git-annex/RemoteDaemon/Transport/Ssh.hs
Joey Hess 92f775eba0
convert to withCreateProcess for async exception safety
Not yet 100% done, so far I've grepped for waitForProcess and converted
everything that uses that to start the process with withCreateProcess.

Except for some things like P2P.IO and Assistant.TransferrerPool,
and Utility.CoProcess, that manage a pool of processes. See #2
in https://git-annex.branchable.com/todo/more_extensive_retries_to_mask_transient_failures/#comment-209f8a8c38e63fb3a704e1282cb269c7
for how those will need to be dealt with.

checkSuccessProcess, ignoreFailureProcess, and forceSuccessProcess calls waitForProcess, so
callers of them will also need to be dealt with, and have not been yet.
2020-06-03 15:48:09 -04:00

108 lines
3.2 KiB
Haskell

{- git-remote-daemon, git-annex-shell over ssh transport
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module RemoteDaemon.Transport.Ssh (transport, transportUsingCmd) where
import Annex.Common
import Annex.Ssh
import RemoteDaemon.Types
import RemoteDaemon.Common
import Remote.Helper.Ssh
import qualified RemoteDaemon.Transport.Ssh.Types as SshRemote
import Utility.SimpleProtocol
import qualified Git
import Git.Command
import Annex.ChangedRefs
import Control.Concurrent.STM
import Control.Concurrent.Async
transport :: Transport
transport rr@(RemoteRepo r _) url h ichan ochan = do
v <- liftAnnex h $ git_annex_shell ConsumeStdin r "notifychanges" [] []
case v of
Nothing -> noop
Just (cmd, params) -> transportUsingCmd cmd params rr url h ichan ochan
transportUsingCmd :: FilePath -> [CommandParam] -> Transport
transportUsingCmd cmd params rr@(RemoteRepo r gc) url h@(TransportHandle (LocalRepo g) s) ichan ochan = do
-- enable ssh connection caching wherever inLocalRepo is called
g' <- liftAnnex h $ sshOptionsTo r gc g
let transporthandle = TransportHandle (LocalRepo g') s
transportUsingCmd' cmd params rr url transporthandle ichan ochan
transportUsingCmd' :: FilePath -> [CommandParam] -> Transport
transportUsingCmd' cmd params (RemoteRepo r gc) url transporthandle ichan ochan =
robustConnection 1 $ withCreateProcess p go
where
p = (proc cmd (toCommand params))
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = CreatePipe
}
go (Just toh) (Just fromh) (Just errh) pid = do
-- Run all threads until one finishes and get the status
-- of the first to finish. Cancel the rest.
status <- catchDefaultIO (Right ConnectionClosed) $
handlestderr errh
`race` handlestdout fromh
`race` handlecontrol
send (DISCONNECTED url)
hClose toh
hClose fromh
void $ waitForProcess pid
return $ either (either id id) id status
go _ _ _ _ = error "internal"
send msg = atomically $ writeTChan ochan msg
fetch = do
send (SYNCING url)
ok <- inLocalRepo transporthandle $
runBool [Param "fetch", Param $ Git.repoDescribe r]
send (DONESYNCING url ok)
handlestdout fromh = do
ml <- getProtocolLine fromh
case parseMessage =<< ml of
Just SshRemote.READY -> do
send (CONNECTED url)
handlestdout fromh
Just (SshRemote.CHANGED (ChangedRefs shas)) -> do
whenM (checkShouldFetch gc transporthandle shas) $
fetch
handlestdout fromh
-- avoid reconnect on protocol error
Nothing -> return ConnectionStopping
handlecontrol = do
msg <- atomically $ readTChan ichan
case msg of
STOP -> return ConnectionStopping
LOSTNET -> return ConnectionStopping
_ -> handlecontrol
-- Old versions of git-annex-shell that do not support
-- the notifychanges command will exit with a not very useful
-- error message. Detect that error, and avoid reconnecting.
-- Propigate all stderr.
handlestderr errh = do
s <- hGetSomeString errh 1024
hPutStr stderr s
hFlush stderr
if "git-annex-shell: git-shell failed" `isInfixOf` s
then do
send $ WARNING url $ unwords
[ "Remote", Git.repoDescribe r
, "needs its git-annex upgraded"
, "to 5.20140405 or newer"
]
return ConnectionStopping
else handlestderr errh