3 I contain the client-side code which speaks to storage servers, in particular
4 the foolscap-based server implemented in src/allmydata/storage/*.py .
9 # 1: implement StorageFarmBroker (i.e. "storage broker"), change Client to
10 # create it, change uploader/servermap to get rrefs from it. ServerFarm calls
11 # IntroducerClient.subscribe_to . ServerFarm hides descriptors, passes rrefs
12 # to clients. webapi status pages call broker.get_info_about_serverid.
14 # 2: move get_info methods to the descriptor, webapi status pages call
15 # broker.get_descriptor_for_serverid().get_info
17 # 3?later?: store descriptors in UploadResults/etc instead of serverids,
18 # webapi status pages call descriptor.get_info and don't use storage_broker
21 # 4: enable static config: tahoe.cfg can add descriptors. Make the introducer
22 # optional. This closes #467
24 # 5: implement NativeStorageClient, pass it to Tahoe2PeerSelector and other
25 # clients. Clients stop doing callRemote(), use NativeStorageClient methods
26 # instead (which might do something else, i.e. http or whatever). The
27 # introducer and tahoe.cfg only create NativeStorageClients for now.
29 # 6: implement other sorts of IStorageClient classes: S3, etc
33 from zope.interface import implements
34 from foolscap.api import eventually
35 from allmydata.interfaces import IStorageBroker, IDisplayableServer, IServer
36 from allmydata.util import log, base32
37 from allmydata.util.assertutil import precondition
38 from allmydata.util.rrefutil import add_version_to_remote_reference
39 from allmydata.util.hashutil import sha1
41 # who is responsible for de-duplication?
43 # IC remembers the unpacked announcements it receives, to provide for late
44 # subscribers and to remove duplicates
46 # if a client subscribes after startup, will they receive old announcements?
49 # who will be responsible for signature checking?
50 # make it be IntroducerClient, so they can push the filter outwards and
51 # reduce inbound network traffic
53 # what should the interface between StorageFarmBroker and IntroducerClient
55 # don't pass signatures: only pass validated blessed-objects
57 class StorageFarmBroker:
58 implements(IStorageBroker)
59 """I live on the client, and know about storage servers. For each server
60 that is participating in a grid, I either maintain a connection to it or
61 remember enough information to establish a connection to it on demand.
62 I'm also responsible for subscribing to the IntroducerClient to find out
63 about new servers as they are announced by the Introducer.
65 def __init__(self, tub, permute_peers):
67 assert permute_peers # False not implemented yet
68 self.permute_peers = permute_peers
69 # self.servers maps serverid -> IServer, and keeps track of all the
70 # storage servers that we've heard about. Each descriptor manages its
71 # own Reconnector, and will give us a RemoteReference when we ask
74 self.introducer_client = None
76 # these two are used in unit tests
77 def test_add_rref(self, serverid, rref, ann):
78 s = NativeStorageServer(serverid, ann.copy())
80 s._is_connected = True
81 self.servers[serverid] = s
83 def test_add_server(self, serverid, s):
84 self.servers[serverid] = s
86 def use_introducer(self, introducer_client):
87 self.introducer_client = ic = introducer_client
88 ic.subscribe_to("storage", self._got_announcement)
90 def _got_announcement(self, key_s, ann):
92 precondition(isinstance(key_s, str), key_s)
93 precondition(key_s.startswith("v0-"), key_s)
94 assert ann["service-name"] == "storage"
95 s = NativeStorageServer(key_s, ann)
96 serverid = s.get_serverid()
97 old = self.servers.get(serverid)
99 if old.get_announcement() == ann:
102 del self.servers[serverid]
103 old.stop_connecting()
104 # now we forget about them and start using the new one
105 self.servers[serverid] = s
106 s.start_connecting(self.tub, self._trigger_connections)
107 # the descriptor will manage their own Reconnector, and each time we
108 # need servers, we'll ask them if they're connected or not.
110 def _trigger_connections(self):
111 # when one connection is established, reset the timers on all others,
112 # to trigger a reconnection attempt in one second. This is intended
113 # to accelerate server connections when we've been offline for a
114 # while. The goal is to avoid hanging out for a long time with
115 # connections to only a subset of the servers, which would increase
116 # the chances that we'll put shares in weird places (and not update
117 # existing shares of mutable files). See #374 for more details.
118 for dsc in self.servers.values():
121 def get_servers_for_psi(self, peer_selection_index):
122 # return a list of server objects (IServers)
123 assert self.permute_peers == True
124 def _permuted(server):
125 seed = server.get_permutation_seed()
126 return sha1(peer_selection_index + seed).digest()
127 return sorted(self.get_connected_servers(), key=_permuted)
129 def get_all_serverids(self):
130 return frozenset(self.servers.keys())
132 def get_connected_servers(self):
133 return frozenset([s for s in self.servers.values() if s.is_connected()])
135 def get_known_servers(self):
136 return frozenset(self.servers.values())
138 def get_nickname_for_serverid(self, serverid):
139 if serverid in self.servers:
140 return self.servers[serverid].get_nickname()
143 def get_stub_server(self, serverid):
144 if serverid in self.servers:
145 return self.servers[serverid]
146 return StubServer(serverid)
149 implements(IDisplayableServer)
150 def __init__(self, serverid):
151 self.serverid = serverid # binary tubid
152 def get_serverid(self):
155 return base32.b2a(self.serverid)[:8]
156 def get_longname(self):
157 return base32.b2a(self.serverid)
158 def get_nickname(self):
161 class NativeStorageServer:
162 """I hold information about a storage server that we want to connect to.
163 If we are connected, I hold the RemoteReference, their host address, and
164 the their version information. I remember information about when we were
165 last connected too, even if we aren't currently connected.
167 @ivar announcement_time: when we first heard about this service
168 @ivar last_connect_time: when we last established a connection
169 @ivar last_loss_time: when we last lost a connection
171 @ivar version: the server's versiondict, from the most recent announcement
172 @ivar nickname: the server's self-reported nickname (unicode), same
174 @ivar rref: the RemoteReference, if connected, otherwise None
175 @ivar remote_host: the IAddress, if connected, otherwise None
180 "http://allmydata.org/tahoe/protocols/storage/v1" :
181 { "maximum-immutable-share-size": 2**32,
182 "tolerates-immutable-read-overrun": False,
183 "delete-mutable-shares-with-zero-length-writev": False,
185 "application-version": "unknown: no get_version()",
188 def __init__(self, key_s, ann, min_shares=1):
190 self.announcement = ann
191 self.min_shares = min_shares
193 assert "anonymous-storage-FURL" in ann, ann
194 furl = str(ann["anonymous-storage-FURL"])
195 m = re.match(r'pb://(\w+)@', furl)
197 tubid_s = m.group(1).lower()
198 self._tubid = base32.a2b(tubid_s)
199 assert "permutation-seed-base32" in ann, ann
200 ps = base32.a2b(str(ann["permutation-seed-base32"]))
201 self._permutation_seed = ps
204 self._long_description = key_s
205 if key_s.startswith("v0-"):
206 # remove v0- prefix from abbreviated name
207 self._short_description = key_s[3:3+8]
209 self._short_description = key_s[:8]
211 self._long_description = tubid_s
212 self._short_description = tubid_s[:6]
214 self.announcement_time = time.time()
215 self.last_connect_time = None
216 self.last_loss_time = None
217 self.remote_host = None
219 self._is_connected = False
220 self._reconnector = None
221 self._trigger_cb = None
223 # Special methods used by copy.copy() and copy.deepcopy(). When those are
224 # used in allmydata.immutable.filenode to copy CheckResults during
225 # repair, we want it to treat the IServer instances as singletons, and
226 # not attempt to duplicate them..
229 def __deepcopy__(self, memodict):
233 return "<NativeStorageServer for %s>" % self.get_name()
234 def get_serverid(self):
235 return self._tubid # XXX replace with self.key_s
236 def get_permutation_seed(self):
237 return self._permutation_seed
238 def get_version(self):
240 return self.rref.version
242 def get_name(self): # keep methodname short
243 # TODO: decide who adds [] in the short description. It should
244 # probably be the output side, not here.
245 return self._short_description
246 def get_longname(self):
247 return self._long_description
248 def get_lease_seed(self):
250 def get_foolscap_write_enabler_seed(self):
253 def get_nickname(self):
254 return self.announcement["nickname"].decode("utf-8")
255 def get_announcement(self):
256 return self.announcement
257 def get_remote_host(self):
258 return self.remote_host
259 def is_connected(self):
260 return self._is_connected
261 def get_last_connect_time(self):
262 return self.last_connect_time
263 def get_last_loss_time(self):
264 return self.last_loss_time
265 def get_announcement_time(self):
266 return self.announcement_time
268 def start_connecting(self, tub, trigger_cb):
269 furl = str(self.announcement["anonymous-storage-FURL"])
270 self._trigger_cb = trigger_cb
271 self._reconnector = tub.connectTo(furl, self._got_connection)
273 def _got_connection(self, rref):
274 lp = log.msg(format="got connection to %(name)s, getting versions",
275 name=self.get_name(),
276 facility="tahoe.storage_broker", umid="coUECQ")
278 eventually(self._trigger_cb)
279 default = self.VERSION_DEFAULTS
280 d = add_version_to_remote_reference(rref, default)
281 d.addCallback(self._got_versioned_service, lp)
282 d.addErrback(log.err, format="storageclient._got_connection",
283 name=self.get_name(), umid="Sdq3pg")
285 def _got_versioned_service(self, rref, lp):
286 log.msg(format="%(name)s provided version info %(version)s",
287 name=self.get_name(), version=rref.version,
288 facility="tahoe.storage_broker", umid="SWmJYg",
289 level=log.NOISY, parent=lp)
291 self.last_connect_time = time.time()
292 self.remote_host = rref.getPeer()
294 self._is_connected = True
295 rref.notifyOnDisconnect(self._lost)
301 log.msg(format="lost connection to %(name)s", name=self.get_name(),
302 facility="tahoe.storage_broker", umid="zbRllw")
303 self.last_loss_time = time.time()
304 # self.rref is now stale: all callRemote()s will get a
305 # DeadReferenceError. We leave the stale reference in place so that
306 # uploader/downloader code (which received this IServer through
307 # get_connected_servers() or get_servers_for_psi()) can continue to
308 # use s.get_rref().callRemote() and not worry about it being None.
309 self._is_connected = False
310 self.remote_host = None
312 def stop_connecting(self):
313 # used when this descriptor has been superceded by another
314 self._reconnector.stopConnecting()
316 def try_to_connect(self):
317 # used when the broker wants us to hurry up
318 self._reconnector.reset()
320 class UnknownServerTypeError(Exception):