git-annex/Logs/Transfer.hs
Joey Hess 3887432c54 fixes for transfer resume
Fix resuming of downloads, which do not have a transfer info file to read.

When checking upload progress, use the MVar, rather than re-reading
the info file.

Catch exceptions in the transfer action. Required a tryAnnex.
2012-09-24 13:18:16 -04:00

319 lines
11 KiB
Haskell

{- git-annex transfer information files and lock files
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Logs.Transfer where
import Common.Annex
import Annex.Perms
import Annex.Exception
import qualified Git
import Types.Remote
import Types.Key
import Utility.Percentage
import System.Posix.Types
import Data.Time.Clock
import Data.Time.Clock.POSIX
import Data.Time
import System.Locale
import Control.Concurrent
{- Enough information to uniquely identify a transfer, used as the filename
- of the transfer information file. -}
data Transfer = Transfer
{ transferDirection :: Direction
, transferUUID :: UUID
, transferKey :: Key
}
deriving (Eq, Ord, Read, Show)
{- Information about a Transfer, stored in the transfer information file.
-
- Note that the associatedFile may not correspond to a file in the local
- git repository. It's some file, possibly relative to some directory,
- of some repository, that was acted on to initiate the transfer.
-}
data TransferInfo = TransferInfo
{ startedTime :: Maybe POSIXTime
, transferPid :: Maybe ProcessID
, transferTid :: Maybe ThreadId
, transferRemote :: Maybe Remote
, bytesComplete :: Maybe Integer
, associatedFile :: Maybe FilePath
, transferPaused :: Bool
}
deriving (Show, Eq, Ord)
stubTransferInfo :: TransferInfo
stubTransferInfo = TransferInfo Nothing Nothing Nothing Nothing Nothing Nothing False
data Direction = Upload | Download
deriving (Eq, Ord, Read, Show)
showLcDirection :: Direction -> String
showLcDirection Upload = "upload"
showLcDirection Download = "download"
readLcDirection :: String -> Maybe Direction
readLcDirection "upload" = Just Upload
readLcDirection "download" = Just Download
readLcDirection _ = Nothing
{- Transfers that will accomplish the same task. -}
equivilantTransfer :: Transfer -> Transfer -> Bool
equivilantTransfer t1 t2
| transferDirection t1 == Download && transferDirection t2 == Download &&
transferKey t1 == transferKey t2 = True
| otherwise = t1 == t2
percentComplete :: Transfer -> TransferInfo -> Maybe Percentage
percentComplete (Transfer { transferKey = key }) info =
percentage <$> keySize key <*> Just (fromMaybe 0 $ bytesComplete info)
type RetryDecider = TransferInfo -> TransferInfo -> Bool
noRetry :: RetryDecider
noRetry _ _ = False
{- Retries a transfer when it fails, as long as the failed transfer managed
- to send some data. -}
forwardRetry :: RetryDecider
forwardRetry old new = bytesComplete old < bytesComplete new
upload :: UUID -> Key -> AssociatedFile -> RetryDecider -> (MeterUpdate -> Annex Bool) -> Annex Bool
upload u key = runTransfer (Transfer Upload u key)
download :: UUID -> Key -> AssociatedFile -> RetryDecider -> Annex Bool -> Annex Bool
download u key file shouldretry a = runTransfer (Transfer Download u key) file shouldretry (const a)
{- Runs a transfer action. Creates and locks the lock file while the
- action is running, and stores info in the transfer information
- file. Will throw an error if the transfer is already in progress.
-
- If the transfer action returns False, the transfer info is
- left in the failedTransferDir.
-}
runTransfer :: Transfer -> Maybe FilePath -> RetryDecider -> (MeterUpdate -> Annex Bool) -> Annex Bool
runTransfer t file shouldretry a = do
info <- liftIO $ startTransferInfo file
(meter, tfile, metervar) <- mkProgressUpdater t info
mode <- annexFileMode
ok <- retry info metervar $
bracketIO (prep tfile mode info) (cleanup tfile) (a meter)
unless ok $ failed info
return ok
where
prep tfile mode info = do
fd <- openFd (transferLockFile tfile) ReadWrite (Just mode)
defaultFileFlags { trunc = True }
locked <- catchMaybeIO $
setLock fd (WriteLock, AbsoluteSeek, 0, 0)
when (locked == Nothing) $
error $ "transfer already in progress"
writeTransferInfoFile info tfile
return fd
cleanup tfile fd = do
void $ tryIO $ removeFile tfile
void $ tryIO $ removeFile $ transferLockFile tfile
closeFd fd
failed info = do
failedtfile <- fromRepo $ failedTransferFile t
createAnnexDirectory $ takeDirectory failedtfile
liftIO $ writeTransferInfoFile info failedtfile
retry oldinfo metervar run = do
v <- tryAnnex run
case v of
Right b -> return b
Left _ -> do
b <- getbytescomplete metervar
let newinfo = oldinfo { bytesComplete = Just b }
if shouldretry oldinfo newinfo
then retry newinfo metervar run
else return False
getbytescomplete metervar
| transferDirection t == Upload =
liftIO $ readMVar metervar
| otherwise = do
f <- fromRepo $ gitAnnexTmpLocation (transferKey t)
liftIO $ catchDefaultIO 0 $
fromIntegral . fileSize
<$> getFileStatus f
{- Generates a callback that can be called as transfer progresses to update
- the transfer info file. Also returns the file it'll be updating, and a
- MVar that can be used to read the number of bytesComplete. -}
mkProgressUpdater :: Transfer -> TransferInfo -> Annex (MeterUpdate, FilePath, MVar Integer)
mkProgressUpdater t info = do
tfile <- fromRepo $ transferFile t
createAnnexDirectory $ takeDirectory tfile
mvar <- liftIO $ newMVar 0
return (liftIO . updater tfile mvar, tfile, mvar)
where
updater tfile mvar bytes = modifyMVar_ mvar $ \oldbytes -> do
if (bytes - oldbytes >= mindelta)
then do
let info' = info { bytesComplete = Just bytes }
writeTransferInfoFile info' tfile
return bytes
else return oldbytes
{- The minimum change in bytesComplete that is worth
- updating a transfer info file for is 1% of the total
- keySize, rounded down. -}
mindelta = case keySize (transferKey t) of
Just sz -> sz `div` 100
Nothing -> 100 * 1024 -- arbitrarily, 100 kb
startTransferInfo :: Maybe FilePath -> IO TransferInfo
startTransferInfo file = TransferInfo
<$> (Just . utcTimeToPOSIXSeconds <$> getCurrentTime)
<*> pure Nothing -- pid not stored in file, so omitted for speed
<*> pure Nothing -- tid ditto
<*> pure Nothing -- not 0; transfer may be resuming
<*> pure Nothing
<*> pure file
<*> pure False
{- If a transfer is still running, returns its TransferInfo. -}
checkTransfer :: Transfer -> Annex (Maybe TransferInfo)
checkTransfer t = do
mode <- annexFileMode
tfile <- fromRepo $ transferFile t
mfd <- liftIO $ catchMaybeIO $
openFd (transferLockFile tfile) ReadOnly (Just mode) defaultFileFlags
case mfd of
Nothing -> return Nothing -- failed to open file; not running
Just fd -> do
locked <- liftIO $
getLock fd (WriteLock, AbsoluteSeek, 0, 0)
liftIO $ closeFd fd
case locked of
Nothing -> return Nothing
Just (pid, _) -> liftIO $ catchDefaultIO Nothing $
readTransferInfoFile (Just pid) tfile
{- Gets all currently running transfers. -}
getTransfers :: Annex [(Transfer, TransferInfo)]
getTransfers = do
transfers <- catMaybes . map parseTransferFile . concat <$> findfiles
infos <- mapM checkTransfer transfers
return $ map (\(t, Just i) -> (t, i)) $
filter running $ zip transfers infos
where
findfiles = liftIO . mapM dirContentsRecursive
=<< mapM (fromRepo . transferDir)
[Download, Upload]
running (_, i) = isJust i
{- Gets failed transfers for a given remote UUID. -}
getFailedTransfers :: UUID -> Annex [(Transfer, TransferInfo)]
getFailedTransfers u = catMaybes <$> (liftIO . getpairs =<< concat <$> findfiles)
where
getpairs = mapM $ \f -> do
let mt = parseTransferFile f
mi <- readTransferInfoFile Nothing f
return $ case (mt, mi) of
(Just t, Just i) -> Just (t, i)
_ -> Nothing
findfiles = liftIO . mapM dirContentsRecursive
=<< mapM (fromRepo . failedTransferDir u)
[Download, Upload]
removeFailedTransfer :: Transfer -> Annex ()
removeFailedTransfer t = do
f <- fromRepo $ failedTransferFile t
liftIO $ void $ tryIO $ removeFile f
{- The transfer information file to use for a given Transfer. -}
transferFile :: Transfer -> Git.Repo -> FilePath
transferFile (Transfer direction u key) r = transferDir direction r
</> filter (/= '/') (fromUUID u)
</> keyFile key
{- The transfer information file to use to record a failed Transfer -}
failedTransferFile :: Transfer -> Git.Repo -> FilePath
failedTransferFile (Transfer direction u key) r = failedTransferDir u direction r
</> keyFile key
{- The transfer lock file corresponding to a given transfer info file. -}
transferLockFile :: FilePath -> FilePath
transferLockFile infofile = let (d,f) = splitFileName infofile in
combine d ("lck." ++ f)
{- Parses a transfer information filename to a Transfer. -}
parseTransferFile :: FilePath -> Maybe Transfer
parseTransferFile file
| "lck." `isPrefixOf` (takeFileName file) = Nothing
| otherwise = case drop (length bits - 3) bits of
[direction, u, key] -> Transfer
<$> readLcDirection direction
<*> pure (toUUID u)
<*> fileKey key
_ -> Nothing
where
bits = splitDirectories file
writeTransferInfoFile :: TransferInfo -> FilePath -> IO ()
writeTransferInfoFile info tfile = do
h <- openFile tfile WriteMode
fileEncoding h
hPutStr h $ writeTransferInfo info
hClose h
{- File format is a header line containing the startedTime and any
- bytesComplete value. Followed by a newline and the associatedFile.
-
- The transferPid is not included; instead it is obtained by looking
- at the process that locks the file.
-}
writeTransferInfo :: TransferInfo -> String
writeTransferInfo info = unlines
[ (maybe "" show $ startedTime info) ++
(maybe "" (\b -> " " ++ show b) $ bytesComplete info)
, fromMaybe "" $ associatedFile info -- comes last; arbitrary content
]
readTransferInfoFile :: (Maybe ProcessID) -> FilePath -> IO (Maybe TransferInfo)
readTransferInfoFile mpid tfile = catchDefaultIO Nothing $ do
h <- openFile tfile ReadMode
fileEncoding h
hClose h `after` (readTransferInfo mpid <$> hGetContentsStrict h)
readTransferInfo :: (Maybe ProcessID) -> String -> Maybe TransferInfo
readTransferInfo mpid s = TransferInfo
<$> time
<*> pure mpid
<*> pure Nothing
<*> pure Nothing
<*> bytes
<*> pure (if null filename then Nothing else Just filename)
<*> pure False
where
(firstline, filename) = separate (== '\n') s
bits = split " " firstline
numbits = length bits
time = if numbits > 0
then Just <$> parsePOSIXTime (bits !! 0)
else pure Nothing
bytes = if numbits > 1
then Just <$> readish (bits !! 1)
else pure Nothing
parsePOSIXTime :: String -> Maybe POSIXTime
parsePOSIXTime s = utcTimeToPOSIXSeconds
<$> parseTime defaultTimeLocale "%s%Qs" s
{- The directory holding transfer information files for a given Direction. -}
transferDir :: Direction -> Git.Repo -> FilePath
transferDir direction r = gitAnnexTransferDir r </> showLcDirection direction
{- The directory holding failed transfer information files for a given
- Direction and UUID -}
failedTransferDir :: UUID -> Direction -> Git.Repo -> FilePath
failedTransferDir u direction r = gitAnnexTransferDir r
</> "failed"
</> showLcDirection direction
</> filter (/= '/') (fromUUID u)