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|
{- git-annex assistant repo syncing
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Sync where
import Assistant.Common
import Assistant.Pushes
import Assistant.NetMessager
import Assistant.Types.NetMessager
import Assistant.Alert
import Assistant.DaemonStatus
import Assistant.ScanRemotes
import qualified Command.Sync
import Utility.Parallel
import qualified Git
import qualified Git.Branch
import qualified Git.Ref
import qualified Git.Command
import qualified Remote
import qualified Types.Remote as Remote
import qualified Annex.Branch
import Annex.UUID
import Data.Time.Clock
import qualified Data.Map as M
import Control.Concurrent
{- Syncs with remotes that may have been disconnected for a while.
-
- First gets git in sync, and then prepares any necessary file transfers.
-
- An expensive full scan is queued when the git-annex branches of some of
- the remotes have diverged from the local git-annex branch. Otherwise,
- it's sufficient to requeue failed transfers.
-}
reconnectRemotes :: Bool -> [Remote] -> Assistant ()
reconnectRemotes _ [] = noop
reconnectRemotes notifypushes rs = void $ do
alertWhile (syncAlert rs) $ do
(ok, diverged) <- sync
=<< liftAnnex (inRepo Git.Branch.current)
addScanRemotes diverged rs
return ok
where
gitremotes = filter (notspecialremote . Remote.repo) rs
notspecialremote r
| Git.repoIsUrl r = True
| Git.repoIsLocal r = True
| otherwise = False
sync (Just branch) = do
diverged <- snd <$> manualPull (Just branch) gitremotes
now <- liftIO getCurrentTime
ok <- pushToRemotes now notifypushes gitremotes
return (ok, diverged)
{- No local branch exists yet, but we can try pulling. -}
sync Nothing = do
diverged <- snd <$> manualPull Nothing gitremotes
return (True, diverged)
{- Updates the local sync branch, then pushes it to all remotes, in
- parallel, along with the git-annex branch. This is the same
- as "git annex sync", except in parallel, and will co-exist with use of
- "git annex sync".
-
- After the pushes to normal git remotes, also signals XMPP clients that
- they can request an XMPP push.
-
- Avoids running possibly long-duration commands in the Annex monad, so
- as not to block other threads.
-
- This can fail, when the remote's sync branch (or git-annex branch) has
- been updated by some other remote pushing into it, or by the remote
- itself. To handle failure, a manual pull and merge is done, and the push
- is retried.
-
- When there's a lot of activity, we may fail more than once.
- On the other hand, we may fail because the remote is not available.
- Rather than retrying indefinitely, after the first retry we enter a
- fallback mode, where our push is guarenteed to succeed if the remote is
- reachable. If the fallback fails, the push is queued to be retried
- later.
-}
pushToRemotes :: UTCTime -> Bool -> [Remote] -> Assistant Bool
pushToRemotes now notifypushes remotes = do
(g, branch, u) <- liftAnnex $ do
Annex.Branch.commit "update"
(,,)
<$> gitRepo
<*> inRepo Git.Branch.current
<*> getUUID
let (xmppremotes, normalremotes) = partition isXMPPRemote remotes
ret <- go True branch g u normalremotes
forM_ xmppremotes $ \r ->
sendNetMessage $ Pushing (getXMPPClientID r) CanPush
return ret
where
go _ Nothing _ _ _ = return True -- no branch, so nothing to do
go _ _ _ _ [] = return True -- no remotes, so nothing to do
go shouldretry (Just branch) g u rs = do
debug ["pushing to", show rs]
liftIO $ Command.Sync.updateBranch (Command.Sync.syncBranch branch) g
(succeeded, failed) <- liftIO $ inParallel (push g branch) rs
updatemap succeeded []
if null failed
then do
when notifypushes $
sendNetMessage $ NotifyPush $
map Remote.uuid succeeded
return True
else if shouldretry
then retry branch g u failed
else fallback branch g u failed
updatemap succeeded failed = changeFailedPushMap $ \m ->
M.union (makemap failed) $
M.difference m (makemap succeeded)
makemap l = M.fromList $ zip l (repeat now)
retry branch g u rs = do
debug ["trying manual pull to resolve failed pushes"]
void $ manualPull (Just branch) rs
go False (Just branch) g u rs
fallback branch g u rs = do
debug ["fallback pushing to", show rs]
(succeeded, failed) <- liftIO $
inParallel (\r -> pushFallback u branch r g) rs
updatemap succeeded failed
when (notifypushes && (not $ null succeeded)) $
sendNetMessage $ NotifyPush $
map Remote.uuid succeeded
return $ null failed
push g branch remote = Command.Sync.pushBranch remote branch g
{- This fallback push mode pushes to branches on the remote that have our
- uuid in them. While ugly, those branches are reserved for pushing by us,
- and so our pushes will never conflict with other pushes. -}
pushFallback :: UUID -> Git.Ref -> Remote -> Git.Repo -> IO Bool
pushFallback u branch remote = Git.Command.runBool "push" params
where
params =
[ Param $ Remote.name remote
, Param $ refspec Annex.Branch.name
, Param $ refspec branch
]
{- Push to refs/synced/uuid/branch; this
- avoids cluttering up the branch display. -}
refspec b = concat
[ s
, ":"
, "refs/synced/" ++ fromUUID u ++ "/" ++ s
]
where s = show $ Git.Ref.base b
{- Manually pull from remotes and merge their branches. -}
manualPull :: Maybe Git.Ref -> [Remote] -> Assistant ([Bool], Bool)
manualPull currentbranch remotes = do
g <- liftAnnex gitRepo
results <- liftIO $ forM remotes $ \r ->
Git.Command.runBool "fetch" [Param $ Remote.name r] g
haddiverged <- liftAnnex Annex.Branch.forceUpdate
forM_ remotes $ \r ->
liftAnnex $ Command.Sync.mergeRemote r currentbranch
return (results, haddiverged)
{- Start syncing a newly added remote, using a background thread. -}
syncNewRemote :: Remote -> Assistant ()
syncNewRemote remote = do
updateSyncRemotes
thread <- asIO $ do
reconnectRemotes False [remote]
void $ liftIO $ forkIO $ thread
|
