


def debug(options, message):
  if options.debug:
    print "%s: %s" % (time.asctime(time.localtime()), message)


def log(message):
  pass


def load_config(options):
  global spindown_cmd, spindown_cmd_args
  cf = ConfigParser.SafeConfigParser()
  try:
    debug(options, "Attempting to read %s" % options.config)
    cf.readfp(open(options.config))
  except IOError, e:
    print "Got a '%s' trying to read %s" % (e.strerror, options.config)
    sys.exit(1)
  if cf.has_option("DEFAULT", "wait"):
    defaultwait = cf.get("DEFAULT", "wait")
  else:
    defaultwait = 600;
  config = {}
  # TODO: Need to deal with a malformed config file here
  for disk in cf.defaults()['disks'].split(","):
    if cf.has_option(disk, "wait"):
      wait = cf.get(disk, "wait")
    else:
      wait = defaultwait
    config[disk] = { 'wait': wait, 'last_msio': 0, 'spun_down': False, 'timestamp': 0 }
  if cf.has_option("DEFAULT", "spindown_cmd"):
    spindown_cmd = cf.get("DEFAULT", "spindown_cmd")
    if cf.has_option("DEFAULT", "spindown_cmd_args"):
      spindown_cmd_args = cf.get("DEFAULT", "spindown_cmd_args")
  if not spindown_cmd:
    # Try searching for sg_start
    spindown_cmd = search_path("sg_start", os.getenv("PATH"))
    if spindown_cmd:
      spindown_cmd_args = "--stop --pc=2"
    else:
      # We couldn't find anything to spin down the disks
      print "No disk spinning down command specified or found in $PATH"
      sys.exit(1)
  debug(options, "Configuration loaded:")
  debug(options, "spindown_cmd: %s" % (spindown_cmd))
  debug(options, "spindown_cmd_args: %s" % (spindown_cmd_args))
  if options.debug:
    for disk in config:
      debug(options, "%s: %s" % (disk, config[disk]))
  return config
      

def spin_down(options, disk):
  if not options.noop:
    if spindown_cmd_args:
      return os.system("%s %s %s" % (spindown_cmd, spindown_cmd_args, disk)) >> 8
    else:
      return os.system("%s %s" % (spindown_cmd, disk)) >> 8
  else:
    debug(options, "Not really spinning down the disk")
    return 0


def monitor_disks(config, options):
  global keep_running
  debug(options, "Monitoring disks")
  while keep_running:
    for disk in config:
      debug(options, "Considering %s" % (disk))
      ds = diskstats.DiskStats(disk)
      msio = None
      try:
        msio = ds.diskstat("msio")
      except diskstats.Error, e:
        # This disk doesn't exist at this time
        debug(options, "%s is not present" % (disk))
        continue
      if config[disk]["last_msio"] == 0:
        debug(options, "First time we've considered this disk")
        config[disk]["last_msio"] = msio
        config[disk]["timestamp"] = int(time.time())
      else:
        if msio == config[disk]["last_msio"]:
          debug(options, "Disk has been idle since last considered")
          now = int(time.time())
          if (now - config[disk]["timestamp"]) >= config[disk]["wait"]:
            debug(options, "Disk eligible for spinning down")
            # We can spin this disk down
            if not config[disk]["spun_down"]:
              if spin_down(disk):
                debug(options, "Disk spun down")
                config[disk]["spun_down"] = True
              else:
                raise Error("Failed to spin down %s" % disk)
            else:
              debug(options, "Disk already spun down")
          else:
            # This disk is ineligible for spinning down at this time
            debug(options, "Disk idle for %s seconds, but not for long enough (%s)" % (now - config[disk]["timestamp"], config[disk]["wait"]))
        else:
          debug(options, "Disk not idle (old msio: %s, current msio: %s)" % (config[disk]["last_msio"], msio))
          config[disk]["last_msio"] = msio
          config[disk]["timestamp"] = int(time.time())
          config[disk]["spun_down"] = False
    debug(options, "Sleeping")
    time.sleep(60)
  debug(options, "Shutting down")

def main():
  global options
  global signals
  signals = getsignals()
  signal.signal(signal.SIGTERM, signal_handler)
  signal.signal(signal.SIGINT, signal_handler)
  parser = optparse.OptionParser()
  parser.add_option("-n", "--dry-run", 
    action="store_true",
    dest="noop",
    default=False,
    help="Don't do anything, just log what would be done")
  parser.add_option("-c", "--config",
    action="store",
    dest="config",
    default="/etc/usbspindownd.conf",
    help="Configuration file for usbspindownd")
  parser.add_option("-d", "--debug",
    action="store_true",
    dest="debug",
    default=False,
    help="Turn on extra debugging")
  (options, args) = parser.parse_args()

  config = load_config(options)
  monitor_disks(config, options)

if __name__ == "__main__":
  main()
1	apollock	29	#!/usr/bin/python
2	apollock	30	# vi:set ts=2:et:sw=2
3	apollock	29	#
4			# Daemon to monitor /proc/diskstats and spin down USB drives determined to be
5			# idle
6			#
7			# Author: Andrew Pollock <me@andrew.net.au>
8			# Copyright: (c) 2008 Andrew Pollock <me@andrew.net.au>
9			#
10
11			#
12			# Need a config file that contains the drives to watch and how long they must
13			# be idle for before spinning down
14			#
15			# Need to determine if sg_start is installed, and if so, where
16			#
17			# Need to monitor field 13 of /proc/diskstats for each drive. Value unchanged
18			# from last time means idle, value changed means not-idle and presumed spun-up
19			#
20			# Need to maintain a flag for when we've spun the drive down, so we don't keep
21			# spinning it down every time we think it's idle
22			#
23
24	apollock	30	import diskstats
25			import syslog
26			import optparse
27			import ConfigParser
28			import sys
29			import os
30			import time
31	apollock	33	import signal
32	apollock	30
33			spindown_cmd = ""
34			spindown_cmd_args = ""
35	apollock	33	keep_running = True
36			signals = {}
37	apollock	30
38	apollock	33	def signal_handler(signal, stack):
39			global keep_running
40			global sigdict
41			keep_running = False
42	apollock	30
43	apollock	33
44			def getsignals():
45			signals = {}
46			for name in dir(signal):
47			if name.startswith("SIG"):
48			signals[getattr(signal, name)] = name
49			return signals
50
51
52	apollock	30	def search_path(filename, search_path):
53			file_found = False
54			paths = search_path.split(os.pathsep)
55			for path in paths:
56			if os.path.exists(os.path.join(path, filename)):
57			file_found = True
58			break
59			if file_found:
60			return os.path.abspath(os.path.join(path, filename))
61			else:
62			return None
63
64
65			def debug(options, message):
66			if options.debug:
67			print "%s: %s" % (time.asctime(time.localtime()), message)
68
69	apollock	33
70			def log(message):
71			pass
72
73
74	apollock	30	def load_config(options):
75			global spindown_cmd, spindown_cmd_args
76			cf = ConfigParser.SafeConfigParser()
77			try:
78			debug(options, "Attempting to read %s" % options.config)
79			cf.readfp(open(options.config))
80			except IOError, e:
81			print "Got a '%s' trying to read %s" % (e.strerror, options.config)
82			sys.exit(1)
83			if cf.has_option("DEFAULT", "wait"):
84			defaultwait = cf.get("DEFAULT", "wait")
85			else:
86			defaultwait = 600;
87			config = {}
88			# TODO: Need to deal with a malformed config file here
89			for disk in cf.defaults()['disks'].split(","):
90			if cf.has_option(disk, "wait"):
91			wait = cf.get(disk, "wait")
92			else:
93			wait = defaultwait
94			config[disk] = { 'wait': wait, 'last_msio': 0, 'spun_down': False, 'timestamp': 0 }
95			if cf.has_option("DEFAULT", "spindown_cmd"):
96			spindown_cmd = cf.get("DEFAULT", "spindown_cmd")
97			if cf.has_option("DEFAULT", "spindown_cmd_args"):
98			spindown_cmd_args = cf.get("DEFAULT", "spindown_cmd_args")
99			if not spindown_cmd:
100			# Try searching for sg_start
101			spindown_cmd = search_path("sg_start", os.getenv("PATH"))
102			if spindown_cmd:
103			spindown_cmd_args = "--stop --pc=2"
104			else:
105			# We couldn't find anything to spin down the disks
106			print "No disk spinning down command specified or found in $PATH"
107			sys.exit(1)
108			debug(options, "Configuration loaded:")
109			debug(options, "spindown_cmd: %s" % (spindown_cmd))
110			debug(options, "spindown_cmd_args: %s" % (spindown_cmd_args))
111			if options.debug:
112			for disk in config:
113			debug(options, "%s: %s" % (disk, config[disk]))
114			return config
115
116
117			def spin_down(options, disk):
118			if not options.noop:
119			if spindown_cmd_args:
120			return os.system("%s %s %s" % (spindown_cmd, spindown_cmd_args, disk)) >> 8
121			else:
122			return os.system("%s %s" % (spindown_cmd, disk)) >> 8
123			else:
124			debug(options, "Not really spinning down the disk")
125			return 0
126
127
128			def monitor_disks(config, options):
129	apollock	33	global keep_running
130	apollock	30	debug(options, "Monitoring disks")
131	apollock	33	while keep_running:
132	apollock	30	for disk in config:
133			debug(options, "Considering %s" % (disk))
134			ds = diskstats.DiskStats(disk)
135			msio = None
136			try:
137			msio = ds.diskstat("msio")
138			except diskstats.Error, e:
139			# This disk doesn't exist at this time
140			debug(options, "%s is not present" % (disk))
141			continue
142			if config[disk]["last_msio"] == 0:
143			debug(options, "First time we've considered this disk")
144			config[disk]["last_msio"] = msio
145			config[disk]["timestamp"] = int(time.time())
146			else:
147			if msio == config[disk]["last_msio"]:
148			debug(options, "Disk has been idle since last considered")
149			now = int(time.time())
150			if (now - config[disk]["timestamp"]) >= config[disk]["wait"]:
151			debug(options, "Disk eligible for spinning down")
152			# We can spin this disk down
153			if not config[disk]["spun_down"]:
154			if spin_down(disk):
155			debug(options, "Disk spun down")
156			config[disk]["spun_down"] = True
157			else:
158			raise Error("Failed to spin down %s" % disk)
159			else:
160			debug(options, "Disk already spun down")
161			else:
162			# This disk is ineligible for spinning down at this time
163	apollock	31	debug(options, "Disk idle for %s seconds, but not for long enough (%s)" % (now - config[disk]["timestamp"], config[disk]["wait"]))
164	apollock	30	else:
165			debug(options, "Disk not idle (old msio: %s, current msio: %s)" % (config[disk]["last_msio"], msio))
166			config[disk]["last_msio"] = msio
167			config[disk]["timestamp"] = int(time.time())
168			config[disk]["spun_down"] = False
169			debug(options, "Sleeping")
170			time.sleep(60)
171	apollock	33	debug(options, "Shutting down")
172	apollock	30
173	apollock	29	def main():
174	apollock	33	global options
175			global signals
176			signals = getsignals()
177			signal.signal(signal.SIGTERM, signal_handler)
178			signal.signal(signal.SIGINT, signal_handler)
179	apollock	30	parser = optparse.OptionParser()
180			parser.add_option("-n", "--dry-run",
181			action="store_true",
182			dest="noop",
183			default=False,
184			help="Don't do anything, just log what would be done")
185			parser.add_option("-c", "--config",
186			action="store",
187			dest="config",
188			default="/etc/usbspindownd.conf",
189			help="Configuration file for usbspindownd")
190			parser.add_option("-d", "--debug",
191			action="store_true",
192			dest="debug",
193			default=False,
194			help="Turn on extra debugging")
195			(options, args) = parser.parse_args()
196	apollock	29
197	apollock	30	config = load_config(options)
198			monitor_disks(config, options)
199
200	apollock	29	if __name__ == "__main__":
201	apollock	30	main()