Most of the time, there will be no discreprancy between programPath and readProgramFile. But, the programFile might have been written by an old version of git-annex that is still installed, while a newer one is currently running. In this case, we want to run the same one that's currently running. This is especially important for things like the GIT_SSH=git-annex used for ssh connection caching. The only code that still uses readProgramFile directly is the upgrade code, which needs to know where the standalone git-annex was installed, in order to upgrade it.
		
			
				
	
	
		
			117 lines
		
	
	
	
		
			3.3 KiB
			
		
	
	
	
		
			Haskell
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
	
		
			3.3 KiB
			
		
	
	
	
		
			Haskell
		
	
	
	
	
	
{- git-annex assistant restarting
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 -
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 - Copyright 2013 Joey Hess <id@joeyh.name>
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 -
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 - Licensed under the GNU AGPL version 3 or higher.
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 -}
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{-# LANGUAGE CPP #-}
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module Assistant.Restart where
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import Assistant.Common
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import Assistant.Threads.Watcher
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import Assistant.DaemonStatus
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import Assistant.NamedThread
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import Utility.ThreadScheduler
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import Utility.NotificationBroadcaster
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import Utility.Url
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import Utility.PID
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import qualified Git.Construct
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import qualified Git.Config
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import qualified Annex
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import qualified Git
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import Annex.Path
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import Control.Concurrent
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#ifndef mingw32_HOST_OS
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import System.Posix (signalProcess, sigTERM)
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#else
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import Utility.WinProcess
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#endif
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import Network.URI
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{- Before the assistant can be restarted, have to remove our 
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 - gitAnnexUrlFile and our gitAnnexPidFile. Pausing the watcher is also
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 - a good idea, to avoid fighting when two assistants are running in the
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 - same repo.
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 -}
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prepRestart :: Assistant ()
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prepRestart = do
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	liftIO . maybe noop (`throwTo` PauseWatcher) =<< namedThreadId watchThread
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	liftIO . nukeFile =<< liftAnnex (fromRepo gitAnnexUrlFile)
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	liftIO . nukeFile =<< liftAnnex (fromRepo gitAnnexPidFile)
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{- To finish a restart, send a global redirect to the new url
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 - to any web browsers that are displaying the webapp.
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 -
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 - Wait for browser to update before terminating this process. -}
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postRestart :: URLString -> Assistant ()
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postRestart url = do
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	modifyDaemonStatus_ $ \status -> status { globalRedirUrl = Just url }
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	liftIO . sendNotification . globalRedirNotifier =<< getDaemonStatus
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	void $ liftIO $ forkIO $ do
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		threadDelaySeconds (Seconds 120)
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		terminateSelf
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terminateSelf :: IO ()
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terminateSelf =
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#ifndef mingw32_HOST_OS
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		signalProcess sigTERM =<< getPID
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#else
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		terminatePID =<< getPID
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#endif
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runRestart :: Assistant URLString
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runRestart = liftIO . newAssistantUrl
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	=<< liftAnnex (Git.repoLocation <$> Annex.gitRepo)
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{- Starts up the assistant in the repository, and waits for it to create
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 - a gitAnnexUrlFile. Waits for the assistant to be up and listening for
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 - connections by testing the url. -}
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newAssistantUrl :: FilePath -> IO URLString
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newAssistantUrl repo = do
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	startAssistant repo
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	geturl
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  where
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	geturl = do
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		r <- Git.Config.read =<< Git.Construct.fromPath repo
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		waiturl $ gitAnnexUrlFile r
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	waiturl urlfile = do
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		v <- tryIO $ readFile urlfile
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		case v of
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			Left _ -> delayed $ waiturl urlfile
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			Right url -> ifM (assistantListening url)
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				( return url
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				, delayed $ waiturl urlfile
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				)
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	delayed a = do
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		threadDelay 100000 -- 1/10th of a second
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		a
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{- Checks if the assistant is listening on an url.
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 -
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 - Always checks http, because https with self-signed cert is problimatic.
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 - warp-tls listens to http, in order to show an error page, so this works.
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 -}
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assistantListening :: URLString -> IO Bool
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assistantListening url = catchBoolIO $ exists url' def
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  where
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	url' = case parseURI url of
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		Nothing -> url
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		Just uri -> show $ uri
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			{ uriScheme = "http:"
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			}
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{- Does not wait for assistant to be listening for web connections. 
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 -
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 - On windows, the assistant does not daemonize, which is why the forkIO is
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 - done.
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 -}
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startAssistant :: FilePath -> IO ()
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startAssistant repo = void $ forkIO $ do
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	program <- programPath
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	(_, _, _, pid) <- 
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		createProcess $
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			(proc program ["assistant"]) { cwd = Just repo }
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	void $ checkSuccessProcess pid
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