[tahoe-lafs-trac-stream] [Tahoe-LAFS] #467: allow the user to specify which servers a given gateway will use for uploads

[Tahoe-LAFS]

#467: allow the user to specify which servers a given gateway will use for
uploads
-------------------------+-------------------------------------------------
     Reporter:  warner   |      Owner:  leif
         Type:           |     Status:  new
  enhancement            |
     Priority:  major    |  Milestone:  1.12.0
    Component:  code-    |    Version:  1.1.0
  peerselection          |   Keywords:  availability preservation cache
   Resolution:           |  anti-censorship placement backend rollback add-
Launchpad Bug:           |  only
-------------------------+-------------------------------------------------

Comment (by warner):

 As mentioned on IRC, I'd like to avoid having this code synthesize a fake
 "serverid". In particular I want to maintain the contract that
 `NativeStorageServer` (via storage_client) gets a `key_s=` argument that
 is either the full !ed25519 pubkey, or None.

 So I'd suggest:

 * change the stored (YAML) data format. It current stores the full
 announcement dictionary (plus the added 'serverid' key). Instead, I'd
 suggest a two-level structure, where the top dictionary has a `key_s` key
 (the value of which is exactly the first argument passed to
 `StorageFarmBroker._got_announcement`: either a full "v0-"-prefixed
 pubkey, or None), and an `ann` key (the value of which is the full
 announcement dictionary).
 * remove the `versionid` changes

 `NativeStorageServer` isn't using the `key_s=` argument for anything other
 than human-oriented descriptions yet, but I'd like to be consistent about
 `key_s` being a real pubkey (if available) so that we could use it
 reliably for something else in the future. Like maybe exchanging gossip
 with other clients about server reliability, for which having a pubkey to
 verify against would be handy.

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/467#comment:46>
Tahoe-LAFS <https://Tahoe-LAFS.org>
secure decentralized storage