assistant unused file handling

Make sanity checker run git annex unused daily, and queue up transfers
of unused files to any remotes that will have them. The transfer retrying
code works for us here, so eg when a backup disk remote is plugged in,
any transfers to it are done. Once the unused files reach a remote,
they'll be removed locally as unwanted.

If the setup does not cause unused files to go to a remote, they'll pile
up, and the sanity checker detects this using some heuristics that are
pretty good -- 1000 unused files, or 10% of disk used by unused files,
or more disk wasted by unused files than is left free. Once it detects
this, it pops up an alert in the webapp, with a button to take action.

TODO: Webapp UI to configure this, and also the ability to launch an
immediate cleanup of all unused files.

This commit was sponsored by Simon Michael.

Assistant/Threads/SanityChecker.hs

@@ -5,6 +5,8 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE CPP #-}
+
 module Assistant.Threads.SanityChecker (
 	sanityCheckerStartupThread,
 	sanityCheckerDailyThread,
@@ -16,7 +18,10 @@ import Assistant.DaemonStatus
 import Assistant.Alert
 import Assistant.Repair
 import Assistant.Ssh
+import Assistant.TransferQueue
+import Assistant.Types.UrlRenderer
 import qualified Annex.Branch
+import qualified Git
 import qualified Git.LsFiles
 import qualified Git.Command
 import qualified Git.Config
@@ -25,12 +30,26 @@ import qualified Assistant.Threads.Watcher as Watcher
 import Utility.LogFile
 import Utility.Batch
 import Utility.NotificationBroadcaster
+import Utility.DiskFree
 import Config
 import Utility.HumanTime
+import Utility.DataUnits
 import Git.Repair
 import Git.Index
+import Logs.Unused
+import Logs.Location
+import Logs.Transfer
+import Annex.Content
+import Config.Files
+import Types.Key
+import qualified Annex
+#ifdef WITH_WEBAPP
+import Assistant.WebApp.Types
+#endif
 
 import Data.Time.Clock.POSIX
+import qualified Data.Map as M
+import qualified Data.Text as T
 
 {- This thread runs once at startup, and most other threads wait for it
  - to finish. (However, the webapp thread does not, to prevent the UI
@@ -78,8 +97,8 @@ sanityCheckerHourlyThread = namedThread "SanityCheckerHourly" $ forever $ do
 	hourlyCheck
 
 {- This thread wakes up daily to make sure the tree is in good shape. -}
-sanityCheckerDailyThread :: NamedThread
-sanityCheckerDailyThread = namedThread "SanityCheckerDaily" $ forever $ do
+sanityCheckerDailyThread :: UrlRenderer -> NamedThread
+sanityCheckerDailyThread urlrenderer = namedThread "SanityCheckerDaily" $ forever $ do
 	waitForNextCheck
 
 	debug ["starting sanity check"]
@@ -90,7 +109,8 @@ sanityCheckerDailyThread = namedThread "SanityCheckerDaily" $ forever $ do
 		modifyDaemonStatus_ $ \s -> s { sanityCheckRunning = True }
 
 		now <- liftIO getPOSIXTime -- before check started
-		r <- either showerr return =<< (tryIO . batch) <~> dailyCheck
+		r <- either showerr return 
+			=<< (tryIO . batch) <~> dailyCheck urlrenderer
 
 		modifyDaemonStatus_ $ \s -> s
 			{ sanityCheckRunning = False
@@ -119,8 +139,8 @@ waitForNextCheck = do
 {- It's important to stay out of the Annex monad as much as possible while
  - running potentially expensive parts of this check, since remaining in it
  - will block the watcher. -}
-dailyCheck :: Assistant Bool
-dailyCheck = do
+dailyCheck :: UrlRenderer -> Assistant Bool
+dailyCheck urlrenderer = do
 	g <- liftAnnex gitRepo
 	batchmaker <- liftIO getBatchCommandMaker
 
@@ -147,6 +167,22 @@ dailyCheck = do
 			, Param "--auto"
 			] g
 
+	{- Check if the unused files found last time have been dealt with. -}
+	checkOldUnused urlrenderer
+
+	{- Run git-annex unused once per day. This is run as a separate
+	 - process to stay out of the annex monad and so it can run as a
+	 - batch job. -}
+	program <- liftIO readProgramFile
+	let (program', params') = batchmaker (program, [Param "unused"])
+	void $ liftIO $ boolSystem program' params'
+	{- Invalidate unused keys cache, and queue transfers of all unused
+	 - keys. -}
+	unused <- liftAnnex unusedKeys'
+	void $ liftAnnex $ setUnusedKeys unused
+	forM_ unused $ \k ->
+		queueTransfers "unused" Later k Nothing Upload
+
 	return True
   where
 	toonew timestamp now = now < (realToFrac (timestamp + slop) :: POSIXTime)
@@ -160,7 +196,8 @@ dailyCheck = do
 		insanity $ "found unstaged symlink: " ++ file
 
 hourlyCheck :: Assistant ()
-hourlyCheck = checkLogSize 0
+hourlyCheck = do
+	checkLogSize 0
 
 {- Rotate logs until log file size is < 1 mb. -}
 checkLogSize :: Int -> Assistant ()
@@ -185,3 +222,59 @@ oneHour = 60 * 60
 oneDay :: Int
 oneDay = 24 * oneHour
 
+{- If annex.expireunused is set, find any keys that have lingered unused
+ - for the specified duration, and remove them.
+ -
+ - Otherwise, check to see if unused keys are piling up, and let the user
+ - know. This uses heuristics: 1000 unused keys, or more unused keys 
+ - than the remaining free disk space, or more than 1/10th the total
+ - disk space being unused keys all suggest a problem. -}
+checkOldUnused :: UrlRenderer -> Assistant ()
+checkOldUnused urlrenderer = go =<< annexExpireUnused <$> liftAnnex Annex.getGitConfig
+  where
+  	go (Just expireunused) = do
+		m <- liftAnnex $ readUnusedLog ""
+		now <- liftIO getPOSIXTime
+		let duration = durationToPOSIXTime expireunused
+		let oldkeys = M.keys $ M.filter (tooold now duration) m
+		forM_ oldkeys $ \k -> do
+			debug ["removing old unused key", key2file k]
+			liftAnnex $ do
+				removeAnnex k
+				logStatus k InfoMissing
+	go Nothing = maybe noop prompt
+		=<< toobig =<< liftAnnex (readUnusedLog "")
+
+	tooold now duration (_, mt) =
+		maybe False (\t -> now - t >= duration) mt
+
+	toobig m = do
+		let num = M.size m
+		let diskused = foldl' sumkeysize 0 (M.keys m)
+		df <- forpath getDiskFree
+		disksize <- forpath getDiskSize
+		return $ if moreused df diskused || tenthused disksize diskused
+			then Just $ roughSize storageUnits False diskused ++
+				" is used by old files"
+			else if num > 1000
+				then Just $ show num ++ " old files exist"
+				else Nothing
+
+	moreused Nothing _ = False
+	moreused (Just df) used = df <= used
+
+	tenthused Nothing _ = False
+	tenthused (Just disksize) used = used >= disksize `div` 10
+
+	sumkeysize s k = s + fromMaybe 0 (keySize k)
+
+	forpath a = liftAnnex $ inRepo $ liftIO . a . Git.repoPath
+
+	prompt msg = 
+#ifdef WITH_WEBAPP
+		do
+			button <- mkAlertButton True (T.pack "Fix This") urlrenderer ConfigUnusedR
+			void $ addAlert $ unusedFilesAlert [button] msg
+#else
+		debug [msg]
+#endif