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Fix confusion between IStorageServer and the thing above it

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IStorageServer is what uses a connection.  You need a thing above it to _get_
a connection.
This commit is contained in:
Jean-Paul Calderone 2019-07-02 14:57:20 -04:00
parent 59546944ce
commit 2616c66a49
2 changed files with 156 additions and 24 deletions
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134
src/allmydata/storage_client.py
View File

@ -34,7 +34,11 @@ from ConfigParser import (
NoSectionError,
)
import attr
from zope.interface import implementer
from zope.interface import (
Attribute,
Interface,
implementer,
)
from twisted.internet import defer
from twisted.application import service
from twisted.plugin import (
@ -369,19 +373,70 @@ class StubServer(object):
return "?"
@attr.s(frozen=True)
class _AnonymousStorage(object):
class IFoolscapStorageServer(Interface):
"""
Abstraction for connecting to an anonymous storage server.
An internal interface that mediates between ``NativeStorageServer`` and
Foolscap-based ``IStorageServer`` implementations.
"""
nickname = Attribute("""
A name for this server for presentation to users.
""")
permutation_seed = Attribute("""
A stable value associated with this server which a client can use as an
input to the server selection permutation ordering.
""")
tubid = Attribute("""
The identifier for the Tub in which the server is run.
""")
storage_server = Attribute("""
An IStorageServer provide which implements a concrete Foolscap-based
protocol for communicating with the server.
""")
name = Attribute("""
Another name for this server for presentation to users.
""")
longname = Attribute("""
*Another* name for this server for presentation to users.
""")
lease_seed = Attribute("""
A stable value associated with this server which a client can use as an
input to a lease secret generation function.
""")
def connect_to(tub, got_connection):
"""
Attempt to establish and maintain a connection to the server.
:param Tub tub: A Foolscap Tub from which the connection is to
originate.
:param got_connection: A one-argument callable which is called with a
Foolscap ``RemoteReference`` when a connection is established.
This may be called multiple times if the connection is lost and
then re-established.
:return foolscap.reconnector.Reconnector: An object which manages the
connection and reconnection attempts.
"""
@implementer(IFoolscapStorageServer)
@attr.s(frozen=True)
class _FoolscapStorage(object):
"""
Abstraction for connecting to a storage server exposed via Foolscap.
"""
nickname = attr.ib()
permutation_seed = attr.ib()
tubid = attr.ib()
storage_server = attr.ib()
_furl = attr.ib()
_short_description = attr.ib()
_long_description = attr.ib()
@property
def name(self):
return self._short_description
@ -395,18 +450,16 @@ class _AnonymousStorage(object):
return self.tubid
@classmethod
def from_announcement(cls, server_id, ann):
def from_announcement(cls, server_id, furl, ann, storage_server):
"""
Create an instance from an announcement like::
Create an instance from a fURL and an announcement like::
{"anonymous-storage-FURL": "pb://...@...",
"permutation-seed-base32": "...",
{"permutation-seed-base32": "...",
"nickname": "...",
}
*nickname* is optional.
"""
furl = str(ann["anonymous-storage-FURL"])
m = re.match(r'pb://(\w+)@', furl)
assert m, furl
tubid_s = m.group(1).lower()
@ -437,8 +490,9 @@ class _AnonymousStorage(object):
return cls(
nickname=nickname,
permutation_seed=permutation_seed,
furl=furl,
tubid=tubid,
storage_server=storage_server,
furl=furl,
short_description=short_description,
long_description=long_description,
)
@ -447,6 +501,7 @@ class _AnonymousStorage(object):
return tub.connectTo(self._furl, got_connection)
@implementer(IFoolscapStorageServer)
class _NullStorage(object):
"""
Abstraction for *not* communicating with a storage server of a type with
@ -455,6 +510,8 @@ class _NullStorage(object):
nickname = ""
permutation_seed = hashlib.sha256("").digest()
tubid = hashlib.sha256("").digest()
storage_server = None
lease_seed = hashlib.sha256("").digest()
name = "<unsupported>"
@ -505,7 +562,8 @@ def _storage_from_plugin(config, announcement):
raise ValueError("{} not installed".format(plugin_name))
for option in storage_options:
if plugin_name == option[u"name"]:
return plugin.get_storage_client(
furl = option[u"storage-server-FURL"]
return furl, plugin.get_storage_client(
plugin_config,
option,
)
@ -548,7 +606,7 @@ class NativeStorageServer(service.MultiService):
self._tub_maker = tub_maker
self._handler_overrides = handler_overrides
self._init_from_announcement(config, ann)
self._storage = self._make_storage_system(config, ann)
self.last_connect_time = None
self.last_loss_time = None
@ -559,18 +617,52 @@ class NativeStorageServer(service.MultiService):
self._trigger_cb = None
self._on_status_changed = ObserverList()
def _init_from_announcement(self, config, ann):
def _make_storage_system(self, config, ann):
"""
:param StorageClientConfig config: Configuration specifying desired
storage client behavior.
:param dict ann: The storage announcement from the storage server we
are meant to communicate with.
:return IFoolscapStorageServer: An object enabling communication via
Foolscap with the server which generated the announcement.
"""
storage = _null_storage
# Try to match the announcement against a plugin.
try:
storage = _storage_from_plugin(config, ann)
furl, storage_server = _storage_from_plugin(config, ann)
except AnnouncementNotMatched:
if "anonymous-storage-FURL" in ann:
storage = _AnonymousStorage.from_announcement(self._server_id, ann)
self._storage = storage
# Nope.
pass
else:
return _FoolscapStorage.from_announcement(
self._server_id,
furl.encode("utf-8"),
ann,
storage_server,
)
# Try to match the announcement against the anonymous access scheme.
try:
furl = ann[u"anonymous-storage-FURL"]
except KeyError:
# Nope
pass
else:
# Pass in an accessor for our _rref attribute. The value of the
# attribute may change over time as connections are lost and
# re-established. The _StorageServer should always be able to get
# the most up-to-date value.
storage_server = _StorageServer(get_rref=self.get_rref)
return _FoolscapStorage.from_announcement(
self._server_id,
furl.encode("utf-8"),
ann,
storage_server,
)
# Nothing matched so we can't talk to this server.
return _null_storage
def get_permutation_seed(self):
return self._storage.permutation_seed
@ -678,11 +770,7 @@ class NativeStorageServer(service.MultiService):
"""
if self._rref is None:
return None
# Pass in an accessor for our _rref attribute. The value of the
# attribute may change over time as connections are lost and
# re-established. The _StorageServer should always be able to get the
# most up-to-date value.
return _StorageServer(get_rref=self.get_rref)
return self._storage.storage_server
def _lost(self):
log.msg(format="lost connection to %(name)s", name=self.get_name(),

46
src/allmydata/test/test_storage_client.py
View File

@ -5,6 +5,10 @@ from fixtures import (
TempDir,
)
from zope.interface.verify import (
verifyObject,
)
from twisted.application.service import (
Service,
)
@ -33,8 +37,10 @@ from allmydata.client import (
create_client_from_config,
)
from allmydata.storage_client import (
IFoolscapStorageServer,
NativeStorageServer,
StorageFarmBroker,
_FoolscapStorage,
_NullStorage,
)
from allmydata.interfaces import (
@ -250,7 +256,45 @@ storage.plugins = tahoe-lafs-dummy-v1
}
self.publish(server_id, ann)
storage = self.get_storage(server_id, self.node)
self.assertIsInstance(storage, DummyStorageClient)
self.assertTrue(
verifyObject(
IFoolscapStorageServer,
storage,
),
)
self.assertIsInstance(storage.storage_server, DummyStorageClient)
class FoolscapStorageServers(unittest.TestCase):
"""
Tests for implementations of ``IFoolscapStorageServer``.
"""
def test_null_provider(self):
"""
Instances of ``_NullStorage`` provide ``IFoolscapStorageServer``.
"""
self.assertTrue(
verifyObject(
IFoolscapStorageServer,
_NullStorage(),
),
)
def test_foolscap_provider(self):
"""
Instances of ``_FoolscapStorage`` provide ``IFoolscapStorageServer``.
"""
self.assertTrue(
verifyObject(
IFoolscapStorageServer,
_FoolscapStorage.from_announcement(
u"server-id",
SOME_FURL,
{u"permutation-seed-base32": base32.b2a(b"permutationseed")},
object(),
),
),
)
class TestStorageFarmBroker(unittest.TestCase):