git-annex/Remote/External.hs
2013-12-27 13:17:22 -04:00

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{- External special remote interface.
-
- Copyright 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.External (remote) where
import Remote.External.Types
import qualified Annex
import Common.Annex
import Types.Remote
import qualified Git
import Config
import Remote.Helper.Special
import Remote.Helper.Encryptable
import Crypto
import Utility.Metered
import Logs.Transfer
import Config.Cost
import Annex.Content
import Annex.UUID
import Annex.Exception
import Control.Concurrent.STM
import System.Process (std_in, std_out, std_err)
import System.Log.Logger (debugM)
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as L
remote :: RemoteType
remote = RemoteType {
typename = "external",
enumerate = findSpecialRemotes "externaltype",
generate = gen,
setup = externalSetup
}
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
gen r u c gc = do
external <- newExternal externaltype c
Annex.addCleanup (fromUUID u) $ stopExternal external
cst <- getCost external r gc
return $ Just $ encryptableRemote c
(storeEncrypted external $ getGpgEncParams (c,gc))
(retrieveEncrypted external)
Remote {
uuid = u,
cost = cst,
name = Git.repoDescribe r,
storeKey = store external,
retrieveKeyFile = retrieve external,
retrieveKeyFileCheap = \_ _ -> return False,
removeKey = remove external,
hasKey = checkPresent external,
hasKeyCheap = False,
whereisKey = Nothing,
remoteFsck = Nothing,
repairRepo = Nothing,
config = c,
localpath = Nothing,
repo = r,
gitconfig = gc,
readonly = False,
globallyAvailable = False,
remotetype = remote
}
where
externaltype = fromMaybe (error "missing externaltype") $ remoteAnnexExternalType gc
externalSetup :: Maybe UUID -> RemoteConfig -> Annex (RemoteConfig, UUID)
externalSetup mu c = do
u <- maybe (liftIO genUUID) return mu
let externaltype = fromMaybe (error "Specify externaltype=") $
M.lookup "externaltype" c
c' <- encryptionSetup c
external <- newExternal externaltype c'
handleRequest external INITREMOTE Nothing $ \resp -> case resp of
INITREMOTE_SUCCESS -> Just noop
INITREMOTE_FAILURE errmsg -> Just $ error errmsg
_ -> Nothing
c'' <- liftIO $ atomically $ readTMVar $ externalConfig external
gitConfigSpecialRemote u c'' "externaltype" externaltype
return (c'', u)
store :: External -> Key -> AssociatedFile -> MeterUpdate -> Annex Bool
store external k _f p = sendAnnex k rollback $ \f ->
storeHelper external k f p
where
rollback = void $ remove external k
storeEncrypted :: External -> [CommandParam] -> (Cipher, Key) -> Key -> MeterUpdate -> Annex Bool
storeEncrypted external gpgOpts (cipher, enck) k p = withTmp enck $ \tmp ->
sendAnnex k rollback $ \src -> do
liftIO $ encrypt gpgOpts cipher (feedFile src) $
readBytes $ L.writeFile tmp
storeHelper external enck tmp p
where
rollback = void $ remove external enck
storeHelper :: External -> Key -> FilePath -> MeterUpdate -> Annex Bool
storeHelper external k f p = safely $
handleRequest external (TRANSFER Upload k f) (Just p) $ \resp ->
case resp of
TRANSFER_SUCCESS Upload k' | k == k' ->
Just $ return True
TRANSFER_FAILURE Upload k' errmsg | k == k' ->
Just $ do
warning errmsg
return False
_ -> Nothing
retrieve :: External -> Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Bool
retrieve external k _f d p = retrieveHelper external k d p
retrieveEncrypted :: External -> (Cipher, Key) -> Key -> FilePath -> MeterUpdate -> Annex Bool
retrieveEncrypted external (cipher, enck) _ f p = withTmp enck $ \tmp ->
ifM (retrieveHelper external enck tmp p)
( liftIO $ catchBoolIO $ do
decrypt cipher (feedFile tmp) $
readBytes $ L.writeFile f
return True
, return False
)
retrieveHelper :: External -> Key -> FilePath -> MeterUpdate -> Annex Bool
retrieveHelper external k d p = safely $
handleRequest external (TRANSFER Download k d) (Just p) $ \resp ->
case resp of
TRANSFER_SUCCESS Download k'
| k == k' -> Just $ return True
TRANSFER_FAILURE Download k' errmsg
| k == k' -> Just $ do
warning errmsg
return False
_ -> Nothing
remove :: External -> Key -> Annex Bool
remove external k = safely $
handleRequest external (REMOVE k) Nothing $ \resp ->
case resp of
REMOVE_SUCCESS k'
| k == k' -> Just $ return True
REMOVE_FAILURE k' errmsg
| k == k' -> Just $ do
warning errmsg
return False
_ -> Nothing
checkPresent :: External -> Key -> Annex (Either String Bool)
checkPresent external k = either (Left . show) id <$> tryAnnex go
where
go = handleRequest external (CHECKPRESENT k) Nothing $ \resp ->
case resp of
CHECKPRESENT_SUCCESS k'
| k' == k -> Just $ return $ Right True
CHECKPRESENT_FAILURE k'
| k' == k -> Just $ return $ Right False
CHECKPRESENT_UNKNOWN k' errmsg
| k' == k -> Just $ return $ Left errmsg
_ -> Nothing
safely :: Annex Bool -> Annex Bool
safely a = go =<< tryAnnex a
where
go (Right r) = return r
go (Left e) = do
warning $ show e
return False
{- Sends a Request to the external remote, and waits for it to generate
- a Response. That is fed into the responsehandler, which should return
- the action to run for it (or Nothing if there's a protocol error).
-
- While the external remote is processing the Request, it may send
- any number of RemoteRequests, that are handled here.
-
- Only one request can be made at a time, so locking is used.
-
- May throw exceptions, for example on protocol errors.
-}
handleRequest :: External -> Request -> Maybe MeterUpdate -> (Response -> Maybe (Annex a)) -> Annex a
handleRequest external req mp responsehandler =
withExternalLock external $ \lck ->
handleRequest' lck external req mp responsehandler
handleRequest' :: ExternalLock -> External -> Request -> Maybe MeterUpdate -> (Response -> Maybe (Annex a)) -> Annex a
handleRequest' lck external req mp responsehandler = do
when (needsPREPARE req) $
checkPrepared lck external
sendMessage lck external req
loop
where
loop = receiveMessage lck external responsehandler
(\rreq -> Just $ handleRemoteRequest rreq >> loop)
(\msg -> Just $ handleAsyncMessage msg >> loop)
handleRemoteRequest (PROGRESS bytesprocessed) =
maybe noop (\a -> liftIO $ a bytesprocessed) mp
handleRemoteRequest (DIRHASH k) =
sendMessage lck external (VALUE $ hashDirMixed k)
handleRemoteRequest (SETCONFIG setting value) =
liftIO $ atomically $ do
let v = externalConfig external
m <- takeTMVar v
putTMVar v $ M.insert setting value m
handleRemoteRequest (GETCONFIG setting) = do
value <- fromMaybe "" . M.lookup setting
<$> liftIO (atomically $ readTMVar $ externalConfig external)
sendMessage lck external (VALUE value)
handleRemoteRequest (VERSION _) =
sendMessage lck external (ERROR "too late to send VERSION")
handleAsyncMessage (ERROR err) = error $ "external special remote error: " ++ err
sendMessage :: Sendable m => ExternalLock -> External -> m -> Annex ()
sendMessage lck external m =
fromExternal lck external externalSend $ \h ->
liftIO $ do
protocolDebug external True line
hPutStrLn h line
where
line = unwords $ formatMessage m
{- Waits for a message from the external remote, and passes it to the
- apppropriate handler.
-
- If the handler returns Nothing, this is a protocol error.-}
receiveMessage
:: ExternalLock
-> External
-> (Response -> Maybe (Annex a))
-> (RemoteRequest -> Maybe (Annex a))
-> (AsyncMessage -> Maybe (Annex a))
-> Annex a
receiveMessage lck external handleresponse handlerequest handleasync = do
s <- fromExternal lck external externalReceive $ liftIO . hGetLine
liftIO $ protocolDebug external False s
case parseMessage s :: Maybe Response of
Just resp -> maybe (protocolError s) id (handleresponse resp)
Nothing -> case parseMessage s :: Maybe RemoteRequest of
Just req -> maybe (protocolError s) id (handlerequest req)
Nothing -> case parseMessage s :: Maybe AsyncMessage of
Just msg -> maybe (protocolError s) id (handleasync msg)
Nothing -> protocolError s
where
protocolError s = error $ "external special remote protocol error, unexpectedly received \"" ++ s ++ "\""
protocolDebug :: External -> Bool -> String -> IO ()
protocolDebug external sendto line = debugM "external" $ unwords
[ externalRemoteProgram (externalType external)
, if sendto then "<--" else "-->"
, line
]
{- Starts up the external remote if it's not yet running,
- and passes a value extracted from its state to an action.
-}
fromExternal :: ExternalLock -> External -> (ExternalState -> v) -> (v -> Annex a) -> Annex a
fromExternal lck external extractor a =
go =<< liftIO (atomically (tryReadTMVar v))
where
go (Just st) = run st
go Nothing = do
st <- startExternal $ externalType external
void $ liftIO $ atomically $ do
void $ tryReadTMVar v
putTMVar v st
{- Handle initial protocol startup; check the VERSION
- the remote sends. -}
receiveMessage lck external
(const Nothing)
(checkVersion lck external)
(const Nothing)
run st
run st = a $ extractor st
v = externalState external
{- Starts an external remote process running, but does not handle checking
- VERSION, etc. -}
startExternal :: ExternalType -> Annex ExternalState
startExternal externaltype = liftIO $ do
(Just hin, Just hout, _, pid) <- createProcess $
(proc (externalRemoteProgram externaltype) [])
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = Inherit
}
fileEncoding hin
fileEncoding hout
return $ ExternalState
{ externalSend = hin
, externalReceive = hout
, externalPid = pid
, externalPrepared = False
}
stopExternal :: External -> Annex ()
stopExternal external = liftIO $ stop =<< atomically (tryReadTMVar v)
where
stop Nothing = noop
stop (Just st) = do
void $ atomically $ tryTakeTMVar v
hClose $ externalSend st
hClose $ externalReceive st
void $ waitForProcess $ externalPid st
v = externalState external
externalRemoteProgram :: ExternalType -> String
externalRemoteProgram externaltype = "git-annex-remote-" ++ externaltype
checkVersion :: ExternalLock -> External -> RemoteRequest -> Maybe (Annex ())
checkVersion lck external (VERSION v) = Just $
if v `elem` supportedProtocolVersions
then noop
else sendMessage lck external (ERROR "unsupported VERSION")
checkVersion _ _ _ = Nothing
checkPrepared :: ExternalLock -> External -> Annex ()
checkPrepared lck external =
fromExternal lck external externalPrepared $ \prepared ->
unless prepared $
handleRequest' lck external PREPARE Nothing $ \resp ->
case resp of
PREPARE_SUCCESS -> Just noop
_ -> Nothing
{- Caches the cost in the git config to avoid needing to start up an
- external special remote every time time just to ask it what its
- cost is. -}
getCost :: External -> Git.Repo -> RemoteGitConfig -> Annex Cost
getCost external r gc = go =<< remoteCost' gc
where
go (Just c) = return c
go Nothing = do
c <- handleRequest external GETCOST Nothing $ \req -> case req of
COST c -> Just $ return c
UNSUPPORTED_REQUEST -> Just $ return expensiveRemoteCost
_ -> Nothing
setRemoteCost r c
return c