git-annex/Assistant/XMPP/Git.hs
2013-07-08 12:53:08 -04:00

382 lines
12 KiB
Haskell

{- git over XMPP
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
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 Logs.UUID
import Annex.TaggedPush
import Annex.CatFile
import Config
import Git
import qualified Git.Branch
import Config.Files
import qualified Types.Remote as Remote
import qualified Remote as Remote
import Remote.List
import Utility.FileMode
import Utility.Shell
import Utility.Env
import Network.Protocol.XMPP
import qualified Data.Text as T
import System.Posix.Types
import System.Process (std_in, std_out, std_err)
import Control.Concurrent
import System.Timeout
import qualified Data.ByteString as B
import qualified Data.Map as M
{- Largest chunk of data to send in a single XMPP message. -}
chunkSize :: Int
chunkSize = 4096
{- How long to wait for an expected message before assuming the other side
- has gone away and canceling a push.
-
- This needs to be long enough to allow a message of up to 2+ times
- chunkSize to propigate up to a XMPP server, perhaps across to another
- server, and back down to us. On the other hand, other XMPP pushes can be
- delayed for running until the timeout is reached, so it should not be
- excessive.
-}
xmppTimeout :: Int
xmppTimeout = 120000000 -- 120 seconds
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
liftAnnex $ void remoteListRefresh
remote' <- liftAnnex $ fromMaybe (error "failed to add remote")
<$> Remote.byName (Just buddyname)
syncRemote 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 = do
u <- liftAnnex getUUID
sendNetMessage $ Pushing cid (StartingPush u)
(Fd inf, writepush) <- liftIO createPipe
(readpush, Fd outf) <- liftIO createPipe
(Fd controlf, writecontrol) <- liftIO createPipe
tmpdir <- gettmpdir
installwrapper tmpdir
env <- liftIO getEnvironment
path <- liftIO getSearchPath
let myenv = M.fromList
[ ("PATH", intercalate [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 0 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]
mapM_ closeFd [Fd inf, Fd outf, Fd controlf]
return r
where
toxmpp seqnum inh = do
b <- liftIO $ B.hGetSome inh chunkSize
if B.null b
then liftIO $ killThread =<< myThreadId
else do
let seqnum' = succ seqnum
sendNetMessage $ Pushing cid $
SendPackOutput seqnum' b
toxmpp seqnum' inh
fromxmpp outh controlh = withPushMessagesInSequence cid SendPack handle
where
handle (Just (Pushing _ (ReceivePackOutput _ b))) =
liftIO $ writeChunk outh b
handle (Just (Pushing _ (ReceivePackDone exitcode))) =
liftIO $ do
hPrint controlh exitcode
hFlush controlh
handle (Just _) = noop
handle Nothing = do
debug ["timeout waiting for git receive-pack output via XMPP"]
-- Send a synthetic exit code to git-annex
-- xmppgit, which will exit and cause git push
-- to die.
liftIO $ do
hPrint controlh (ExitFailure 1)
hFlush controlh
killThread =<< myThreadId
installwrapper tmpdir = liftIO $ do
createDirectoryIfMissing True tmpdir
let wrapper = tmpdir </> "git-remote-xmpp"
program <- readProgramFile
writeFile wrapper $ unlines
[ shebang_local
, "exec " ++ program ++ " xmppgit"
]
modifyFileMode wrapper $ addModes executeModes
{- Use GIT_ANNEX_TMP_DIR if set, since that may be a better temp
- dir (ie, not on a crippled filesystem where we can't make
- the wrapper executable). -}
gettmpdir = do
v <- liftIO $ getEnv "GIT_ANNEX_TMP_DIR"
case v of
Nothing -> do
tmp <- liftAnnex $ fromRepo gitAnnexTmpDir
return $ tmp </> "xmppgit"
Just d -> return $ d </> "xmppgit"
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 = 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 0 outh
code <- liftIO $ waitForProcess pid
void $ sendNetMessage $ Pushing cid $ ReceivePackDone code
liftIO $ do
killThread readertid
hClose inh
hClose outh
return $ code == ExitSuccess
where
relaytoxmpp seqnum outh = do
b <- liftIO $ B.hGetSome outh chunkSize
-- empty is EOF, so exit
unless (B.null b) $ do
let seqnum' = succ seqnum
sendNetMessage $ Pushing cid $ ReceivePackOutput seqnum' b
relaytoxmpp seqnum' outh
relayfromxmpp inh = withPushMessagesInSequence cid ReceivePack handle
where
handle (Just (Pushing _ (SendPackOutput _ b))) =
liftIO $ writeChunk inh b
handle (Just _) = noop
handle Nothing = do
debug ["timeout waiting for git send-pack output via XMPP"]
-- closing the handle will make git receive-pack exit
liftIO $ do
hClose inh
killThread =<< myThreadId
xmppRemotes :: ClientID -> UUID -> Assistant [Remote]
xmppRemotes cid theiruuid = case baseJID <$> parseJID cid of
Nothing -> return []
Just jid -> do
let loc = gitXMPPLocation jid
um <- liftAnnex uuidMap
filter (matching loc . Remote.repo) . filter (knownuuid um) . syncGitRemotes
<$> getDaemonStatus
where
matching loc r = repoIsUrl r && repoLocation r == loc
knownuuid um r = Remote.uuid r == theiruuid || M.member theiruuid um
{- Returns the ClientID that it pushed to. -}
runPush :: (Remote -> Assistant ()) -> NetMessage -> Assistant (Maybe ClientID)
runPush checkcloudrepos (Pushing cid (PushRequest theiruuid)) =
go =<< liftAnnex (inRepo Git.Branch.current)
where
go Nothing = return Nothing
go (Just branch) = do
rs <- xmppRemotes cid theiruuid
liftAnnex $ Annex.Branch.commit "update"
(g, u) <- liftAnnex $ (,)
<$> gitRepo
<*> getUUID
liftIO $ Command.Sync.updateBranch (Command.Sync.syncBranch branch) g
selfjid <- ((T.unpack <$>) . xmppClientID) <$> getDaemonStatus
if null rs
then return Nothing
else do
forM_ rs $ \r -> do
void $ alertWhile (syncAlert [r]) $
xmppPush cid (taggedPush u selfjid branch r)
checkcloudrepos r
return $ Just cid
runPush checkcloudrepos (Pushing cid (StartingPush theiruuid)) = do
rs <- xmppRemotes cid theiruuid
if null rs
then return Nothing
else do
void $ alertWhile (syncAlert rs) $
xmppReceivePack cid
mapM_ checkcloudrepos rs
return $ Just cid
runPush _ _ = return Nothing
{- Check if any of the shas that can be pushed are ones we do not
- have.
-
- (Older clients send no shas, so when there are none, always
- request a push.)
-}
handlePushNotice :: NetMessage -> Assistant ()
handlePushNotice (Pushing cid (CanPush theiruuid shas)) =
unlessM (null <$> xmppRemotes cid theiruuid) $
if null shas
then go
else ifM (haveall shas)
( debug ["ignoring CanPush with known shas"]
, go
)
where
go = do
u <- liftAnnex getUUID
sendNetMessage $ Pushing cid (PushRequest u)
haveall l = liftAnnex $ not <$> anyM donthave l
donthave sha = isNothing <$> catObjectDetails sha
handlePushNotice _ = noop
writeChunk :: Handle -> B.ByteString -> IO ()
writeChunk h b = do
B.hPut h b
hFlush h
{- Gets NetMessages for a PushSide, ensures they are in order,
- and runs an action to handle each in turn. The action will be passed
- Nothing on timeout.
-
- Does not currently reorder messages, but does ensure that any
- duplicate messages, or messages not in the sequence, are discarded.
-}
withPushMessagesInSequence :: ClientID -> PushSide -> (Maybe NetMessage -> Assistant ()) -> Assistant ()
withPushMessagesInSequence cid side a = loop 0
where
loop seqnum = do
m <- timeout xmppTimeout <~> waitInbox cid side
let go s = a m >> loop s
let next = seqnum + 1
case extractSequence =<< m of
Just seqnum'
| seqnum' == next -> go next
| seqnum' == 0 -> go seqnum
| seqnum' == seqnum -> do
debug ["ignoring duplicate sequence number", show seqnum]
loop seqnum
| otherwise -> do
debug ["ignoring out of order sequence number", show seqnum', "expected", show next]
loop seqnum
Nothing -> go seqnum
extractSequence :: NetMessage -> Maybe Int
extractSequence (Pushing _ (ReceivePackOutput seqnum _)) = Just seqnum
extractSequence (Pushing _ (SendPackOutput seqnum _)) = Just seqnum
extractSequence _ = Nothing