This stores the sequence number in BASEDIR/announcement-seqnum, and
increments it each time any service is published (every service
announcement is regenerated with the new sequence number). As everyone
knows, time is an illusion, and occasionally goes backwards, so a
counter is generally safer (and reveals less information about the
node).
Later, we'll improve the introducer client to tolerate rollbacks (where,
perhaps due to a VM being restarted from an earlier checkpoint, the
stored sequence number reverts to an earlier version).
This significantly cleans up the IntroducerServer web-status renderers.
Instead of poking around in the introducer's internals, now the web-status
renderers get clean AnnouncementDescriptor and SubscriberDescriptor
objects. They are still somewhat foolscap-centric, but will provide a clean
abstraction boundary for future improvements.
The specific #1721 bug was that old (V1) subscribers were handled by
wrapping their RemoteReference in a special WrapV1SubscriberInV2Interface
object, but the web-status display was trying to peek inside the object to
learn what host+port it was associated with, and the wrapper did not proxy
those extra attributes.
A test was added to test_introducer to make sure the introweb page renders
properly and at least contains the nicknames of both the V1 and V2 clients.
This introduces new client and server halves to the Introducer (renaming the
old one with a _V1 suffix). Both have fallbacks to accomodate talking to a
different version: the publishing client switches on whether the server's
.get_version() advertises V2 support, the server switches on which
subscription method was invoked by the subscribing client.
The V2 protocol sends a three-tuple of (serialized announcement dictionary,
signature, pubkey) for each announcement. The V2 server dispatches messages
to subscribers according to the service-name, and throws errors for invalid
signatures, but does not otherwise examine the messages. The V2 receiver's
subscription callback will receive a (serverid, ann_dict) pair. The
'serverid' will be equal to the pubkey if all of the following are true:
the originating client is V2, and was told a privkey to use
the announcement went through a V2 server
the signature is valid
If not, 'serverid' will be equal to the tubid portion of the announced FURL,
as was the case for V1 receivers.
Servers will create a keypair if one does not exist yet, stored in
private/server.privkey .
The signed announcement dictionary puts the server FURL in a key named
"anonymous-storage-FURL", which anticipates upcoming Accounting-related
changes in the server advertisements. It also provides a key named
"permutation-seed-base32" to tell clients what permutation seed to use. This
is computed at startup, using tubid if there are existing shares, otherwise
the pubkey, to retain share-order compatibility for existing servers.
It is currently hardcoded in setup.py to be 'allmydata-tahoe'. Ticket #556 is to make it configurable by a runtime command-line argument to setup.py: "--appname=foo", but I suddenly wondered if we really wanted that and at the same time realized that we don't need that for tahoe-1.3.0 release, so this patch just hardcodes it in setup.py.
setup.py inspects a file named 'src/allmydata/_appname.py' and assert that it contains the string "__appname__ = 'allmydata-tahoe'", and creates it if it isn't already present. src/allmydata/__init__.py import _appname and reads __appname__ from it. The rest of the Python code imports allmydata and inspects "allmydata.__appname__", although actually every use it uses "allmydata.__full_version__" instead, where "allmydata.__full_version__" is created in src/allmydata/__init__.py to be:
__full_version__ = __appname + '-' + str(__version__).
All the code that emits an "application version string" when describing what version of a protocol it supports (introducer server, storage server, upload helper), or when describing itself in general (introducer client), usese allmydata.__full_version__.
This fixes ticket #556 at least well enough for tahoe-1.3.0 release.
