git-annex/Assistant.hs
Joey Hess 635c9a1549 assistant: Detect stale git lock files at startup time, and remove them.
Extends the index.lock handling to other git lock files. I surveyed
all lock files used by git, and found more than I expected. All are
handled the same in git; it leaves them open while doing the operation,
possibly writing the new file content to the lock file, and then closes
them when done.

The gc.pid file is excluded because it won't affect the normal operation
of the assistant, and waiting for a gc to finish on startup wouldn't be
good.

All threads except the webapp thread wait on the new startup sanity checker
thread to complete, so they won't try to do things with git that fail
due to stale lock files. The webapp thread mostly avoids doing that kind of
thing itself. A few configurators might fail on lock files, but only if the
user is explicitly trying to run them. The webapp needs to start
immediately when the user has opened it, even if there are stale lock
files.

Arranging for the threads to wait on the startup sanity checker was a bit
of a bear. Have to get all the NotificationHandles set up before the
startup sanity checker runs, or they won't see its signal. Perhaps
the NotificationBroadcaster is not the best interface to have used for
this. Oh well, it works.

This commit was sponsored by Michael Jakl
2013-10-05 17:04:21 -04:00

150 lines
4.4 KiB
Haskell

{- git-annex assistant daemon
-
- Copyright 2012-2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Assistant where
import qualified Annex
import Assistant.Common
import Assistant.DaemonStatus
import Assistant.NamedThread
import Assistant.Types.ThreadedMonad
import Assistant.Threads.DaemonStatus
import Assistant.Threads.Watcher
import Assistant.Threads.Committer
import Assistant.Threads.Pusher
import Assistant.Threads.Merger
import Assistant.Threads.TransferWatcher
import Assistant.Threads.Transferrer
import Assistant.Threads.SanityChecker
#ifdef WITH_CLIBS
import Assistant.Threads.MountWatcher
#endif
import Assistant.Threads.NetWatcher
import Assistant.Threads.TransferScanner
import Assistant.Threads.TransferPoller
import Assistant.Threads.ConfigMonitor
import Assistant.Threads.Glacier
#ifdef WITH_WEBAPP
import Assistant.WebApp
import Assistant.Threads.WebApp
#ifdef WITH_PAIRING
import Assistant.Threads.PairListener
#endif
#ifdef WITH_XMPP
import Assistant.Threads.XMPPClient
import Assistant.Threads.XMPPPusher
#endif
#else
#warning Building without the webapp. You probably need to install Yesod..
import Assistant.Types.UrlRenderer
#endif
import qualified Utility.Daemon
import Utility.LogFile
import Utility.ThreadScheduler
import qualified Build.SysConfig as SysConfig
import System.Log.Logger
import Network.Socket (HostName)
stopDaemon :: Annex ()
stopDaemon = liftIO . Utility.Daemon.stopDaemon =<< fromRepo gitAnnexPidFile
{- Starts the daemon. If the daemon is run in the foreground, once it's
- running, can start the browser.
-
- startbrowser is passed the url and html shim file, as well as the original
- stdout and stderr descriptors. -}
startDaemon :: Bool -> Bool -> Maybe HostName -> Maybe (Maybe Handle -> Maybe Handle -> String -> FilePath -> IO ()) -> Annex ()
startDaemon assistant foreground listenhost startbrowser = do
Annex.changeState $ \s -> s { Annex.daemon = True }
pidfile <- fromRepo gitAnnexPidFile
logfile <- fromRepo gitAnnexLogFile
logfd <- liftIO $ openLog logfile
if foreground
then do
origout <- liftIO $ catchMaybeIO $
fdToHandle =<< dup stdOutput
origerr <- liftIO $ catchMaybeIO $
fdToHandle =<< dup stdError
let undaemonize a = do
debugM desc $ "logging to " ++ logfile
Utility.Daemon.lockPidFile pidfile
Utility.LogFile.redirLog logfd
a
start undaemonize $
case startbrowser of
Nothing -> Nothing
Just a -> Just $ a origout origerr
else
start (Utility.Daemon.daemonize logfd (Just pidfile) False) Nothing
where
desc
| assistant = "assistant"
| otherwise = "watch"
start daemonize webappwaiter = withThreadState $ \st -> do
checkCanWatch
dstatus <- startDaemonStatus
logfile <- fromRepo gitAnnexLogFile
liftIO $ debugM desc $ "logging to " ++ logfile
liftIO $ daemonize $
flip runAssistant (go webappwaiter)
=<< newAssistantData st dstatus
#ifdef WITH_WEBAPP
go webappwaiter = do
d <- getAssistant id
#else
go _webappwaiter = do
#endif
notice ["starting", desc, "version", SysConfig.packageversion]
urlrenderer <- liftIO newUrlRenderer
mapM_ (startthread urlrenderer)
[ watch $ commitThread
#ifdef WITH_WEBAPP
, assist $ webAppThread d urlrenderer False listenhost Nothing webappwaiter
#ifdef WITH_PAIRING
, assist $ pairListenerThread urlrenderer
#endif
#ifdef WITH_XMPP
, assist $ xmppClientThread urlrenderer
, assist $ xmppSendPackThread urlrenderer
, assist $ xmppReceivePackThread urlrenderer
#endif
#endif
, assist $ pushThread
, assist $ pushRetryThread
, assist $ mergeThread
, assist $ transferWatcherThread
, assist $ transferPollerThread
, assist $ transfererThread
, assist $ daemonStatusThread
, assist $ sanityCheckerDailyThread
, assist $ sanityCheckerHourlyThread
#ifdef WITH_CLIBS
, assist $ mountWatcherThread
#endif
, assist $ netWatcherThread
, assist $ netWatcherFallbackThread
, assist $ transferScannerThread urlrenderer
, assist $ configMonitorThread
, assist $ glacierThread
, watch $ watchThread
-- must come last so that all threads that wait
-- on it have already started waiting
, watch $ sanityCheckerStartupThread
]
liftIO waitForTermination
watch a = (True, a)
assist a = (False, a)
startthread urlrenderer (watcher, t)
| watcher || assistant = startNamedThread urlrenderer t
| otherwise = noop