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import os
import sys
import time
import signal
import logging
import uuid
import xml.etree.ElementTree as XET
from subprocess import PIPE
from resource import Popen, FILE, GLUSTER, SSH
from threading import Lock
from gconf import gconf
from syncdutils import update_file, select, waitpid, set_term_handler, is_host_local, GsyncdError
from syncdutils import escape, Thread, finalize, memoize
class Volinfo(object):
def __init__(self, vol, host='localhost', prelude=[]):
po = Popen(prelude + ['gluster', '--xml', '--remote-host=' + host, 'volume', 'info', vol],
stdout=PIPE, stderr=PIPE)
vix = po.stdout.read()
po.wait()
po.terminate_geterr()
vi = XET.fromstring(vix)
if vi.find('opRet').text != '0':
if prelude:
via = '(via %s) ' % prelude.join(' ')
else:
via = ' '
raise GsyncdError('getting volume info of %s%s failed with errorcode %s',
(vol, via, vi.find('opErrno').text))
self.tree = vi
self.volume = vol
self.host = host
def get(self, elem):
return self.tree.findall('.//' + elem)
@property
@memoize
def bricks(self):
def bparse(b):
host, dirp = b.text.split(':', 2)
return {'host': host, 'dir': dirp}
return [ bparse(b) for b in self.get('brick') ]
@property
@memoize
def uuid(self):
ids = self.get('id')
if len(ids) != 1:
raise GsyncdError("volume info of %s obtained from %s: ambiguous uuid",
self.volume, self.host)
return ids[0].text
class Monitor(object):
"""class which spawns and manages gsyncd workers"""
ST_INIT = 'Initializing...'
ST_STABLE = 'Stable'
ST_FAULTY = 'faulty'
ST_INCON = 'inconsistent'
_ST_ORD = [ST_STABLE, ST_INIT, ST_FAULTY, ST_INCON]
def __init__(self):
self.lock = Lock()
self.state = {}
def set_state(self, state, w=None):
"""set the state that can be used by external agents
like glusterd for status reporting"""
computestate = lambda: self.state and self._ST_ORD[max(self._ST_ORD.index(s) for s in self.state.values())]
if w:
self.lock.acquire()
old_state = computestate()
self.state[w] = state
state = computestate()
self.lock.release()
if state != old_state:
self.set_state(state)
else:
logging.info('new state: %s' % state)
if getattr(gconf, 'state_file', None):
update_file(gconf.state_file, lambda f: f.write(state + '\n'))
@staticmethod
def terminate():
# relax one SIGTERM by setting a handler that sets back
# standard handler
set_term_handler(lambda *a: set_term_handler())
# give a chance to graceful exit
os.kill(-os.getpid(), signal.SIGTERM)
def monitor(self, w, argv, cpids):
"""the monitor loop
Basic logic is a blantantly simple blunt heuristics:
if spawned client survives 60 secs, it's considered OK.
This servers us pretty well as it's not vulneralbe to
any kind of irregular behavior of the child...
... well, except for one: if children is hung up on
waiting for some event, it can survive aeons, still
will be defunct. So we tweak the above logic to
expect the worker to send us a signal within 60 secs
(in the form of closing its end of a pipe). The worker
does this when it's done with the setup stage
ready to enter the service loop (note it's the setup
stage which is vulnerable to hangs -- the full
blown worker blows up on EPIPE if the net goes down,
due to the keep-alive thread)
"""
self.set_state(self.ST_INIT, w)
ret = 0
def nwait(p, o=0):
p2, r = waitpid(p, o)
if not p2:
return
return r
def exit_signalled(s):
""" child teminated due to receipt of SIGUSR1 """
return (os.WIFSIGNALED(s) and (os.WTERMSIG(s) == signal.SIGUSR1))
def exit_status(s):
if os.WIFEXITED(s):
return os.WEXITSTATUS(s)
return 1
conn_timeout = int(gconf.connection_timeout)
while ret in (0, 1):
logging.info('-' * conn_timeout)
logging.info('starting gsyncd worker')
pr, pw = os.pipe()
cpid = os.fork()
if cpid == 0:
os.close(pr)
os.execv(sys.executable, argv + ['--feedback-fd', str(pw),
'--local-path', w[0],
'--local-id', '.' + escape(w[0]),
'--resource-remote', w[1]])
self.lock.acquire()
cpids.add(cpid)
self.lock.release()
os.close(pw)
t0 = time.time()
so = select((pr,), (), (), conn_timeout)[0]
os.close(pr)
if so:
ret = nwait(cpid, os.WNOHANG)
if ret != None:
logging.info("worker(%s) died before establishing " \
"connection" % w[0])
else:
logging.debug("worker(%s) connected" % w[0])
while time.time() < t0 + conn_timeout:
ret = nwait(cpid, os.WNOHANG)
if ret != None:
logging.info("worker(%s) died in startup " \
"phase" % w[0])
break
time.sleep(1)
else:
logging.info("worker(%s) not confirmed in %d sec, " \
"aborting it" % (w[0], conn_timeout))
os.kill(cpid, signal.SIGKILL)
ret = nwait(cpid)
if ret == None:
self.set_state(self.ST_STABLE, w)
ret = nwait(cpid)
if exit_signalled(ret):
ret = 0
else:
ret = exit_status(ret)
if ret in (0,1):
self.set_state(self.ST_FAULTY, w)
time.sleep(10)
self.set_state(self.ST_INCON, w)
return ret
def multiplex(self, wspx, suuid):
argv = sys.argv[:]
for o in ('-N', '--no-daemon', '--monitor'):
while o in argv:
argv.remove(o)
argv.extend(('-N', '-p', '', '--slave-id', suuid))
argv.insert(0, os.path.basename(sys.executable))
cpids = set()
ta = []
for wx in wspx:
def wmon(w):
cpid, _ = self.monitor(w, argv, cpids)
time.sleep(1)
self.lock.acquire()
for cpid in cpids:
os.kill(cpid, signal.SIGKILL)
self.lock.release()
finalize(exval=1)
t = Thread(target = wmon, args=[wx])
t.start()
ta.append(t)
for t in ta:
t.join()
def distribute(*resources):
master, slave = resources
mvol = Volinfo(master.volume, master.host)
logging.debug('master bricks: ' + repr(mvol.bricks))
prelude = []
si = slave
if isinstance(slave, SSH):
prelude = gconf.ssh_command.split() + [slave.remote_addr]
si = slave.inner_rsc
logging.debug('slave SSH gateway: ' + slave.remote_addr)
if isinstance(si, FILE):
sbricks = {'host': 'localhost', 'dir': si.path}
suuid = uuid.uuid5(uuid.NAMESPACE_URL, slave.get_url(canonical=True))
elif isinstance(si, GLUSTER):
svol = Volinfo(si.volume, si.host, prelude)
sbricks = svol.bricks
suuid = svol.uuid
else:
raise GsyncdError("unkown slave type " + slave.url)
logging.info('slave bricks: ' + repr(sbricks))
if isinstance(si, FILE):
slaves = [ slave.url ]
else:
slavenodes = set(b['host'] for b in sbricks)
if isinstance(slave, SSH) and not gconf.isolated_slave:
rap = SSH.parse_ssh_address(slave)
slaves = [ 'ssh://' + rap['user'] + '@' + h + ':' + si.url for h in slavenodes ]
else:
slavevols = [ h + ':' + si.volume for h in slavenodes ]
if isinstance(slave, SSH):
slaves = [ 'ssh://' + rap.remote_addr + ':' + v for v in slavevols ]
else:
slaves = slavevols
workerspex = [ (brick['dir'], slaves[idx % len(slaves)]) for idx, brick in enumerate(mvol.bricks) if is_host_local(brick['host']) ]
logging.info('worker specs: ' + repr(workerspex))
return workerspex, suuid
def monitor(*resources):
"""oh yeah, actually Monitor is used as singleton, too"""
return Monitor().multiplex(*distribute(*resources))
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