git-annex/Remote/External.hs
Joey Hess 5358fb992a
Windows: Improve handling of shebang in external special remote program, searching for the program in the PATH.
findShellCommand needs a full path to a file in order to check it for a
shebang on Windows. It was being run with only the base name of the external
special remote program, which would only work when it was in the current
directory.

This is why users in
https://github.com/DanielDent/git-annex-remote-rclone/pull/10 and elsewhere
were complaining that the previous improvements to git-annex didn't make
git-remote-rclone work on Windows.

Also, reworked checkearlytermination, which while it worked, seemed
to rely on a race condition. And, improved its error messages.

This commit was sponsored by Shane-o on Patreon.
2017-03-08 15:59:00 -04:00

536 lines
17 KiB
Haskell

{- External special remote interface.
-
- Copyright 2013-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.External (remote) where
import Remote.External.Types
import qualified Annex
import Annex.Common
import Types.Remote
import Types.CleanupActions
import Types.UrlContents
import qualified Git
import Config
import Git.Config (isTrue, boolConfig)
import Git.Env
import Remote.Helper.Special
import Remote.Helper.ReadOnly
import Remote.Helper.Messages
import Utility.Metered
import Utility.Shell
import Messages.Progress
import Types.Transfer
import Logs.PreferredContent.Raw
import Logs.RemoteState
import Logs.Web
import Config.Cost
import Annex.Content
import Annex.Url
import Annex.UUID
import Creds
import Control.Concurrent.STM
import Control.Concurrent.Async
import System.Log.Logger (debugM)
import qualified Data.Map as M
remote :: RemoteType
remote = RemoteType {
typename = "external",
enumerate = const (findSpecialRemotes "externaltype"),
generate = gen,
setup = externalSetup
}
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
gen r u c gc
-- readonly mode only downloads urls; does not use external program
| remoteAnnexReadOnly gc = do
cst <- remoteCost gc expensiveRemoteCost
mk cst GloballyAvailable
readonlyStorer
retrieveUrl
readonlyRemoveKey
(checkKeyUrl r)
Nothing
Nothing
Nothing
| otherwise = do
external <- newExternal externaltype u c gc
Annex.addCleanup (RemoteCleanup u) $ stopExternal external
cst <- getCost external r gc
avail <- getAvailability external r gc
mk cst avail
(store external)
(retrieve external)
(remove external)
(checkKey external)
(Just (whereis external))
(Just (claimurl external))
(Just (checkurl external))
where
mk cst avail tostore toretrieve toremove tocheckkey towhereis toclaimurl tocheckurl = do
let rmt = Remote
{ uuid = u
, cost = cst
, name = Git.repoDescribe r
, storeKey = storeKeyDummy
, retrieveKeyFile = retreiveKeyFileDummy
, retrieveKeyFileCheap = \_ _ _ -> return False
, removeKey = removeKeyDummy
, lockContent = Nothing
, checkPresent = checkPresentDummy
, checkPresentCheap = False
, whereisKey = towhereis
, remoteFsck = Nothing
, repairRepo = Nothing
, config = c
, localpath = Nothing
, repo = r
, gitconfig = gc
, readonly = False
, availability = avail
, remotetype = remote
, mkUnavailable = gen r u c $
gc { remoteAnnexExternalType = Just "!dne!" }
, getInfo = return [("externaltype", externaltype)]
, claimUrl = toclaimurl
, checkUrl = tocheckurl
}
return $ Just $ specialRemote c
(simplyPrepare tostore)
(simplyPrepare toretrieve)
(simplyPrepare toremove)
(simplyPrepare tocheckkey)
rmt
externaltype = fromMaybe (giveup "missing externaltype") (remoteAnnexExternalType gc)
externalSetup :: SetupStage -> Maybe UUID -> Maybe CredPair -> RemoteConfig -> RemoteGitConfig -> Annex (RemoteConfig, UUID)
externalSetup _ mu _ c gc = do
u <- maybe (liftIO genUUID) return mu
let externaltype = fromMaybe (giveup "Specify externaltype=") $
M.lookup "externaltype" c
(c', _encsetup) <- encryptionSetup c gc
c'' <- case M.lookup "readonly" c of
Just v | isTrue v == Just True -> do
setConfig (remoteConfig (fromJust (M.lookup "name" c)) "readonly") (boolConfig True)
return c'
_ -> do
external <- newExternal externaltype u c' gc
handleRequest external INITREMOTE Nothing $ \resp -> case resp of
INITREMOTE_SUCCESS -> Just noop
INITREMOTE_FAILURE errmsg -> Just $ giveup errmsg
_ -> Nothing
withExternalState external $
liftIO . atomically . readTVar . externalConfig
gitConfigSpecialRemote u c'' "externaltype" externaltype
return (c'', u)
store :: External -> Storer
store external = fileStorer $ \k f p ->
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 -> Retriever
retrieve external = fileRetriever $ \d k p ->
handleRequest external (TRANSFER Download k d) (Just p) $ \resp ->
case resp of
TRANSFER_SUCCESS Download k'
| k == k' -> Just $ return ()
TRANSFER_FAILURE Download k' errmsg
| k == k' -> Just $ giveup errmsg
_ -> Nothing
remove :: External -> Remover
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
checkKey :: External -> CheckPresent
checkKey external k = either giveup id <$> 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
whereis :: External -> Key -> Annex [String]
whereis external k = handleRequest external (WHEREIS k) Nothing $ \resp -> case resp of
WHEREIS_SUCCESS s -> Just $ return [s]
WHEREIS_FAILURE -> Just $ return []
UNSUPPORTED_REQUEST -> Just $ return []
_ -> Nothing
safely :: Annex Bool -> Annex Bool
safely a = go =<< tryNonAsync 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.
-
- An external remote process can only handle one request at a time.
- Concurrent requests will start up additional processes.
-
- May throw exceptions, for example on protocol errors, or
- when the repository cannot be used.
-}
handleRequest :: External -> Request -> Maybe MeterUpdate -> (Response -> Maybe (Annex a)) -> Annex a
handleRequest external req mp responsehandler =
withExternalState external $ \st ->
handleRequest' st external req mp responsehandler
handleRequest' :: ExternalState -> External -> Request -> Maybe MeterUpdate -> (Response -> Maybe (Annex a)) -> Annex a
handleRequest' st external req mp responsehandler
| needsPREPARE req = do
checkPrepared st external
go
| otherwise = go
where
go = do
sendMessage st external req
loop
loop = receiveMessage st 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) =
send $ VALUE $ hashDirMixed def k
handleRemoteRequest (DIRHASH_LOWER k) =
send $ VALUE $ hashDirLower def k
handleRemoteRequest (SETCONFIG setting value) =
liftIO $ atomically $ modifyTVar' (externalConfig st) $
M.insert setting value
handleRemoteRequest (GETCONFIG setting) = do
value <- fromMaybe "" . M.lookup setting
<$> liftIO (atomically $ readTVar $ externalConfig st)
send $ VALUE value
handleRemoteRequest (SETCREDS setting login password) = do
let v = externalConfig st
c <- liftIO $ atomically $ readTVar v
let gc = externalGitConfig external
c' <- setRemoteCredPair encryptionAlreadySetup c gc
(credstorage setting)
(Just (login, password))
void $ liftIO $ atomically $ swapTVar v c'
handleRemoteRequest (GETCREDS setting) = do
c <- liftIO $ atomically $ readTVar $ externalConfig st
let gc = externalGitConfig external
creds <- fromMaybe ("", "") <$>
getRemoteCredPair c gc (credstorage setting)
send $ CREDS (fst creds) (snd creds)
handleRemoteRequest GETUUID = send $
VALUE $ fromUUID $ externalUUID external
handleRemoteRequest GETGITDIR = send . VALUE =<< fromRepo Git.localGitDir
handleRemoteRequest (SETWANTED expr) =
preferredContentSet (externalUUID external) expr
handleRemoteRequest GETWANTED = do
expr <- fromMaybe "" . M.lookup (externalUUID external)
<$> preferredContentMapRaw
send $ VALUE expr
handleRemoteRequest (SETSTATE key state) =
setRemoteState (externalUUID external) key state
handleRemoteRequest (GETSTATE key) = do
state <- fromMaybe ""
<$> getRemoteState (externalUUID external) key
send $ VALUE state
handleRemoteRequest (SETURLPRESENT key url) =
setUrlPresent (externalUUID external) key url
handleRemoteRequest (SETURLMISSING key url) =
setUrlMissing (externalUUID external) key url
handleRemoteRequest (SETURIPRESENT key uri) =
withurl (SETURLPRESENT key) uri
handleRemoteRequest (SETURIMISSING key uri) =
withurl (SETURLMISSING key) uri
handleRemoteRequest (GETURLS key prefix) = do
mapM_ (send . VALUE) =<< getUrlsWithPrefix key prefix
send (VALUE "") -- end of list
handleRemoteRequest (DEBUG msg) = liftIO $ debugM "external" msg
handleRemoteRequest (VERSION _) =
sendMessage st external (ERROR "too late to send VERSION")
handleAsyncMessage (ERROR err) = giveup $ "external special remote error: " ++ err
send = sendMessage st external
credstorage setting = CredPairStorage
{ credPairFile = base
, credPairEnvironment = (base ++ "login", base ++ "password")
, credPairRemoteKey = Just setting
}
where
base = replace "/" "_" $ fromUUID (externalUUID external) ++ "-" ++ setting
withurl mk uri = handleRemoteRequest $ mk $
setDownloader (show uri) OtherDownloader
sendMessage :: Sendable m => ExternalState -> External -> m -> Annex ()
sendMessage st external m = liftIO $ do
protocolDebug external st True line
hPutStrLn h line
hFlush h
where
line = unwords $ formatMessage m
h = externalSend st
{- 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
:: ExternalState
-> External
-> (Response -> Maybe (Annex a))
-> (RemoteRequest -> Maybe (Annex a))
-> (AsyncMessage -> Maybe (Annex a))
-> Annex a
receiveMessage st external handleresponse handlerequest handleasync =
go =<< liftIO (catchMaybeIO $ hGetLine $ externalReceive st)
where
go Nothing = protocolError False ""
go (Just s) = do
liftIO $ protocolDebug external st False s
case parseMessage s :: Maybe Response of
Just resp -> maybe (protocolError True s) id (handleresponse resp)
Nothing -> case parseMessage s :: Maybe RemoteRequest of
Just req -> maybe (protocolError True s) id (handlerequest req)
Nothing -> case parseMessage s :: Maybe AsyncMessage of
Just msg -> maybe (protocolError True s) id (handleasync msg)
Nothing -> protocolError False s
protocolError parsed s = giveup $ "external special remote protocol error, unexpectedly received \"" ++ s ++ "\" " ++
if parsed then "(command not allowed at this time)" else "(unable to parse command)"
protocolDebug :: External -> ExternalState -> Bool -> String -> IO ()
protocolDebug external st sendto line = debugM "external" $ unwords
[ externalRemoteProgram (externalType external) ++
"[" ++ show (externalPid st) ++ "]"
, if sendto then "<--" else "-->"
, line
]
{- While the action is running, the ExternalState provided to it will not
- be available to any other calls.
-
- Starts up a new process if no ExternalStates are available. -}
withExternalState :: External -> (ExternalState -> Annex a) -> Annex a
withExternalState external = bracket alloc dealloc
where
v = externalState external
alloc = do
ms <- liftIO $ atomically $ do
l <- readTVar v
case l of
[] -> return Nothing
(st:rest) -> do
writeTVar v rest
return (Just st)
maybe (startExternal external) return ms
dealloc st = liftIO $ atomically $ modifyTVar' v (st:)
{- Starts an external remote process running, and checks VERSION. -}
startExternal :: External -> Annex ExternalState
startExternal external = do
errrelayer <- mkStderrRelayer
st <- start errrelayer =<< Annex.gitRepo
receiveMessage st external
(const Nothing)
(checkVersion st external)
(const Nothing)
return st
where
start errrelayer g = liftIO $ do
cmdpath <- searchPath basecmd
(cmd, ps) <- maybe (pure (basecmd, [])) findShellCommand cmdpath
let basep = (proc cmd (toCommand ps))
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = CreatePipe
}
p <- propgit g basep
(Just hin, Just hout, Just herr, ph) <-
createProcess p `catchIO` runerr cmdpath
stderrelay <- async $ errrelayer herr
cv <- newTVarIO $ externalDefaultConfig external
pv <- newTVarIO Unprepared
pid <- atomically $ do
n <- succ <$> readTVar (externalLastPid external)
writeTVar (externalLastPid external) n
return n
return $ ExternalState
{ externalSend = hin
, externalReceive = hout
, externalPid = pid
, externalShutdown = do
cancel stderrelay
void $ waitForProcess ph
, externalPrepared = pv
, externalConfig = cv
}
basecmd = externalRemoteProgram $ externalType external
propgit g p = do
environ <- propGitEnv g
return $ p { env = Just environ }
runerr (Just cmd) _ =
giveup $ "Cannot run " ++ cmd ++ " -- Make sure it's executable and that its dependencies are installed."
runerr Nothing _ = do
path <- intercalate ":" <$> getSearchPath
giveup $ "Cannot run " ++ basecmd ++ " -- It is not installed in PATH (" ++ path ++ ")"
stopExternal :: External -> Annex ()
stopExternal external = liftIO $ do
l <- atomically $ swapTVar (externalState external) []
mapM_ stop l
where
stop st = do
hClose $ externalSend st
hClose $ externalReceive st
externalShutdown st
externalRemoteProgram :: ExternalType -> String
externalRemoteProgram externaltype = "git-annex-remote-" ++ externaltype
checkVersion :: ExternalState -> External -> RemoteRequest -> Maybe (Annex ())
checkVersion st external (VERSION v) = Just $
if v `elem` supportedProtocolVersions
then noop
else sendMessage st external (ERROR "unsupported VERSION")
checkVersion _ _ _ = Nothing
{- If repo has not been prepared, sends PREPARE.
-
- If the repo fails to prepare, or failed before, throws an exception with
- the error message. -}
checkPrepared :: ExternalState -> External -> Annex ()
checkPrepared st external = do
v <- liftIO $ atomically $ readTVar $ externalPrepared st
case v of
Prepared -> noop
FailedPrepare errmsg -> giveup errmsg
Unprepared ->
handleRequest' st external PREPARE Nothing $ \resp ->
case resp of
PREPARE_SUCCESS -> Just $
setprepared Prepared
PREPARE_FAILURE errmsg -> Just $ do
setprepared $ FailedPrepare errmsg
giveup errmsg
_ -> Nothing
where
setprepared status = liftIO $ atomically $ void $
swapTVar (externalPrepared st) status
{- 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 = catchNonAsync (go =<< remoteCost' gc) (const defcst)
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 defcst
_ -> Nothing
setRemoteCost r c
return c
defcst = return expensiveRemoteCost
{- Caches the availability in the git config to avoid needing to start up an
- external special remote every time time just to ask it what its
- availability is.
-
- Most remotes do not bother to implement a reply to this request;
- globally available is the default.
-}
getAvailability :: External -> Git.Repo -> RemoteGitConfig -> Annex Availability
getAvailability external r gc =
maybe (catchNonAsync query (const defavail)) return (remoteAnnexAvailability gc)
where
query = do
avail <- handleRequest external GETAVAILABILITY Nothing $ \req -> case req of
AVAILABILITY avail -> Just $ return avail
UNSUPPORTED_REQUEST -> Just defavail
_ -> Nothing
setRemoteAvailability r avail
return avail
defavail = return GloballyAvailable
claimurl :: External -> URLString -> Annex Bool
claimurl external url =
handleRequest external (CLAIMURL url) Nothing $ \req -> case req of
CLAIMURL_SUCCESS -> Just $ return True
CLAIMURL_FAILURE -> Just $ return False
UNSUPPORTED_REQUEST -> Just $ return False
_ -> Nothing
checkurl :: External -> URLString -> Annex UrlContents
checkurl external url =
handleRequest external (CHECKURL url) Nothing $ \req -> case req of
CHECKURL_CONTENTS sz f -> Just $ return $ UrlContents sz
(if null f then Nothing else Just $ mkSafeFilePath f)
-- Treat a single item multi response specially to
-- simplify the external remote implementation.
CHECKURL_MULTI ((_, sz, f):[]) ->
Just $ return $ UrlContents sz $ Just $ mkSafeFilePath f
CHECKURL_MULTI l -> Just $ return $ UrlMulti $ map mkmulti l
CHECKURL_FAILURE errmsg -> Just $ giveup errmsg
UNSUPPORTED_REQUEST -> giveup "CHECKURL not implemented by external special remote"
_ -> Nothing
where
mkmulti (u, s, f) = (u, s, mkSafeFilePath f)
retrieveUrl :: Retriever
retrieveUrl = fileRetriever $ \f k p -> do
us <- getWebUrls k
unlessM (downloadUrl k p us f) $
giveup "failed to download content"
checkKeyUrl :: Git.Repo -> CheckPresent
checkKeyUrl r k = do
showChecking r
us <- getWebUrls k
anyM (\u -> withUrlOptions $ checkBoth u (keySize k)) us
getWebUrls :: Key -> Annex [URLString]
getWebUrls key = filter supported <$> getUrls key
where
supported u = snd (getDownloader u) == WebDownloader