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authorGravatar Joey Hess <joey@kitenet.net>2012-08-22 14:51:11 -0400
committerGravatar Joey Hess <joey@kitenet.net>2012-08-22 15:05:57 -0400
commit5c3e14649ee7c404f86a1b82b648d896762cbbc2 (patch)
tree832bbe820a62a9fec50a5a179c114c9a8767006c /Assistant
parent5d577c32a946a070c70ddba192f3d8cf4229b7fa (diff)
avoid unnecessary transfer scans when syncing a disconnected remote
Found a very cheap way to determine when a disconnected remote has diverged, and has new content that needs to be transferred: Piggyback on the git-annex branch update, which already checks for divergence. However, this does not check if new content has appeared locally while disconnected, that should be transferred to the remote. Also, this does not handle cases where the two git repos are in sync, but their content syncing has not caught up yet. This code could have its efficiency improved: * When multiple remotes are synced, if any one has diverged, they're all queued for transfer scans. * The transfer scanner could be told whether the remote has new content, the local repo has new content, or both, and could optimise its scan accordingly.
Diffstat (limited to 'Assistant')
-rw-r--r--Assistant/DaemonStatus.hs4
-rw-r--r--Assistant/Sync.hs23
2 files changed, 18 insertions, 9 deletions
diff --git a/Assistant/DaemonStatus.hs b/Assistant/DaemonStatus.hs
index aa990df34..4a0d271a3 100644
--- a/Assistant/DaemonStatus.hs
+++ b/Assistant/DaemonStatus.hs
@@ -238,7 +238,8 @@ updateAlertMap dstatus a = notifyAlert dstatus `after` modifyDaemonStatus_ dstat
where
go s = s { alertMap = a (alertMap s) }
-{- Displays an alert while performing an activity.
+{- Displays an alert while performing an activity that returns True on
+ - success.
-
- The alert is left visible afterwards, as filler.
- Old filler is pruned, to prevent the map growing too large. -}
@@ -247,6 +248,7 @@ alertWhile dstatus alert a = alertWhile' dstatus alert $ do
r <- a
return $ (r, r)
+{- Like alertWhile, but allows the activity to return a value too. -}
alertWhile' :: DaemonStatusHandle -> Alert -> IO (Bool, a) -> IO a
alertWhile' dstatus alert a = do
let alert' = alert { alertClass = Activity }
diff --git a/Assistant/Sync.hs b/Assistant/Sync.hs
index 11d33a54f..b0f3890ee 100644
--- a/Assistant/Sync.hs
+++ b/Assistant/Sync.hs
@@ -27,21 +27,27 @@ import qualified Data.Map as M
{- Syncs with remotes that may have been disconnected for a while.
-
- After getting git in sync, queues a scan for file transfers.
+ - To avoid doing that expensive scan unnecessarily, it's only run
+ - if the git-annex branches of the remotes have diverged from the
+ - local git-annex branch.
-}
syncRemotes :: ThreadName -> ThreadState -> DaemonStatusHandle -> ScanRemoteMap -> [Remote] -> IO ()
syncRemotes _ _ _ _ [] = noop
-syncRemotes threadname st dstatus scanremotes rs = do
- void $ alertWhile dstatus (syncAlert rs) $ do
+syncRemotes threadname st dstatus scanremotes rs = void $
+ alertWhile dstatus (syncAlert rs) $ do
sync =<< runThreadState st (inRepo Git.Branch.current)
- addScanRemotes scanremotes rs
where
sync (Just branch) = do
- manualPull st (Just branch) rs
+ haddiverged <- manualPull st (Just branch) rs
+ when haddiverged $
+ addScanRemotes scanremotes rs
now <- getCurrentTime
pushToRemotes threadname now st Nothing rs
{- No local branch exists yet, but we can try pulling. -}
sync Nothing = do
- manualPull st Nothing rs
+ haddiverged <- manualPull st Nothing rs
+ when haddiverged $
+ addScanRemotes scanremotes rs
return True
{- Updates the local sync branch, then pushes it to all remotes, in
@@ -85,15 +91,16 @@ pushToRemotes threadname now st mpushmap remotes = do
retry branch g rs = do
debug threadname [ "trying manual pull to resolve failed pushes" ]
- manualPull st (Just branch) rs
+ void $ manualPull st (Just branch) rs
go False (Just branch) g rs
{- Manually pull from remotes and merge their branches. -}
-manualPull :: ThreadState -> (Maybe Git.Ref) -> [Remote] -> IO ()
+manualPull :: ThreadState -> (Maybe Git.Ref) -> [Remote] -> IO Bool
manualPull st currentbranch remotes = do
g <- runThreadState st $ fromRepo id
forM_ remotes $ \r ->
Git.Command.runBool "fetch" [Param $ Remote.name r] g
- runThreadState st $ Annex.Branch.forceUpdate
+ haddiverged <- runThreadState st $ Annex.Branch.forceUpdate
forM_ remotes $ \r ->
runThreadState st $ Command.Sync.mergeRemote r currentbranch
+ return haddiverged