8d32d54320
When multiple downloads of a key are queued, it starts the first, but leaves the other downloads in the queue. This ensures that we don't lose a queued download if the one that got started failed.
99 lines
3 KiB
Haskell
99 lines
3 KiB
Haskell
{- git-annex assistant data transferrer thread
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Assistant.Threads.Transferrer where
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import Assistant.Common
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import Assistant.ThreadedMonad
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import Assistant.DaemonStatus
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import Assistant.TransferQueue
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import Assistant.TransferSlots
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import Assistant.Alert
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import Logs.Transfer
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import Logs.Location
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import Annex.Content
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import qualified Remote
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import Types.Key
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import Locations.UserConfig
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import System.Process (create_group)
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thisThread :: ThreadName
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thisThread = "Transferrer"
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{- For now only one transfer is run at a time. -}
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maxTransfers :: Int
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maxTransfers = 1
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{- Dispatches transfers from the queue. -}
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transfererThread :: ThreadState -> DaemonStatusHandle -> TransferQueue -> TransferSlots -> IO ()
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transfererThread st dstatus transferqueue slots = go =<< readProgramFile
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where
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go program = forever $ inTransferSlot dstatus slots $
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maybe (return Nothing) (uncurry $ startTransfer st dstatus program)
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=<< getNextTransfer transferqueue dstatus notrunning
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{- Skip transfers that are already running. -}
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notrunning i = startedTime i == Nothing
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{- By the time this is called, the daemonstatis's transfer map should
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- already have been updated to include the transfer. -}
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startTransfer :: ThreadState -> DaemonStatusHandle -> FilePath -> Transfer -> TransferInfo -> TransferGenerator
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startTransfer st dstatus program t info = case (transferRemote info, associatedFile info) of
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(Just remote, Just file) -> ifM (runThreadState st $ shouldTransfer t info)
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( do
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debug thisThread [ "Transferring:" , show t ]
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notifyTransfer dstatus
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return $ Just (t, info, transferprocess remote file)
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, do
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debug thisThread [ "Skipping unnecessary transfer:" , show t ]
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void $ removeTransfer dstatus t
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return Nothing
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)
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_ -> return Nothing
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where
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direction = transferDirection t
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isdownload = direction == Download
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transferprocess remote file = void $ do
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(_, _, _, pid)
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<- createProcess (proc program $ toCommand params)
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{ create_group = True }
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ok <- (==) ExitSuccess <$> waitForProcess pid
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when ok $ void $
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addAlert dstatus $
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makeAlertFiller ok $
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transferFileAlert direction ok file
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where
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params =
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[ Param "transferkey"
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, Param $ key2file $ transferKey t
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, Param $ if isdownload
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then "--from"
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else "--to"
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, Param $ Remote.name remote
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, Param "--file"
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, File file
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]
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{- Checks if the file to download is already present, or the remote
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- being uploaded to isn't known to have the file. -}
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shouldTransfer :: Transfer -> TransferInfo -> Annex Bool
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shouldTransfer t info
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| transferDirection t == Download =
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not <$> inAnnex key
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| transferDirection t == Upload =
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{- Trust the location log to check if the
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- remote already has the key. This avoids
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- a roundtrip to the remote. -}
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case transferRemote info of
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Nothing -> return False
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Just remote ->
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notElem (Remote.uuid remote)
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<$> loggedLocations key
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| otherwise = return False
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where
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key = transferKey t
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