git-annex/Assistant/TransferSlots.hs
Joey Hess 40ecf58d4b
update licenses from GPL to AGPL
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.

Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.

(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
2019-03-13 15:48:14 -04:00

300 lines
10 KiB
Haskell

{- git-annex assistant transfer slots
-
- Copyright 2012 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Assistant.TransferSlots where
import Assistant.Common
import Utility.ThreadScheduler
import Assistant.Types.TransferSlots
import Assistant.DaemonStatus
import Assistant.TransferrerPool
import Assistant.Types.TransferrerPool
import Assistant.Types.TransferQueue
import Assistant.TransferQueue
import Assistant.Alert
import Assistant.Alert.Utility
import Assistant.Commits
import Assistant.Drop
import Types.Transfer
import Logs.Transfer
import Logs.Location
import qualified Git
import qualified Remote
import qualified Types.Remote as Remote
import Annex.Content
import Annex.Wanted
import Annex.Path
import Utility.Batch
import Types.NumCopies
import qualified Data.Map as M
import qualified Control.Exception as E
import Control.Concurrent
import qualified Control.Concurrent.MSemN as MSemN
#ifndef mingw32_HOST_OS
import System.Posix.Process (getProcessGroupIDOf)
import System.Posix.Signals (signalProcessGroup, sigTERM, sigKILL)
#else
import System.Win32.Process (terminateProcessById)
#endif
type TransferGenerator = Assistant (Maybe (Transfer, TransferInfo, Transferrer -> Assistant ()))
{- Waits until a transfer slot becomes available, then runs a
- TransferGenerator, and then runs the transfer action in its own thread.
-}
inTransferSlot :: FilePath -> BatchCommandMaker -> TransferGenerator -> Assistant ()
inTransferSlot program batchmaker gen = do
flip MSemN.wait 1 <<~ transferSlots
runTransferThread program batchmaker =<< gen
{- Runs a TransferGenerator, and its transfer action,
- without waiting for a slot to become available. -}
inImmediateTransferSlot :: FilePath -> BatchCommandMaker -> TransferGenerator -> Assistant ()
inImmediateTransferSlot program batchmaker gen = do
flip MSemN.signal (-1) <<~ transferSlots
runTransferThread program batchmaker =<< gen
{- Runs a transfer action, in an already allocated transfer slot.
- Once it finishes, frees the transfer slot.
-
- Note that the action is subject to being killed when the transfer
- is canceled or paused.
-
- A PauseTransfer exception is handled by letting the action be killed,
- then pausing the thread until a ResumeTransfer exception is raised,
- then rerunning the action.
-}
runTransferThread :: FilePath -> BatchCommandMaker -> Maybe (Transfer, TransferInfo, Transferrer -> Assistant ()) -> Assistant ()
runTransferThread _ _ Nothing = flip MSemN.signal 1 <<~ transferSlots
runTransferThread program batchmaker (Just (t, info, a)) = do
d <- getAssistant id
aio <- asIO1 a
tid <- liftIO $ forkIO $ runTransferThread' program batchmaker d aio
updateTransferInfo t $ info { transferTid = Just tid }
runTransferThread' :: FilePath -> BatchCommandMaker -> AssistantData -> (Transferrer -> IO ()) -> IO ()
runTransferThread' program batchmaker d run = go
where
go = catchPauseResume $
withTransferrer program batchmaker (transferrerPool d)
run
pause = catchPauseResume $
runEvery (Seconds 86400) noop
{- Note: This must use E.try, rather than E.catch.
- When E.catch is used, and has called go in its exception
- handler, Control.Concurrent.throwTo will block sometimes
- when signaling. Using E.try avoids the problem. -}
catchPauseResume a' = do
r <- E.try a' :: IO (Either E.SomeException ())
case r of
Left e -> case E.fromException e of
Just PauseTransfer -> pause
Just ResumeTransfer -> go
_ -> done
_ -> done
done = runAssistant d $
flip MSemN.signal 1 <<~ transferSlots
{- By the time this is called, the daemonstatus's currentTransfers map should
- already have been updated to include the transfer. -}
genTransfer :: Transfer -> TransferInfo -> TransferGenerator
genTransfer t info = case transferRemote info of
Just remote -> ifM (unpluggedremovabledrive remote)
( do
-- optimisation, since the transfer would fail
liftAnnex $ recordFailedTransfer t info
void $ removeTransfer t
return Nothing
, ifM (liftAnnex $ shouldTransfer t info)
( do
debug [ "Transferring:" , describeTransfer t info ]
notifyTransfer
return $ Just (t, info, go remote)
, do
debug [ "Skipping unnecessary transfer:",
describeTransfer t info ]
void $ removeTransfer t
finishedTransfer t (Just info)
return Nothing
)
)
_ -> return Nothing
where
direction = transferDirection t
isdownload = direction == Download
unpluggedremovabledrive remote = Git.repoIsLocalUnknown
<$> liftAnnex (Remote.getRepo remote)
{- Alerts are only shown for successful transfers.
- Transfers can temporarily fail for many reasons,
- so there's no point in bothering the user about
- those. The assistant should recover.
-
- After a successful upload, handle dropping it from
- here, if desired. In this case, the remote it was
- uploaded to is known to have it.
-
- Also, after a successful transfer, the location
- log has changed. Indicate that a commit has been
- made, in order to queue a push of the git-annex
- branch out to remotes that did not participate
- in the transfer.
-
- If the process failed, it could have crashed,
- so remove the transfer from the list of current
- transfers, just in case it didn't stop
- in a way that lets the TransferWatcher do its
- usual cleanup. However, first check if something else is
- running the transfer, to avoid removing active transfers.
-}
go remote transferrer = ifM (liftIO $ performTransfer transferrer t info)
( do
case associatedFile info of
AssociatedFile Nothing -> noop
AssociatedFile (Just af) -> void $
addAlert $ makeAlertFiller True $
transferFileAlert direction True af
unless isdownload $
handleDrops
("object uploaded to " ++ show remote)
True (transferKey t)
(associatedFile info)
[mkVerifiedCopy RecentlyVerifiedCopy remote]
void recordCommit
, whenM (liftAnnex $ isNothing <$> checkTransfer t) $
void $ removeTransfer t
)
{- Called right before a transfer begins, this is a last chance to avoid
- unnecessary transfers.
-
- For downloads, we obviously don't need to download if the already
- have the object.
-
- Smilarly, for uploads, check if the remote is known to already have
- the object.
-
- Also, uploads get queued to all remotes, in order of cost.
- This may mean, for example, that an object is uploaded over the LAN
- to a locally paired client, and once that upload is done, a more
- expensive transfer remote no longer wants the object. (Since
- all the clients have it already.) So do one last check if this is still
- preferred content.
-
- We'll also do one last preferred content check for downloads. An
- example of a case where this could be needed is if a download is queued
- for a file that gets moved out of an archive directory -- but before
- that download can happen, the file is put back in the archive.
-}
shouldTransfer :: Transfer -> TransferInfo -> Annex Bool
shouldTransfer t info
| transferDirection t == Download =
(not <$> inAnnex key) <&&> wantGet True (Just key) file
| transferDirection t == Upload = case transferRemote info of
Nothing -> return False
Just r -> notinremote r
<&&> wantSend True (Just key) file (Remote.uuid r)
| otherwise = return False
where
key = transferKey t
file = associatedFile info
{- Trust the location log to check if the remote already has
- the key. This avoids a roundtrip to the remote. -}
notinremote r = notElem (Remote.uuid r) <$> loggedLocations key
{- Queue uploads of files downloaded to us, spreading them
- out to other reachable remotes.
-
- Downloading a file may have caused a remote to not want it;
- so check for drops from remotes.
-
- Uploading a file may cause the local repo, or some other remote to not
- want it; handle that too.
-}
finishedTransfer :: Transfer -> Maybe TransferInfo -> Assistant ()
finishedTransfer t (Just info)
| transferDirection t == Download =
whenM (liftAnnex $ inAnnex $ transferKey t) $ do
dodrops False
void $ queueTransfersMatching (/= transferUUID t)
"newly received object"
Later (transferKey t) (associatedFile info) Upload
| otherwise = dodrops True
where
dodrops fromhere = handleDrops
("drop wanted after " ++ describeTransfer t info)
fromhere (transferKey t) (associatedFile info) []
finishedTransfer _ _ = noop
{- Pause a running transfer. -}
pauseTransfer :: Transfer -> Assistant ()
pauseTransfer = cancelTransfer True
{- Cancel a running transfer. -}
cancelTransfer :: Bool -> Transfer -> Assistant ()
cancelTransfer pause t = do
m <- getCurrentTransfers
unless pause $
{- remove queued transfer -}
void $ dequeueTransfers $ equivilantTransfer t
{- stop running transfer -}
maybe noop stop (M.lookup t m)
where
stop info = do
{- When there's a thread associated with the
- transfer, it's signaled first, to avoid it
- displaying any alert about the transfer having
- failed when the transfer process is killed. -}
liftIO $ maybe noop signalthread $ transferTid info
liftIO $ maybe noop killproc $ transferPid info
if pause
then void $ alterTransferInfo t $
\i -> i { transferPaused = True }
else void $ removeTransfer t
signalthread tid
| pause = throwTo tid PauseTransfer
| otherwise = killThread tid
killproc pid = void $ tryIO $ do
#ifndef mingw32_HOST_OS
{- In order to stop helper processes like rsync,
- kill the whole process group of the process
- running the transfer. -}
g <- getProcessGroupIDOf pid
let signal sig = void $ tryIO $ signalProcessGroup sig g
signal sigTERM
threadDelay 50000 -- 0.05 second grace period
signal sigKILL
#else
terminateProcessById pid
#endif
{- Start or resume a transfer. -}
startTransfer :: Transfer -> Assistant ()
startTransfer t = do
m <- getCurrentTransfers
maybe startqueued go (M.lookup t m)
where
go info = maybe (start info) resume $ transferTid info
startqueued = do
is <- map snd <$> getMatchingTransfers (== t)
maybe noop start $ headMaybe is
resume tid = do
alterTransferInfo t $ \i -> i { transferPaused = False }
liftIO $ throwTo tid ResumeTransfer
start info = do
program <- liftIO programPath
batchmaker <- liftIO getBatchCommandMaker
inImmediateTransferSlot program batchmaker $
genTransfer t info
getCurrentTransfers :: Assistant TransferMap
getCurrentTransfers = currentTransfers <$> getDaemonStatus