git-annex/Remote/Bup.hs
2011-12-31 04:11:58 -04:00

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{- Using bup as a remote.
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Bup (remote) where
import qualified Data.ByteString.Lazy.Char8 as L
import System.IO.Error
import qualified Data.Map as M
import System.Process
import Common.Annex
import Types.Remote
import qualified Git
import qualified Git.Command
import qualified Git.Config
import qualified Git.Construct
import Config
import Annex.Ssh
import Remote.Helper.Special
import Remote.Helper.Encryptable
import Crypto
type BupRepo = String
remote :: RemoteType
remote = RemoteType {
typename = "bup",
enumerate = findSpecialRemotes "buprepo",
generate = gen,
setup = bupSetup
}
gen :: Git.Repo -> UUID -> Maybe RemoteConfig -> Annex Remote
gen r u c = do
buprepo <- getConfig r "buprepo" (error "missing buprepo")
cst <- remoteCost r (if bupLocal buprepo then semiCheapRemoteCost else expensiveRemoteCost)
bupr <- liftIO $ bup2GitRemote buprepo
(u', bupr') <- getBupUUID bupr u
return $ encryptableRemote c
(storeEncrypted r buprepo)
(retrieveEncrypted buprepo)
Remote {
uuid = u',
cost = cst,
name = Git.repoDescribe r,
storeKey = store r buprepo,
retrieveKeyFile = retrieve buprepo,
removeKey = remove,
hasKey = checkPresent r bupr',
hasKeyCheap = bupLocal buprepo,
config = c,
repo = r,
remotetype = remote
}
bupSetup :: UUID -> RemoteConfig -> Annex RemoteConfig
bupSetup u c = do
-- verify configuration is sane
let buprepo = fromMaybe (error "Specify buprepo=") $
M.lookup "buprepo" c
c' <- encryptionSetup c
-- bup init will create the repository.
-- (If the repository already exists, bup init again appears safe.)
showAction "bup init"
bup "init" buprepo [] >>! error "bup init failed"
storeBupUUID u buprepo
-- The buprepo is stored in git config, as well as this repo's
-- persistant state, so it can vary between hosts.
gitConfigSpecialRemote u c' "buprepo" buprepo
return c'
bupParams :: String -> BupRepo -> [CommandParam] -> [CommandParam]
bupParams command buprepo params =
Param command : [Param "-r", Param buprepo] ++ params
bup :: String -> BupRepo -> [CommandParam] -> Annex Bool
bup command buprepo params = do
showOutput -- make way for bup output
liftIO $ boolSystem "bup" $ bupParams command buprepo params
pipeBup :: [CommandParam] -> Maybe Handle -> Maybe Handle -> IO Bool
pipeBup params inh outh = do
p <- runProcess "bup" (toCommand params)
Nothing Nothing inh outh Nothing
ok <- waitForProcess p
case ok of
ExitSuccess -> return True
_ -> return False
bupSplitParams :: Git.Repo -> BupRepo -> Key -> CommandParam -> Annex [CommandParam]
bupSplitParams r buprepo k src = do
o <- getConfig r "bup-split-options" ""
let os = map Param $ words o
showOutput -- make way for bup output
return $ bupParams "split" buprepo
(os ++ [Param "-n", Param (show k), src])
store :: Git.Repo -> BupRepo -> Key -> Annex Bool
store r buprepo k = do
src <- inRepo $ gitAnnexLocation k
params <- bupSplitParams r buprepo k (File src)
liftIO $ boolSystem "bup" params
storeEncrypted :: Git.Repo -> BupRepo -> (Cipher, Key) -> Key -> Annex Bool
storeEncrypted r buprepo (cipher, enck) k = do
src <- inRepo $ gitAnnexLocation k
params <- bupSplitParams r buprepo enck (Param "-")
liftIO $ catchBoolIO $
withEncryptedHandle cipher (L.readFile src) $ \h ->
pipeBup params (Just h) Nothing
retrieve :: BupRepo -> Key -> FilePath -> Annex Bool
retrieve buprepo k f = do
let params = bupParams "join" buprepo [Param $ show k]
liftIO $ catchBoolIO $ do
tofile <- openFile f WriteMode
pipeBup params Nothing (Just tofile)
retrieveEncrypted :: BupRepo -> (Cipher, Key) -> FilePath -> Annex Bool
retrieveEncrypted buprepo (cipher, enck) f = do
let params = bupParams "join" buprepo [Param $ show enck]
liftIO $ catchBoolIO $ do
(pid, h) <- hPipeFrom "bup" $ toCommand params
withDecryptedContent cipher (L.hGetContents h) $ L.writeFile f
forceSuccess pid
return True
remove :: Key -> Annex Bool
remove _ = do
warning "content cannot be removed from bup remote"
return False
{- Bup does not provide a way to tell if a given dataset is present
- in a bup repository. One way it to check if the git repository has
- a branch matching the name (as created by bup split -n).
-}
checkPresent :: Git.Repo -> Git.Repo -> Key -> Annex (Either String Bool)
checkPresent r bupr k
| Git.repoIsUrl bupr = do
showAction $ "checking " ++ Git.repoDescribe r
ok <- onBupRemote bupr boolSystem "git" params
return $ Right ok
| otherwise = liftIO $ catchMsgIO $
boolSystem "git" $ Git.Command.gitCommandLine params bupr
where
params =
[ Params "show-ref --quiet --verify"
, Param $ "refs/heads/" ++ show k]
{- Store UUID in the annex.uuid setting of the bup repository. -}
storeBupUUID :: UUID -> BupRepo -> Annex ()
storeBupUUID u buprepo = do
r <- liftIO $ bup2GitRemote buprepo
if Git.repoIsUrl r
then do
showAction "storing uuid"
onBupRemote r boolSystem "git"
[Params $ "config annex.uuid " ++ v]
>>! error "ssh failed"
else liftIO $ do
r' <- Git.Config.read r
let olduuid = Git.Config.get "annex.uuid" "" r'
when (olduuid == "") $
Git.Command.run "config"
[Param "annex.uuid", Param v] r'
where
v = fromUUID u
onBupRemote :: Git.Repo -> (FilePath -> [CommandParam] -> IO a) -> FilePath -> [CommandParam] -> Annex a
onBupRemote r a command params = do
let dir = shellEscape (Git.workTree r)
sshparams <- sshToRepo r [Param $
"cd " ++ dir ++ " && " ++ unwords (command : toCommand params)]
liftIO $ a "ssh" sshparams
{- Allow for bup repositories on removable media by checking
- local bup repositories to see if they are available, and getting their
- uuid (which may be different from the stored uuid for the bup remote).
-
- If a bup repository is not available, returns NoUUID.
- This will cause checkPresent to indicate nothing from the bup remote
- is known to be present.
-
- Also, returns a version of the repo with config read, if it is local.
-}
getBupUUID :: Git.Repo -> UUID -> Annex (UUID, Git.Repo)
getBupUUID r u
| Git.repoIsUrl r = return (u, r)
| otherwise = liftIO $ do
ret <- try $ Git.Config.read r
case ret of
Right r' -> return (toUUID $ Git.Config.get "annex.uuid" "" r', r')
Left _ -> return (NoUUID, r)
{- Converts a bup remote path spec into a Git.Repo. There are some
- differences in path representation between git and bup. -}
bup2GitRemote :: BupRepo -> IO Git.Repo
bup2GitRemote "" = do
-- bup -r "" operates on ~/.bup
h <- myHomeDir
Git.Construct.fromAbsPath $ h </> ".bup"
bup2GitRemote r
| bupLocal r =
if "/" `isPrefixOf` r
then Git.Construct.fromAbsPath r
else error "please specify an absolute path"
| otherwise = Git.Construct.fromUrl $ "ssh://" ++ host ++ slash dir
where
bits = split ":" r
host = Prelude.head bits
dir = join ":" $ drop 1 bits
-- "host:~user/dir" is not supported specially by bup;
-- "host:dir" is relative to the home directory;
-- "host:" goes in ~/.bup
slash d
| null d = "/~/.bup"
| "/" `isPrefixOf` d = d
| otherwise = "/~/" ++ d
bupLocal :: BupRepo -> Bool
bupLocal = notElem ':'