import os import sys import time import stat import random import signal import json import logging import socket import string import errno from shutil import copyfileobj from errno import ENOENT, ENODATA, EPIPE, EEXIST from threading import currentThread, Condition, Lock from datetime import datetime from gconf import gconf from tempfile import mkdtemp, NamedTemporaryFile from syncdutils import FreeObject, Thread, GsyncdError, boolify, escape, \ unescape, select, gauxpfx, md5hex, selfkill, entry2pb, \ lstat, errno_wrap URXTIME = (-1, 0) # Utility functions to help us to get to closer proximity # of the DRY principle (no, don't look for elevated or # perspectivistic things here) def _xtime_now(): t = time.time() sec = int(t) nsec = int((t - sec) * 1000000) return (sec, nsec) def _volinfo_hook_relax_foreign(self): volinfo_sys = self.get_sys_volinfo() fgn_vi = volinfo_sys[self.KFGN] if fgn_vi: expiry = fgn_vi['timeout'] - int(time.time()) + 1 logging.info('foreign volume info found, waiting %d sec for expiry' % \ expiry) time.sleep(expiry) volinfo_sys = self.get_sys_volinfo() return volinfo_sys # The API! def gmaster_builder(excrawl=None): """produce the GMaster class variant corresponding to sync mode""" this = sys.modules[__name__] modemixin = gconf.special_sync_mode if not modemixin: modemixin = 'normal' changemixin = isinstance(excrawl, str) and excrawl or gconf.change_detector logging.info('setting up %s change detection mode' % changemixin) modemixin = getattr(this, modemixin.capitalize() + 'Mixin') crawlmixin = getattr(this, 'GMaster' + changemixin.capitalize() + 'Mixin') sendmarkmixin = boolify(gconf.use_rsync_xattrs) and SendmarkRsyncMixin or SendmarkNormalMixin purgemixin = boolify(gconf.ignore_deletes) and PurgeNoopMixin or PurgeNormalMixin class _GMaster(crawlmixin, modemixin, sendmarkmixin, purgemixin): pass return _GMaster # Mixin classes that implement the data format # and logic particularities of the certain # sync modes class NormalMixin(object): """normal geo-rep behavior""" minus_infinity = URXTIME # following staticmethods ideally would be # methods of an xtime object (in particular, # implementing the hooks needed for comparison # operators), but at this point we don't yet # have a dedicated xtime class @staticmethod def serialize_xtime(xt): return "%d.%d" % tuple(xt) @staticmethod def deserialize_xtime(xt): return tuple(int(x) for x in xt.split(".")) @staticmethod def native_xtime(xt): return xt @staticmethod def xtime_geq(xt0, xt1): return xt0 >= xt1 def make_xtime_opts(self, is_master, opts): if not 'create' in opts: opts['create'] = is_master if not 'default_xtime' in opts: opts['default_xtime'] = URXTIME def xtime_low(self, server, path, **opts): xt = server.xtime(path, self.uuid) if isinstance(xt, int) and xt != ENODATA: return xt if xt == ENODATA or xt < self.volmark: if opts['create']: xt = _xtime_now() server.aggregated.set_xtime(path, self.uuid, xt) else: xt = opts['default_xtime'] return xt def keepalive_payload_hook(self, timo, gap): # first grab a reference as self.volinfo # can be changed in main thread vi = self.volinfo if vi: # then have a private copy which we can mod vi = vi.copy() vi['timeout'] = int(time.time()) + timo else: # send keep-alives more frequently to # avoid a delay in announcing our volume info # to slave if it becomes established in the # meantime gap = min(10, gap) return (vi, gap) def volinfo_hook(self): return self.get_sys_volinfo() def xtime_reversion_hook(self, path, xtl, xtr): if xtr > xtl: raise GsyncdError("timestamp corruption for " + path) def need_sync(self, e, xte, xtrd): return xte > xtrd def set_slave_xtime(self, path, mark): self.slave.server.set_xtime(path, self.uuid, mark) self.slave.server.set_xtime_remote(path, self.uuid, mark) class PartialMixin(NormalMixin): """a variant tuned towards operation with a master that has partial info of the slave (brick typically)""" def xtime_reversion_hook(self, path, xtl, xtr): pass class RecoverMixin(NormalMixin): """a variant that differs from normal in terms of ignoring non-indexed files""" @staticmethod def make_xtime_opts(is_master, opts): if not 'create' in opts: opts['create'] = False if not 'default_xtime' in opts: opts['default_xtime'] = URXTIME def keepalive_payload_hook(self, timo, gap): return (None, gap) def volinfo_hook(self): return _volinfo_hook_relax_foreign(self) # Further mixins for certain tunable behaviors class SendmarkNormalMixin(object): def sendmark_regular(self, *a, **kw): return self.sendmark(*a, **kw) class SendmarkRsyncMixin(object): def sendmark_regular(self, *a, **kw): pass class PurgeNormalMixin(object): def purge_missing(self, path, names): self.slave.server.purge(path, names) class PurgeNoopMixin(object): def purge_missing(self, path, names): pass class GMasterCommon(object): """abstract class impementling master role""" KFGN = 0 KNAT = 1 def get_sys_volinfo(self): """query volume marks on fs root err out on multiple foreign masters """ fgn_vis, nat_vi = self.master.server.aggregated.foreign_volume_infos(), \ self.master.server.aggregated.native_volume_info() fgn_vi = None if fgn_vis: if len(fgn_vis) > 1: raise GsyncdError("cannot work with multiple foreign masters") fgn_vi = fgn_vis[0] return fgn_vi, nat_vi @property def uuid(self): if self.volinfo: return self.volinfo['uuid'] @property def volmark(self): if self.volinfo: return self.volinfo['volume_mark'] def xtime(self, path, *a, **opts): """get amended xtime as of amending, we can create missing xtime, or determine a valid value if what we get is expired (as of the volume mark expiry); way of amendig depends on @opts and on subject of query (master or slave). """ if a: rsc = a[0] else: rsc = self.master self.make_xtime_opts(rsc == self.master, opts) return self.xtime_low(rsc.server, path, **opts) def get_initial_crawl_data(self): # while persisting only 'files_syncd' is non-zero, rest of # the stats are nulls. lets keep it that way in case they # are needed to be used some day... default_data = {'files_syncd': 0, 'files_remaining': 0, 'bytes_remaining': 0, 'purges_remaining': 0} if getattr(gconf, 'state_detail_file', None): try: return json.load(open(gconf.state_detail_file)) except (IOError, OSError): ex = sys.exc_info()[1] if ex.errno == ENOENT: # Create file with initial data with open(gconf.state_detail_file, 'wb') as f: json.dump(default_data, f) return default_data else: raise return default_data def update_crawl_data(self): if getattr(gconf, 'state_detail_file', None): try: same_dir = os.path.dirname(gconf.state_detail_file) with NamedTemporaryFile(dir=same_dir, delete=False) as tmp: json.dump(self.total_crawl_stats, tmp) os.rename(tmp.name, gconf.state_detail_file) except (IOError, OSError): raise def __init__(self, master, slave): self.master = master self.slave = slave self.jobtab = {} self.syncer = Syncer(slave) # crawls vs. turns: # - self.crawls is simply the number of crawl() invocations on root # - one turn is a maximal consecutive sequence of crawls so that each # crawl in it detects a change to be synced # - self.turns is the number of turns since start # - self.total_turns is a limit so that if self.turns reaches it, then # we exit (for diagnostic purposes) # so, eg., if the master fs changes unceasingly, self.turns will remain 0. self.crawls = 0 self.turns = 0 self.total_turns = int(gconf.turns) self.crawl_start = datetime.now() self.lastreport = {'crawls': 0, 'turns': 0, 'time': 0} self.total_crawl_stats = None self.start = None self.change_seen = None # the actual volinfo we make use of self.volinfo = None self.terminate = False self.sleep_interval = 1 self.checkpoint_thread = None def init_keep_alive(cls): """start the keep-alive thread """ timo = int(gconf.timeout or 0) if timo > 0: def keep_alive(): while True: vi, gap = cls.keepalive_payload_hook(timo, timo * 0.5) cls.slave.server.keep_alive(vi) time.sleep(gap) t = Thread(target=keep_alive) t.start() def should_crawl(cls): return (gconf.glusterd_uuid in cls.master.server.node_uuid()) def register(self): self.register() def crawlwrap(self, oneshot=False): if oneshot: # it's important to do this during the oneshot crawl as # for a passive gsyncd (ie. in a replicate scenario) # the keepalive thread would keep the connection alive. self.init_keep_alive() # no need to maintain volinfo state machine. # in a cascading setup, each geo-replication session is # independent (ie. 'volume-mark' and 'xtime' are not # propogated). This is beacuse the slave's xtime is now # stored on the master itself. 'volume-mark' just identifies # that we are in a cascading setup and need to enable # 'geo-replication.ignore-pid-check' option. volinfo_sys = self.volinfo_hook() self.volinfo = volinfo_sys[self.KNAT] inter_master = volinfo_sys[self.KFGN] logging.info("%s master with volume id %s ..." % \ (inter_master and "intermediate" or "primary", self.uuid)) gconf.configinterface.set('volume_id', self.uuid) if self.volinfo: if self.volinfo['retval']: raise GsyncdError("master is corrupt") self.start_checkpoint_thread() else: raise GsyncdError("master volinfo unavailable") self.total_crawl_stats = self.get_initial_crawl_data() self.lastreport['time'] = time.time() logging.info('crawl interval: %d seconds' % self.sleep_interval) t0 = time.time() crawl = self.should_crawl() while not self.terminate: if self.start: logging.debug("... crawl #%d done, took %.6f seconds" % \ (self.crawls, time.time() - self.start)) self.start = time.time() should_display_info = self.start - self.lastreport['time'] >= 60 if should_display_info: logging.info("%d crawls, %d turns", self.crawls - self.lastreport['crawls'], self.turns - self.lastreport['turns']) self.lastreport.update(crawls = self.crawls, turns = self.turns, time = self.start) t1 = time.time() if int(t1 - t0) >= 60: #lets hardcode this check to 60 seconds crawl = self.should_crawl() t0 = t1 if not crawl: time.sleep(5) continue self.crawl() if oneshot: return time.sleep(self.sleep_interval) @classmethod def _checkpt_param(cls, chkpt, prm, xtimish=True): """use config backend to lookup a parameter belonging to checkpoint @chkpt""" cprm = getattr(gconf, 'checkpoint_' + prm, None) if not cprm: return chkpt_mapped, val = cprm.split(':', 1) if unescape(chkpt_mapped) != chkpt: return if xtimish: val = cls.deserialize_xtime(val) return val @classmethod def _set_checkpt_param(cls, chkpt, prm, val, xtimish=True): """use config backend to store a parameter associated with checkpoint @chkpt""" if xtimish: val = cls.serialize_xtime(val) gconf.configinterface.set('checkpoint_' + prm, "%s:%s" % (escape(chkpt), val)) @staticmethod def humantime(*tpair): """format xtime-like (sec, nsec) pair to human readable format""" ts = datetime.fromtimestamp(float('.'.join(str(n) for n in tpair))).\ strftime("%Y-%m-%d %H:%M:%S") if len(tpair) > 1: ts += '.' + str(tpair[1]) return ts def get_extra_info(self): str_info = '\nUptime=%s;FilesSyncd=%d;FilesPending=%d;BytesPending=%d;DeletesPending=%d;' % \ (self._crawl_time_format(datetime.now() - self.crawl_start), \ self.total_crawl_stats['files_syncd'], \ self.total_crawl_stats['files_remaining'], \ self.total_crawl_stats['bytes_remaining'], \ self.total_crawl_stats['purges_remaining']) str_info += '\0' logging.debug(str_info) return str_info def _crawl_time_format(self, crawl_time): # Ex: 5 years, 4 days, 20:23:10 years, days = divmod(crawl_time.days, 365.25) years = int(years) days = int(days) date="" m, s = divmod(crawl_time.seconds, 60) h, m = divmod(m, 60) if years != 0: date += "%s %s " % (years, "year" if years == 1 else "years") if days != 0: date += "%s %s " % (days, "day" if days == 1 else "days") date += "%s:%s:%s" % (string.zfill(h, 2), string.zfill(m, 2), string.zfill(s, 2)) return date def checkpt_service(self, chan, chkpt, tgt): """checkpoint service loop monitor and verify checkpoint status for @chkpt, and listen for incoming requests for whom we serve a pretty-formatted status report""" if not chkpt: # dummy loop for the case when there is no checkpt set while True: select([chan], [], []) conn, _ = chan.accept() conn.send(self.get_extra_info()) conn.close() completed = self._checkpt_param(chkpt, 'completed', xtimish=False) if completed: completed = tuple(int(x) for x in completed.split('.')) while True: s,_,_ = select([chan], [], [], (not completed) and 5 or None) # either request made and we re-check to not # give back stale data, or we still hunting for completion if self.native_xtime(tgt) and self.native_xtime(tgt) < self.volmark: # indexing has been reset since setting the checkpoint status = "is invalid" else: xtr = self.xtime('.', self.slave) if isinstance(xtr, int): raise GsyncdError("slave root directory is unaccessible (%s)", os.strerror(xtr)) ncompleted = self.xtime_geq(xtr, tgt) if completed and not ncompleted: # stale data logging.warn("completion time %s for checkpoint %s became stale" % \ (self.humantime(*completed), chkpt)) completed = None gconf.confdata.delete('checkpoint-completed') if ncompleted and not completed: # just reaching completion completed = "%.6f" % time.time() self._set_checkpt_param(chkpt, 'completed', completed, xtimish=False) completed = tuple(int(x) for x in completed.split('.')) logging.info("checkpoint %s completed" % chkpt) status = completed and \ "completed at " + self.humantime(completed[0]) or \ "not reached yet" if s: conn = None try: conn, _ = chan.accept() try: conn.send(" | checkpoint %s %s %s" % (chkpt, status, self.get_extra_info())) except: exc = sys.exc_info()[1] if (isinstance(exc, OSError) or isinstance(exc, IOError)) and \ exc.errno == EPIPE: logging.debug('checkpoint client disconnected') else: raise finally: if conn: conn.close() def start_checkpoint_thread(self): """prepare and start checkpoint service""" if self.checkpoint_thread or not ( getattr(gconf, 'state_socket_unencoded', None) and getattr(gconf, 'socketdir', None) ): return chan = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) state_socket = os.path.join(gconf.socketdir, md5hex(gconf.state_socket_unencoded) + ".socket") try: os.unlink(state_socket) except: if sys.exc_info()[0] == OSError: pass chan.bind(state_socket) chan.listen(1) checkpt_tgt = None if gconf.checkpoint: checkpt_tgt = self._checkpt_param(gconf.checkpoint, 'target') if not checkpt_tgt: checkpt_tgt = self.xtime('.') if isinstance(checkpt_tgt, int): raise GsyncdError("master root directory is unaccessible (%s)", os.strerror(checkpt_tgt)) self._set_checkpt_param(gconf.checkpoint, 'target', checkpt_tgt) logging.debug("checkpoint target %s has been determined for checkpoint %s" % \ (repr(checkpt_tgt), gconf.checkpoint)) t = Thread(target=self.checkpt_service, args=(chan, gconf.checkpoint, checkpt_tgt)) t.start() self.checkpoint_thread = t def add_job(self, path, label, job, *a, **kw): """insert @job function to job table at @path with @label""" if self.jobtab.get(path) == None: self.jobtab[path] = [] self.jobtab[path].append((label, a, lambda : job(*a, **kw))) def add_failjob(self, path, label): """invoke .add_job with a job that does nothing just fails""" logging.debug('salvaged: ' + label) self.add_job(path, label, lambda: False) def wait(self, path, *args): """perform jobs registered for @path Reset jobtab entry for @path, determine success as the conjuction of success of all the jobs. In case of success, call .sendmark on @path """ jobs = self.jobtab.pop(path, []) succeed = True for j in jobs: ret = j[-1]() if not ret: succeed = False if succeed and not args[0] == None: self.sendmark(path, *args) return succeed def sendmark(self, path, mark, adct=None): """update slave side xtime for @path to master side xtime also can send a setattr payload (see Server.setattr). """ if adct: self.slave.server.setattr(path, adct) self.set_slave_xtime(path, mark) class GMasterChangelogMixin(GMasterCommon): """ changelog based change detection and syncing """ # index for change type and entry IDX_START = 0 IDX_END = 2 POS_GFID = 0 POS_TYPE = 1 POS_ENTRY1 = 2 POS_ENTRY2 = 3 # renames _CL_TYPE_DATA_PFX = "D " _CL_TYPE_METADATA_PFX = "M " _CL_TYPE_ENTRY_PFX = "E " TYPE_GFID = [_CL_TYPE_DATA_PFX] # ignoring metadata ops TYPE_ENTRY = [_CL_TYPE_ENTRY_PFX] # flat directory heirarchy for gfid based access FLAT_DIR_HIERARCHY = '.' # maximum retries per changelog before giving up MAX_RETRIES = 10 def fallback_xsync(self): logging.info('falling back to xsync mode') gconf.configinterface.set('change-detector', 'xsync') selfkill() def setup_working_dir(self): workdir = os.path.join(gconf.working_dir, md5hex(gconf.local_path)) logfile = os.path.join(workdir, 'changes.log') logging.debug('changelog working dir %s (log: %s)' % (workdir, logfile)) return (workdir, logfile) # update stats from *this* crawl def update_cumulative_stats(self, files_pending): self.total_crawl_stats['files_remaining'] = files_pending['count'] self.total_crawl_stats['bytes_remaining'] = files_pending['bytes'] self.total_crawl_stats['purges_remaining'] = files_pending['purge'] # sync data def syncdata(self, datas): logging.debug('datas: %s' % (datas)) for data in datas: logging.debug('candidate for syncing %s' % data) pb = self.syncer.add(data) def regjob(se, xte, pb): rv = pb.wait() if rv[0]: logging.debug('synced ' + se) return True else: if rv[1] in [23, 24]: # stat to check if the file exist st = lstat(se) if isinstance(st, int): # file got unlinked in the interim return True logging.warn('Rsync: %s [errcode: %d]' % (se, rv[1])) self.add_job(self.FLAT_DIR_HIERARCHY, 'reg', regjob, data, None, pb) if self.wait(self.FLAT_DIR_HIERARCHY, None): return True def process_change(self, change, done, retry): pfx = gauxpfx() clist = [] entries = [] datas = set() # basic crawl stats: files and bytes files_pending = {'count': 0, 'purge': 0, 'bytes': 0, 'files': []} try: f = open(change, "r") clist = f.readlines() f.close() except IOError: raise def edct(op, **ed): dct = {} dct['op'] = op for k in ed: if k == 'stat': st = ed[k] dst = dct['stat'] = {} dst['uid'] = st.st_uid dst['gid'] = st.st_gid dst['mode'] = st.st_mode else: dct[k] = ed[k] return dct # regular file update: bytes & count def _update_reg(entry, size): if not entry in files_pending['files']: files_pending['count'] += 1 files_pending['bytes'] += size files_pending['files'].append(entry) # updates for directories, symlinks etc.. def _update_rest(): files_pending['count'] += 1 # entry count def entry_update(entry, size, mode): if stat.S_ISREG(mode): _update_reg(entry, size) else: _update_rest() # purge count def purge_update(): files_pending['purge'] += 1 for e in clist: e = e.strip() et = e[self.IDX_START:self.IDX_END] ec = e[self.IDX_END:].split(' ') if et in self.TYPE_ENTRY: ty = ec[self.POS_TYPE] en = unescape(os.path.join(pfx, ec[self.POS_ENTRY1])) gfid = ec[self.POS_GFID] # definitely need a better way bucketize entry ops if ty in ['UNLINK', 'RMDIR']: purge_update() entries.append(edct(ty, gfid=gfid, entry=en)) continue go = os.path.join(pfx, gfid) st = lstat(go) if isinstance(st, int): if ty == 'RENAME': entries.append(edct('UNLINK', gfid=gfid, entry=en)) else: logging.debug('file %s got purged in the interim' % go) continue entry_update(go, st.st_size, st.st_mode) if ty in ['CREATE', 'MKDIR', 'MKNOD']: entries.append(edct(ty, stat=st, entry=en, gfid=gfid)) elif ty == 'LINK': entries.append(edct(ty, stat=st, entry=en, gfid=gfid)) elif ty == 'SYMLINK': rl = errno_wrap(os.readlink, [en], [ENOENT]) if isinstance(rl, int): continue entries.append(edct(ty, stat=st, entry=en, gfid=gfid, link=rl)) elif ty == 'RENAME': e2 = unescape(os.path.join(pfx, ec[self.POS_ENTRY2])) entries.append(edct(ty, gfid=gfid, entry=en, entry1=e2, stat=st)) else: logging.warn('ignoring %s [op %s]' % (gfid, ty)) elif et in self.TYPE_GFID: go = os.path.join(pfx, ec[0]) st = lstat(go) if isinstance(st, int): logging.debug('file %s got purged in the interim' % go) continue entry_update(go, st.st_size, st.st_mode) datas.update([go]) logging.debug('entries: %s' % repr(entries)) if not retry: self.update_cumulative_stats(files_pending) # sync namespace if (entries): self.slave.server.entry_ops(entries) # sync data if self.syncdata(datas): if done: self.master.server.changelog_done(change) return True def sync_done(self): self.total_crawl_stats['files_syncd'] += self.total_crawl_stats['files_remaining'] self.total_crawl_stats['files_remaining'] = 0 self.total_crawl_stats['bytes_remaining'] = 0 self.total_crawl_stats['purges_remaining'] = 0 self.update_crawl_data() def process(self, changes, done=1): for change in changes: tries = 0 retry = False while True: logging.debug('processing change %s' % change) if self.process_change(change, done, retry): self.sync_done() break retry = True tries += 1 if tries == self.MAX_RETRIES: logging.warn('changelog %s could not be processed - moving on...' % os.path.basename(change)) self.sync_done() if done: self.master.server.changelog_done(change) break # it's either entry_ops() or Rsync that failed to do it's # job. Mostly it's entry_ops() [which currently has a problem # of failing to create an entry but failing to return an errno] # Therefore we do not know if it's either Rsync or the freaking # entry_ops() that failed... so we retry the _whole_ changelog # again. # TODO: remove entry retries when it's gets fixed. logging.warn('incomplete sync, retrying changelog: %s' % change) time.sleep(0.5) self.turns += 1 def upd_stime(self, stime): if not stime == URXTIME: self.sendmark(self.FLAT_DIR_HIERARCHY, stime) def crawl(self): changes = [] try: self.master.server.changelog_scan() self.crawls += 1 except OSError: self.fallback_xsync() changes = self.master.server.changelog_getchanges() if changes: xtl = self.xtime(self.FLAT_DIR_HIERARCHY) if isinstance(xtl, int): raise GsyncdError('master is corrupt') logging.debug('processing changes %s' % repr(changes)) self.process(changes) self.upd_stime(xtl) def register(self): (workdir, logfile) = self.setup_working_dir() self.sleep_interval = int(gconf.change_interval) # register with the changelog library try: # 9 == log level (DEBUG) # 5 == connection retries self.master.server.changelog_register(gconf.local_path, workdir, logfile, 9, 5) except OSError: self.fallback_xsync() # control should not reach here raise class GMasterXsyncMixin(GMasterChangelogMixin): """ This crawl needs to be xtime based (as of now it's not. this is beacuse we generate CHANGELOG file during each crawl which is then processed by process_change()). For now it's used as a one-shot initial sync mechanism and only syncs directories, regular files and symlinks. """ def register(self): self.sleep_interval = 60 self.tempdir = self.setup_working_dir()[0] self.tempdir = os.path.join(self.tempdir, 'xsync') logging.info('xsync temp directory: %s' % self.tempdir) try: os.makedirs(self.tempdir) except OSError: ex = sys.exc_info()[1] if ex.errno == EEXIST and os.path.isdir(self.tempdir): pass else: raise def write_entry_change(self, prefix, data=[]): self.fh.write("%s %s\n" % (prefix, ' '.join(data))) def open(self): try: self.xsync_change = os.path.join(self.tempdir, 'XSYNC-CHANGELOG.' + str(int(time.time()))) self.fh = open(self.xsync_change, 'w') except IOError: raise def close(self): self.fh.close() def fname(self): return self.xsync_change def crawl(self, path='.', xtr=None, done=0): """ generate a CHANGELOG file consumable by process_change """ if path == '.': self.open() self.crawls += 1 if not xtr: # get the root stime and use it for all comparisons xtr = self.xtime('.', self.slave) if isinstance(xtr, int): if xtr != ENOENT: raise GsyncdError('slave is corrupt') xtr = self.minus_infinity xtl = self.xtime(path) if isinstance(xtl, int): raise GsyncdError('master is corrupt') if xtr == xtl: if path == '.': self.close() return self.xtime_reversion_hook(path, xtl, xtr) logging.debug("entering " + path) dem = self.master.server.entries(path) pargfid = self.master.server.gfid(path) if isinstance(pargfid, int): logging.warn('skipping directory %s' % (path)) for e in dem: bname = e e = os.path.join(path, e) st = lstat(e) if isinstance(st, int): logging.warn('%s got purged in the interim..' % e) continue gfid = self.master.server.gfid(e) if isinstance(gfid, int): logging.warn('skipping entry %s..' % (e)) continue xte = self.xtime(e) if isinstance(xte, int): raise GsyncdError('master is corrupt') if not self.need_sync(e, xte, xtr): continue mo = st.st_mode if stat.S_ISDIR(mo): self.write_entry_change("E", [gfid, 'MKDIR', escape(os.path.join(pargfid, bname))]) self.crawl(e, xtr) elif stat.S_ISREG(mo): self.write_entry_change("E", [gfid, 'CREATE', escape(os.path.join(pargfid, bname))]) self.write_entry_change("D", [gfid]) elif stat.S_ISLNK(mo): self.write_entry_change("E", [gfid, 'SYMLINK', escape(os.path.join(pargfid, bname))]) else: logging.info('ignoring %s' % e) if path == '.': logging.info('processing xsync changelog %s' % self.fname()) self.close() self.process([self.fname()], done) self.upd_stime(xtl) class BoxClosedErr(Exception): pass class PostBox(list): """synchronized collection for storing things thought of as "requests" """ def __init__(self, *a): list.__init__(self, *a) # too bad Python stdlib does not have read/write locks... # it would suffivce to grab the lock in .append as reader, in .close as writer self.lever = Condition() self.open = True self.done = False def wait(self): """wait on requests to be processed""" self.lever.acquire() if not self.done: self.lever.wait() self.lever.release() return self.result def wakeup(self, data): """wake up requestors with the result""" self.result = data self.lever.acquire() self.done = True self.lever.notifyAll() self.lever.release() def append(self, e): """post a request""" self.lever.acquire() if not self.open: raise BoxClosedErr list.append(self, e) self.lever.release() def close(self): """prohibit the posting of further requests""" self.lever.acquire() self.open = False self.lever.release() class Syncer(object): """a staged queue to relay rsync requests to rsync workers By "staged queue" its meant that when a consumer comes to the queue, it takes _all_ entries, leaving the queue empty. (I don't know if there is an official term for this pattern.) The queue uses a PostBox to accumulate incoming items. When a consumer (rsync worker) comes, a new PostBox is set up and the old one is passed on to the consumer. Instead of the simplistic scheme of having one big lock which synchronizes both the addition of new items and PostBox exchanges, use a separate lock to arbitrate consumers, and rely on PostBox's synchronization mechanisms take care about additions. There is a corner case racy situation, producers vs. consumers, which is not handled by this scheme: namely, when the PostBox exchange occurs in between being passed to the producer for posting and the post placement. But that's what Postbox.close is for: such a posting will find the PostBox closed, in which case the producer can re-try posting against the actual PostBox of the queue. To aid accumlation of items in the PostBoxen before grabbed by an rsync worker, the worker goes to sleep a bit after each completed syncjob. """ def __init__(self, slave): """spawn worker threads""" self.slave = slave self.lock = Lock() self.pb = PostBox() self.bytes_synced = 0 for i in range(int(gconf.sync_jobs)): t = Thread(target=self.syncjob) t.start() def syncjob(self): """the life of a worker""" while True: pb = None while True: self.lock.acquire() if self.pb: pb, self.pb = self.pb, PostBox() self.lock.release() if pb: break time.sleep(0.5) pb.close() po = self.slave.rsync(pb) if po.returncode == 0: ret = (True, 0) elif po.returncode in (23, 24): # partial transfer (cf. rsync(1)), that's normal ret = (False, po.returncode) else: po.errfail() pb.wakeup(ret) def add(self, e): while True: pb = self.pb try: pb.append(e) return pb except BoxClosedErr: pass