git-annex/Assistant/XMPP/Git.hs
Joey Hess 957e742dfc full-on git-annex assistant syncing now works over XMPP!
I decided to use the fallback push mode from the beginning for XMPP, since
while it uses some ugly branches, it avoids the possibility of a normal
push failing, and needing to pull and re-push. Due to the overhead of XMPP,
and the difficulty of building such a chain of actions due to the async
implementation, this seemed reasonable.

It seems to work great!
2012-11-10 14:38:50 -04:00

266 lines
7.7 KiB
Haskell

{- git over XMPP
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.XMPP.Git where
import Assistant.Common
import Assistant.NetMessager
import Assistant.Types.NetMessager
import Assistant.XMPP
import Assistant.XMPP.Buddies
import Assistant.DaemonStatus
import Assistant.Alert
import Assistant.MakeRemote
import Assistant.Sync
import qualified Command.Sync
import qualified Annex.Branch
import Annex.UUID
import Config
import Git
import qualified Git.Branch
import Locations.UserConfig
import qualified Types.Remote as Remote
import Utility.FileMode
import Network.Protocol.XMPP
import qualified Data.Text as T
import System.Posix.Env
import System.Posix.Types
import System.Process (std_in, std_out, std_err)
import Control.Concurrent
import qualified Data.ByteString as B
import qualified Data.Map as M
finishXMPPPairing :: JID -> UUID -> Assistant ()
finishXMPPPairing jid u = void $ alertWhile alert $
makeXMPPGitRemote buddy (baseJID jid) u
where
buddy = T.unpack $ buddyName jid
alert = pairRequestAcknowledgedAlert buddy Nothing
gitXMPPLocation :: JID -> String
gitXMPPLocation jid = "xmpp::" ++ T.unpack (formatJID $ baseJID jid)
makeXMPPGitRemote :: String -> JID -> UUID -> Assistant Bool
makeXMPPGitRemote buddyname jid u = do
remote <- liftAnnex $ addRemote $
makeGitRemote buddyname $ gitXMPPLocation jid
liftAnnex $ storeUUID (remoteConfig (Remote.repo remote) "uuid") u
syncNewRemote remote
return True
{- Pushes over XMPP, communicating with a specific client.
- Runs an arbitrary IO action to push, which should run git-push with
- an xmpp:: url.
-
- To handle xmpp:: urls, git push will run git-remote-xmpp, which is
- injected into its PATH, and in turn runs git-annex xmppgit. The
- dataflow them becomes:
-
- git push <--> git-annex xmppgit <--> xmppPush <-------> xmpp
- |
- git receive-pack <--> xmppReceivePack <---------------> xmpp
-
- The pipe between git-annex xmppgit and us is set up and communicated
- using two environment variables, relayIn and relayOut, that are set
- to the file descriptors to use. Another, relayControl, is used to
- propigate the exit status of git receive-pack.
-
- We listen at the other end of the pipe and relay to and from XMPP.
-}
xmppPush :: ClientID -> (Git.Repo -> IO Bool) -> Assistant Bool
xmppPush cid gitpush = runPush (SendPushRunning cid) handleDeferred $ do
sendNetMessage $ Pushing cid StartingPush
(Fd inf, writepush) <- liftIO createPipe
(readpush, Fd outf) <- liftIO createPipe
(Fd controlf, writecontrol) <- liftIO createPipe
tmp <- liftAnnex $ fromRepo gitAnnexTmpDir
let tmpdir = tmp </> "xmppgit"
installwrapper tmpdir
env <- liftIO getEnvironment
path <- liftIO getSearchPath
let myenv = M.fromList
[ ("PATH", join [searchPathSeparator] $ tmpdir:path)
, (relayIn, show inf)
, (relayOut, show outf)
, (relayControl, show controlf)
]
`M.union` M.fromList env
inh <- liftIO $ fdToHandle readpush
outh <- liftIO $ fdToHandle writepush
controlh <- liftIO $ fdToHandle writecontrol
t1 <- forkIO <~> toxmpp inh
t2 <- forkIO <~> fromxmpp outh controlh
{- This can take a long time to run, so avoid running it in the
- Annex monad. Also, override environment. -}
g <- liftAnnex gitRepo
r <- liftIO $ gitpush $ g { gitEnv = Just $ M.toList myenv }
liftIO $ do
mapM_ killThread [t1, t2]
mapM_ hClose [inh, outh, controlh]
return r
where
toxmpp inh = forever $ do
b <- liftIO $ B.hGetSome inh chunkSize
if B.null b
then liftIO $ killThread =<< myThreadId
else sendNetMessage $ Pushing cid $ SendPackOutput b
fromxmpp outh controlh = forever $ do
m <- waitNetPushMessage
case m of
(Pushing _ (ReceivePackOutput b)) ->
liftIO $ writeChunk outh b
(Pushing _ (ReceivePackDone exitcode)) ->
liftIO $ do
hPrint controlh exitcode
hFlush controlh
_ -> noop
installwrapper tmpdir = liftIO $ do
createDirectoryIfMissing True tmpdir
let wrapper = tmpdir </> "git-remote-xmpp"
program <- readProgramFile
writeFile wrapper $ unlines
[ "#!/bin/sh"
, "exec " ++ program ++ " xmppgit"
]
modifyFileMode wrapper $ addModes executeModes
type EnvVar = String
envVar :: String -> EnvVar
envVar s = "GIT_ANNEX_XMPPGIT_" ++ s
relayIn :: EnvVar
relayIn = envVar "IN"
relayOut :: EnvVar
relayOut = envVar "OUT"
relayControl :: EnvVar
relayControl = envVar "CONTROL"
relayHandle :: EnvVar -> IO Handle
relayHandle var = do
v <- getEnv var
case readish =<< v of
Nothing -> error $ var ++ " not set"
Just n -> fdToHandle $ Fd n
{- Called by git-annex xmppgit.
-
- git-push is talking to us on stdin
- we're talking to git-push on stdout
- git-receive-pack is talking to us on relayIn (via XMPP)
- we're talking to git-receive-pack on relayOut (via XMPP)
- git-receive-pack's exit code will be passed to us on relayControl
-}
xmppGitRelay :: IO ()
xmppGitRelay = do
flip relay stdout =<< relayHandle relayIn
relay stdin =<< relayHandle relayOut
code <- hGetLine =<< relayHandle relayControl
exitWith $ fromMaybe (ExitFailure 1) $ readish code
where
{- Is it possible to set up pipes and not need to copy the data
- ourselves? See splice(2) -}
relay fromh toh = void $ forkIO $ forever $ do
b <- B.hGetSome fromh chunkSize
when (B.null b) $ do
hClose fromh
hClose toh
killThread =<< myThreadId
writeChunk toh b
{- Relays git receive-pack stdin and stdout via XMPP, as well as propigating
- its exit status to XMPP. -}
xmppReceivePack :: ClientID -> Assistant Bool
xmppReceivePack cid = runPush (ReceivePushRunning cid) handleDeferred $ do
repodir <- liftAnnex $ fromRepo repoPath
let p = (proc "git" ["receive-pack", repodir])
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = Inherit
}
(Just inh, Just outh, _, pid) <- liftIO $ createProcess p
readertid <- forkIO <~> relayfromxmpp inh
relaytoxmpp outh
code <- liftIO $ waitForProcess pid
void $ sendNetMessage $ Pushing cid $ ReceivePackDone code
liftIO $ do
killThread readertid
hClose inh
hClose outh
return $ code == ExitSuccess
where
relaytoxmpp outh = do
b <- liftIO $ B.hGetSome outh chunkSize
-- empty is EOF, so exit
unless (B.null b) $ do
sendNetMessage $ Pushing cid $ ReceivePackOutput b
relaytoxmpp outh
relayfromxmpp inh = forever $ do
m <- waitNetPushMessage
case m of
(Pushing _ (SendPackOutput b)) ->
liftIO $ writeChunk inh b
_ -> noop
xmppRemotes :: ClientID -> Assistant [Remote]
xmppRemotes cid = case baseJID <$> parseJID cid of
Nothing -> return []
Just jid -> do
let loc = gitXMPPLocation jid
filter (matching loc . Remote.repo) . syncRemotes
<$> getDaemonStatus
where
matching loc r = repoIsUrl r && repoLocation r == loc
whenXMPPRemote :: ClientID -> Assistant () -> Assistant ()
whenXMPPRemote cid = unlessM (null <$> xmppRemotes cid)
handlePushMessage :: NetMessage -> Assistant ()
handlePushMessage (Pushing cid CanPush) =
whenXMPPRemote cid $
sendNetMessage $ Pushing cid PushRequest
handlePushMessage (Pushing cid PushRequest) =
go =<< liftAnnex (inRepo Git.Branch.current)
where
go Nothing = noop
go (Just branch) = do
rs <- xmppRemotes cid
liftAnnex $ Annex.Branch.commit "update"
(g, u) <- liftAnnex $ (,)
<$> gitRepo
<*> getUUID
liftIO $ Command.Sync.updateBranch (Command.Sync.syncBranch branch) g
debug ["pushing to", show rs]
forM_ rs $ \r -> xmppPush cid $ pushFallback u branch r
handlePushMessage (Pushing cid StartingPush) =
whenXMPPRemote cid $
void $ xmppReceivePack cid
handlePushMessage _ = noop
handleDeferred :: NetMessage -> Assistant ()
handleDeferred = handlePushMessage
chunkSize :: Int
chunkSize = 4096
writeChunk :: Handle -> B.ByteString -> IO ()
writeChunk h b = do
B.hPut h b
hFlush h