assistant: Smarter log file rotation, which takes free disk space into account.

Assistant/Threads/SanityChecker.hs

@@ -38,6 +38,7 @@ import Assistant.Unused
 import Logs.Unused
 import Logs.Transfer
 import Config.Files
+import Utility.DiskFree
 import qualified Annex
 #ifdef WITH_WEBAPP
 import Assistant.WebApp.Types
@@ -203,17 +204,27 @@ hourlyCheck = do
 #endif
 
 #ifndef mingw32_HOST_OS
-{- Rotate logs until log file size is < 1 mb. -}
+{- Rotate logs once when total log file size is > 2 mb.
+ -
+ - If total log size is larger than the amount of free disk space,
+ - continue rotating logs until size is < 2 mb, even if this
+ - results in immediately losing the just logged data.
+ -}
 checkLogSize :: Int -> Assistant ()
 checkLogSize n = do
 	f <- liftAnnex $ fromRepo gitAnnexLogFile
 	logs <- liftIO $ listLogs f
 	totalsize <- liftIO $ sum <$> mapM filesize logs
-	when (totalsize > oneMegabyte) $ do
+	when (totalsize > 2 * oneMegabyte) $ do
 		notice ["Rotated logs due to size:", show totalsize]
 		liftIO $ openLog f >>= redirLog
-		when (n < maxLogs + 1) $
-			checkLogSize $ n + 1
+		when (n < maxLogs + 1) $ do
+			df <- liftIO $ getDiskFree $ takeDirectory f
+			case df of
+				Just free
+					| free < fromIntegral totalsize ->
+						checkLogSize (n + 1)
+				_ -> noop
   where
 	filesize f = fromIntegral . fileSize <$> liftIO (getFileStatus f)
 

debian/changelog

@@ -30,6 +30,8 @@ git-annex (5.20140228) UNRELEASED; urgency=medium
   * webdav: When built with a new enough haskell DAV (0.6), disable
     the http response timeout, which was only 5 seconds.
   * webapp: Include no-pty in ssh authorized_keys lines.
+  * assistant: Smarter log file rotation, which takes free disk space
+    into account.
 
  -- Joey Hess <joeyh@debian.org>  Fri, 28 Feb 2014 14:52:15 -0400
 

doc/bugs/Log_rotation_loses_large_logs.mdwn

@@ -59,3 +59,11 @@ pgl@....:/....../.git/annex$ cat daemon.log.9
 
 # End of transcript or log.
 """]]
+
+> Changed log rotation to only rotate 1 log per hour max,
+> unless the total size of the log files is larger than the 
+> free disk space on the filesystem containing them.
+> 
+> This way, runaway log growth will still be contained,
+> but logs will generally rotate slowly enough to give plenty of time
+> to see what's in them. [[done]] --[[Joey]]