git-annex/Command/Get.hs
Joey Hess 0f921307e7 mirror: New command, makes two repositories contain the same set of files.
This is a simple approach for setting up a mirroring repository.

It will work with any type of remotes.

Mirror --from is more expensive than mirror --to in general.
OTOH, mirror --from will get the file from any remote that has it, not only
the named mirror remote. And if the named mirror remote is not the fastest
available remote with a file, that can speed things up.

It would be possible to make the assistant or watch command do a more
dynamic mirroring, that didn't need to scan every time.
2013-08-20 15:46:35 -04:00

90 lines
2.7 KiB
Haskell

{- git-annex command
-
- Copyright 2010, 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Get where
import Common.Annex
import Command
import qualified Remote
import Annex.Content
import Logs.Transfer
import Annex.Wanted
import GitAnnex.Options
import qualified Command.Move
import Types.Key
def :: [Command]
def = [withOptions getOptions $ command "get" paramPaths seek
SectionCommon "make content of annexed files available"]
getOptions :: [Option]
getOptions = fromOption : keyOptions
seek :: [CommandSeek]
seek =
[ withField fromOption Remote.byNameWithUUID $ \from ->
withKeyOptions (startKeys from) $
withFilesInGit $ whenAnnexed $ start from
]
start :: Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
start from file (key, _) = start' expensivecheck from key (Just file)
where
expensivecheck = checkAuto (numCopiesCheck file key (<) <||> wantGet False (Just file))
startKeys :: Maybe Remote -> Key -> CommandStart
startKeys from key = start' (return True) from key Nothing
start' :: Annex Bool -> Maybe Remote -> Key -> AssociatedFile -> CommandStart
start' expensivecheck from key afile = stopUnless (not <$> inAnnex key) $
stopUnless expensivecheck $
case from of
Nothing -> go $ perform key afile
Just src ->
stopUnless (Command.Move.fromOk src key) $
go $ Command.Move.fromPerform src False key afile
where
go a = do
showStart "get" (fromMaybe (key2file key) afile)
next a
perform :: Key -> AssociatedFile -> CommandPerform
perform key afile = stopUnless (getViaTmp key $ getKeyFile key afile) $
next $ return True -- no cleanup needed
{- Try to find a copy of the file in one of the remotes,
- and copy it to here. -}
getKeyFile :: Key -> AssociatedFile -> FilePath -> Annex Bool
getKeyFile key afile dest = dispatch =<< Remote.keyPossibilities key
where
dispatch [] = do
showNote "not available"
showlocs
return False
dispatch remotes = trycopy remotes remotes
trycopy full [] = do
Remote.showTriedRemotes full
showlocs
return False
trycopy full (r:rs) =
ifM (probablyPresent r)
( docopy r (trycopy full rs)
, trycopy full rs
)
showlocs = Remote.showLocations key [] $
"No other repository is known to contain the file."
-- This check is to avoid an ugly message if a remote is a
-- drive that is not mounted.
probablyPresent r
| Remote.hasKeyCheap r =
either (const False) id <$> Remote.hasKey r key
| otherwise = return True
docopy r continue = do
ok <- download (Remote.uuid r) key afile noRetry $ \p -> do
showAction $ "from " ++ Remote.name r
Remote.retrieveKeyFile r key afile dest p
if ok then return ok else continue