[tahoe-lafs-trac-stream] [Tahoe-LAFS] #3762: Determine what the new storage client HTTP protocol's version verb returns

[Tahoe-LAFS]

#3762: Determine what the new storage client HTTP protocol's version verb returns
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     Reporter:  itamarst  |      Owner:
         Type:  task      |     Status:  new
     Priority:  normal    |  Milestone:  HTTP Storage Protocol
    Component:  unknown   |    Version:  n/a
   Resolution:            |   Keywords:
Launchpad Bug:            |
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Comment (by exarkun):

 In my Haskell server, I modeled the Foolscap version response like this:

 {{{
 type ApplicationVersion = String

 data Version1Parameters = Version1Parameters
   { maximumImmutableShareSize                 :: Size
   , maximumMutableShareSize                   :: Size
   , availableSpace                            :: Size
   , toleratesImmutableReadOverrun             :: Bool
   , deleteMutableSharesWithZeroLengthWritev   :: Bool
   , fillsHolesWithZeroBytes                   :: Bool
   , preventsReadPastEndOfShareData            :: Bool
   , httpProtocolAvailable                     :: Bool
   } deriving (Show, Eq, Generic)

 data Version = Version
   { applicationVersion :: ApplicationVersion
   , parameters         :: Version1Parameters
   } deriving (Show, Eq, Generic)
 }}}

 I believe `httpProtocolAvailable` was an addition of my own and I think
 that we may since have decided not to try to advertise GBS that way.  I
 think the rest of the fields correspond to what the current implementation
 does.

 It ends up being a lot more than just a "version".  Oh well?

 Most of these fields are really descriptions of behaviors of the storage
 functionality of the server that might change (in practice I think only
 `availableSpace` is particularly dynamic - all of the bools changed from
 False to True or vice versa in some particular release and then never
 again and the other sizes have some default that no one ever bothers to
 override?).  But there is that `ApplicationVersion` string.

 Or, maybe more helpful is this fragment of Python that constructs the
 value:

 {{{
         version = { b"http://allmydata.org/tahoe/protocols/storage/v1" :
                     { b"maximum-immutable-share-size": remaining_space,
                       b"maximum-mutable-share-size":
 MAX_MUTABLE_SHARE_SIZE,
                       b"available-space": remaining_space,
                       b"tolerates-immutable-read-overrun": True,
                       b"delete-mutable-shares-with-zero-length-writev":
 True,
                       b"fills-holes-with-zero-bytes": True,
                       b"prevents-read-past-end-of-share-data": True,
                       },
                     b"application-version":
 allmydata.__full_version__.encode("utf-8"),
                     }
 }}}

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3762#comment:1>
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