src/allmydata/mutable/checker.py

   1
   2 from allmydata.uri import from_string
   3 from allmydata.util import base32, idlib, log
   4 from allmydata.check_results import CheckAndRepairResults, CheckResults
   5
   6 from allmydata.mutable.common import MODE_CHECK, CorruptShareError
   7 from allmydata.mutable.servermap import ServerMap, ServermapUpdater
   8 from allmydata.mutable.retrieve import Retrieve # for verifying
   9
  10 class MutableChecker:
  11
  12     def __init__(self, node, storage_broker, history, monitor):
  13         self._node = node
  14         self._storage_broker = storage_broker
  15         self._history = history
  16         self._monitor = monitor
  17         self.bad_shares = [] # list of (nodeid,shnum,failure)
  18         self._storage_index = self._node.get_storage_index()
  19         self.results = CheckResults(from_string(node.get_uri()), self._storage_index)
  20         self.need_repair = False
  21         self.responded = set() # set of (binary) nodeids
  22
  23     def check(self, verify=False, add_lease=False):
  24         servermap = ServerMap()
  25         # Updating the servermap in MODE_CHECK will stand a good chance
  26         # of finding all of the shares, and getting a good idea of
  27         # recoverability, etc, without verifying.
  28         u = ServermapUpdater(self._node, self._storage_broker, self._monitor,
  29                              servermap, MODE_CHECK, add_lease=add_lease)
  30         if self._history:
  31             self._history.notify_mapupdate(u.get_status())
  32         d = u.update()
  33         d.addCallback(self._got_mapupdate_results)
  34         if verify:
  35             d.addCallback(self._verify_all_shares)
  36         d.addCallback(lambda res: servermap)
  37         d.addCallback(self._fill_checker_results, self.results)
  38         d.addCallback(lambda res: self.results)
  39         return d
  40
  41     def _got_mapupdate_results(self, servermap):
  42         # the file is healthy if there is exactly one recoverable version, it
  43         # has at least N distinct shares, and there are no unrecoverable
  44         # versions: all existing shares will be for the same version.
  45         self._monitor.raise_if_cancelled()
  46         self.best_version = None
  47         num_recoverable = len(servermap.recoverable_versions())
  48         if num_recoverable:
  49             self.best_version = servermap.best_recoverable_version()
  50
  51         # The file is unhealthy and needs to be repaired if:
  52         # - There are unrecoverable versions.
  53         if servermap.unrecoverable_versions():
  54             self.need_repair = True
  55         # - There isn't a recoverable version.
  56         if num_recoverable != 1:
  57             self.need_repair = True
  58         # - The best recoverable version is missing some shares.
  59         if self.best_version:
  60             available_shares = servermap.shares_available()
  61             (num_distinct_shares, k, N) = available_shares[self.best_version]
  62             if num_distinct_shares < N:
  63                 self.need_repair = True
  64
  65         return servermap
  66
  67     def _verify_all_shares(self, servermap):
  68         # read every byte of each share
  69         #
  70         # This logic is going to be very nearly the same as the
  71         # downloader. I bet we could pass the downloader a flag that
  72         # makes it do this, and piggyback onto that instead of
  73         # duplicating a bunch of code.
  74         #
  75         # Like:
  76         #  r = Retrieve(blah, blah, blah, verify=True)
  77         #  d = r.download()
  78         #  (wait, wait, wait, d.callback)
  79         #
  80         #  Then, when it has finished, we can check the servermap (which
  81         #  we provided to Retrieve) to figure out which shares are bad,
  82         #  since the Retrieve process will have updated the servermap as
  83         #  it went along.
  84         #
  85         #  By passing the verify=True flag to the constructor, we are
  86         #  telling the downloader a few things.
  87         #
  88         #  1. It needs to download all N shares, not just K shares.
  89         #  2. It doesn't need to decrypt or decode the shares, only
  90         #     verify them.
  91         if not self.best_version:
  92             return
  93
  94         r = Retrieve(self._node, servermap, self.best_version, verify=True)
  95         d = r.download()
  96         d.addCallback(self._process_bad_shares)
  97         return d
  98
  99
 100     def _process_bad_shares(self, bad_shares):
 101         if bad_shares:
 102             self.need_repair = True
 103         self.bad_shares = bad_shares
 104
 105
 106     def _count_shares(self, smap, version):
 107         available_shares = smap.shares_available()
 108         (num_distinct_shares, k, N) = available_shares[version]
 109         counters = {}
 110         counters["count-shares-good"] = num_distinct_shares
 111         counters["count-shares-needed"] = k
 112         counters["count-shares-expected"] = N
 113         good_hosts = smap.all_peers_for_version(version)
 114         counters["count-good-share-hosts"] = len(good_hosts)
 115         vmap = smap.make_versionmap()
 116         counters["count-wrong-shares"] = sum([len(shares)
 117                                           for verinfo,shares in vmap.items()
 118                                           if verinfo != version])
 119
 120         return counters
 121
 122     def _fill_checker_results(self, smap, r):
 123         self._monitor.raise_if_cancelled()
 124         r.set_servermap(smap.copy())
 125         healthy = True
 126         data = {}
 127         report = []
 128         summary = []
 129         vmap = smap.make_versionmap()
 130         recoverable = smap.recoverable_versions()
 131         unrecoverable = smap.unrecoverable_versions()
 132         data["count-recoverable-versions"] = len(recoverable)
 133         data["count-unrecoverable-versions"] = len(unrecoverable)
 134
 135         if recoverable:
 136             report.append("Recoverable Versions: " +
 137                           "/".join(["%d*%s" % (len(vmap[v]),
 138                                                smap.summarize_version(v))
 139                                     for v in recoverable]))
 140         if unrecoverable:
 141             report.append("Unrecoverable Versions: " +
 142                           "/".join(["%d*%s" % (len(vmap[v]),
 143                                                smap.summarize_version(v))
 144                                     for v in unrecoverable]))
 145         if smap.unrecoverable_versions():
 146             healthy = False
 147             summary.append("some versions are unrecoverable")
 148             report.append("Unhealthy: some versions are unrecoverable")
 149         if len(recoverable) == 0:
 150             healthy = False
 151             summary.append("no versions are recoverable")
 152             report.append("Unhealthy: no versions are recoverable")
 153         if len(recoverable) > 1:
 154             healthy = False
 155             summary.append("multiple versions are recoverable")
 156             report.append("Unhealthy: there are multiple recoverable versions")
 157
 158         needs_rebalancing = False
 159         if recoverable:
 160             best_version = smap.best_recoverable_version()
 161             report.append("Best Recoverable Version: " +
 162                           smap.summarize_version(best_version))
 163             counters = self._count_shares(smap, best_version)
 164             data.update(counters)
 165             s = counters["count-shares-good"]
 166             k = counters["count-shares-needed"]
 167             N = counters["count-shares-expected"]
 168             if s < N:
 169                 healthy = False
 170                 report.append("Unhealthy: best version has only %d shares "
 171                               "(encoding is %d-of-%d)" % (s, k, N))
 172                 summary.append("%d shares (enc %d-of-%d)" % (s, k, N))
 173             hosts = smap.all_peers_for_version(best_version)
 174             needs_rebalancing = bool( len(hosts) < N )
 175         elif unrecoverable:
 176             healthy = False
 177             # find a k and N from somewhere
 178             first = list(unrecoverable)[0]
 179             # not exactly the best version, but that doesn't matter too much
 180             data.update(self._count_shares(smap, first))
 181             # leave needs_rebalancing=False: the file being unrecoverable is
 182             # the bigger problem
 183         else:
 184             # couldn't find anything at all
 185             data["count-shares-good"] = 0
 186             data["count-shares-needed"] = 3 # arbitrary defaults
 187             data["count-shares-expected"] = 10
 188             data["count-good-share-hosts"] = 0
 189             data["count-wrong-shares"] = 0
 190
 191         if self.bad_shares:
 192             data["count-corrupt-shares"] = len(self.bad_shares)
 193             data["list-corrupt-shares"] = locators = []
 194             report.append("Corrupt Shares:")
 195             summary.append("Corrupt Shares:")
 196             for (peerid, shnum, f) in sorted(self.bad_shares):
 197                 locators.append( (peerid, self._storage_index, shnum) )
 198                 s = "%s-sh%d" % (idlib.shortnodeid_b2a(peerid), shnum)
 199                 if f.check(CorruptShareError):
 200                     ft = f.value.reason
 201                 else:
 202                     ft = str(f)
 203                 report.append(" %s: %s" % (s, ft))
 204                 summary.append(s)
 205                 p = (peerid, self._storage_index, shnum, f)
 206                 r.problems.append(p)
 207                 msg = ("CorruptShareError during mutable verify, "
 208                        "peerid=%(peerid)s, si=%(si)s, shnum=%(shnum)d, "
 209                        "where=%(where)s")
 210                 log.msg(format=msg, peerid=idlib.nodeid_b2a(peerid),
 211                         si=base32.b2a(self._storage_index),
 212                         shnum=shnum,
 213                         where=ft,
 214                         level=log.WEIRD, umid="EkK8QA")
 215         else:
 216             data["count-corrupt-shares"] = 0
 217             data["list-corrupt-shares"] = []
 218
 219         sharemap = {}
 220         for verinfo in vmap:
 221             for (shnum, peerid, timestamp) in vmap[verinfo]:
 222                 shareid = "%s-sh%d" % (smap.summarize_version(verinfo), shnum)
 223                 if shareid not in sharemap:
 224                     sharemap[shareid] = []
 225                 sharemap[shareid].append(peerid)
 226         data["sharemap"] = sharemap
 227         data["servers-responding"] = list(smap.reachable_peers)
 228
 229         r.set_healthy(healthy)
 230         r.set_recoverable(bool(recoverable))
 231         r.set_needs_rebalancing(needs_rebalancing)
 232         r.set_data(data)
 233         if healthy:
 234             r.set_summary("Healthy")
 235         else:
 236             r.set_summary("Unhealthy: " + " ".join(summary))
 237         r.set_report(report)
 238
 239
 240 class MutableCheckAndRepairer(MutableChecker):
 241     def __init__(self, node, storage_broker, history, monitor):
 242         MutableChecker.__init__(self, node, storage_broker, history, monitor)
 243         self.cr_results = CheckAndRepairResults(self._storage_index)
 244         self.cr_results.pre_repair_results = self.results
 245         self.need_repair = False
 246
 247     def check(self, verify=False, add_lease=False):
 248         d = MutableChecker.check(self, verify, add_lease)
 249         d.addCallback(self._maybe_repair)
 250         d.addCallback(lambda res: self.cr_results)
 251         return d
 252
 253     def _maybe_repair(self, res):
 254         self._monitor.raise_if_cancelled()
 255         if not self.need_repair:
 256             self.cr_results.post_repair_results = self.results
 257             return
 258         if self._node.is_readonly():
 259             # ticket #625: we cannot yet repair read-only mutable files
 260             self.cr_results.post_repair_results = self.results
 261             self.cr_results.repair_attempted = False
 262             return
 263         self.cr_results.repair_attempted = True
 264         d = self._node.repair(self.results)
 265         def _repair_finished(repair_results):
 266             self.cr_results.repair_successful = repair_results.get_successful()
 267             r = CheckResults(from_string(self._node.get_uri()), self._storage_index)
 268             self.cr_results.post_repair_results = r
 269             self._fill_checker_results(repair_results.servermap, r)
 270             self.cr_results.repair_results = repair_results # TODO?
 271         def _repair_error(f):
 272             # I'm not sure if I want to pass through a failure or not.
 273             self.cr_results.repair_successful = False
 274             self.cr_results.repair_failure = f # TODO?
 275             #self.cr_results.post_repair_results = ??
 276             return f
 277         d.addCallbacks(_repair_finished, _repair_error)
 278         return d