The underlying issue is recorded in #211: one corrupt share in a query
response will cause us to ignore the remaining shares in that response, even
if they are good. In our tests (with N=10 but only 5 peers), this can leave
us with too few shares to recover the file.
The temporary workaround is to use 10 peers, to make sure we never get
multiple shares per response. The real fix will be to fix the control flow.
This fixes#209.
* use new decentralized directories everywhere instead of old centralized directories
* provide UI to them through the web server
* provide UI to them through the CLI
* update unit tests to simulate decentralized mutable directories in order to test other components that rely on them
* remove the notion of a "vdrive server" and a client thereof
* remove the notion of a "public vdrive", which was a directory that was centrally published/subscribed automatically by the tahoe node (you can accomplish this manually by making a directory and posting the URL to it on your web site, for example)
* add a notion of "wait_for_numpeers" when you need to publish data to peers, which is how many peers should be attached before you start. The default is 1.
* add __repr__ for filesystem nodes (note: these reprs contain a few bits of the secret key!)
* fix a few bugs where we used to equate "mutable" with "not read-only". Nowadays all directories are mutable, but some might be read-only (to you).
* fix a few bugs where code wasn't aware of the new general-purpose metadata dict the comes with each filesystem edge
* sundry fixes to unit tests to adjust to the new directories, e.g. don't assume that every share on disk belongs to a chk file.
This creates a Referenceable object that will eventually be able to publish
log events to a remote subscriber (at present all it can do is provide
version information). The FURL for this logport is written to 'logport.furl'.
In addition, if a file named 'log_gatherer.furl' is present, the given target
will be contacted and offered access to the logport. This can be used by a
centralized logging agent to subscribe to logs, e.g. from all the nodes in a
centrally-maintained storage grid. (think syslog -r, but with all the
security properties of FURLs, and permitting non-printable strings and
structured data).
Once this framework matures a bit, it will be moved into Foolscap.
The URI typenames need revision, and only a few dirnode methods are
implemented. Filenodes are non-functional, but URI/key-management is in
place. There are a lot of classes with names like "NewDirectoryNode" that
will need to be rename once we decide what (if any) backwards compatibility
want to retain.
