git-annex/Remote/Bup.hs
Joey Hess 02630b39ee
add Remote.readonly
Does nothing yet.

Considered making bup readonly, but while the content can't be removed,
it is able to delete a branch, so didn't.

This commit was supported by the NSF-funded DataLad project.
2018-08-30 11:12:18 -04:00

286 lines
8.9 KiB
Haskell

{- Using bup as a remote.
-
- Copyright 2011-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Bup (remote) where
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as L
import Data.ByteString.Lazy.UTF8 (fromString)
import Annex.Common
import qualified Annex
import Types.Remote
import Types.Creds
import qualified Git
import qualified Git.Command
import qualified Git.Config
import qualified Git.Construct
import qualified Git.Ref
import Config
import Config.Cost
import qualified Remote.Helper.Ssh as Ssh
import Remote.Helper.Special
import Remote.Helper.Messages
import Remote.Helper.Export
import Utility.Hash
import Utility.UserInfo
import Annex.UUID
import Annex.Ssh
import Utility.Metered
type BupRepo = String
remote :: RemoteType
remote = RemoteType
{ typename = "bup"
, enumerate = const (findSpecialRemotes "buprepo")
, generate = gen
, setup = bupSetup
, exportSupported = exportUnsupported
}
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
gen r u c gc = do
bupr <- liftIO $ bup2GitRemote buprepo
cst <- remoteCost gc $
if bupLocal buprepo
then nearlyCheapRemoteCost
else expensiveRemoteCost
(u', bupr') <- getBupUUID bupr u
let this = Remote
{ uuid = u'
, cost = cst
, name = Git.repoDescribe r
, storeKey = storeKeyDummy
, retrieveKeyFile = retreiveKeyFileDummy
, retrieveKeyFileCheap = retrieveCheap buprepo
-- Bup uses git, which cryptographically verifies content
-- (with SHA1, but sufficiently for this).
, retrievalSecurityPolicy = RetrievalAllKeysSecure
, removeKey = removeKeyDummy
, lockContent = Nothing
, checkPresent = checkPresentDummy
, checkPresentCheap = bupLocal buprepo
, exportActions = exportUnsupported
, whereisKey = Nothing
, remoteFsck = Nothing
, repairRepo = Nothing
, config = c
, getRepo = return r
, gitconfig = gc
, localpath = if bupLocal buprepo && not (null buprepo)
then Just buprepo
else Nothing
, remotetype = remote
, availability = if bupLocal buprepo then LocallyAvailable else GloballyAvailable
, readonly = False
, appendonly = True
, mkUnavailable = return Nothing
, getInfo = return [("repo", buprepo)]
, claimUrl = Nothing
, checkUrl = Nothing
}
return $ Just $ specialRemote' specialcfg c
(simplyPrepare $ store this buprepo)
(simplyPrepare $ retrieve buprepo)
(simplyPrepare $ remove buprepo)
(simplyPrepare $ checkKey r bupr')
this
where
buprepo = fromMaybe (giveup "missing buprepo") $ remoteAnnexBupRepo gc
specialcfg = (specialRemoteCfg c)
-- chunking would not improve bup
{ chunkConfig = NoChunks
}
bupSetup :: SetupStage -> Maybe UUID -> Maybe CredPair -> RemoteConfig -> RemoteGitConfig -> Annex (RemoteConfig, UUID)
bupSetup _ mu _ c gc = do
u <- maybe (liftIO genUUID) return mu
-- verify configuration is sane
let buprepo = fromMaybe (giveup "Specify buprepo=") $
M.lookup "buprepo" c
(c', _encsetup) <- encryptionSetup c gc
-- bup init will create the repository.
-- (If the repository already exists, bup init again appears safe.)
showAction "bup init"
unlessM (bup "init" buprepo []) $ giveup "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', u)
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
bupSplitParams :: Remote -> BupRepo -> Key -> [CommandParam] -> [CommandParam]
bupSplitParams r buprepo k src =
let os = map Param $ remoteAnnexBupSplitOptions $ gitconfig r
in bupParams "split" buprepo
(os ++ [Param "-q", Param "-n", Param (bupRef k)] ++ src)
store :: Remote -> BupRepo -> Storer
store r buprepo = byteStorer $ \k b p -> do
let params = bupSplitParams r buprepo k []
showOutput -- make way for bup output
let cmd = proc "bup" (toCommand params)
quiet <- commandProgressDisabled
let feeder = \h -> do
meteredWrite p h b
return True
liftIO $ if quiet
then feedWithQuietOutput createProcessSuccess cmd feeder
else withHandle StdinHandle createProcessSuccess cmd feeder
retrieve :: BupRepo -> Retriever
retrieve buprepo = byteRetriever $ \k sink -> do
let params = bupParams "join" buprepo [Param $ bupRef k]
let p = proc "bup" (toCommand params)
(_, Just h, _, pid) <- liftIO $ createProcess $ p { std_out = CreatePipe }
liftIO (hClose h >> forceSuccessProcess p pid)
`after` (sink =<< liftIO (L.hGetContents h))
retrieveCheap :: BupRepo -> Key -> AssociatedFile -> FilePath -> Annex Bool
retrieveCheap _ _ _ _ = return False
{- Cannot revert having stored a key in bup, but at least the data for the
- key will be used for deltaing data of other keys stored later.
-
- We can, however, remove the git branch that bup created for the key.
-}
remove :: BupRepo -> Remover
remove buprepo k = do
go =<< liftIO (bup2GitRemote buprepo)
warning "content cannot be completely removed from bup remote"
return True
where
go r
| Git.repoIsUrl r = void $ onBupRemote r boolSystem "git" params
| otherwise = void $ liftIO $ catchMaybeIO $ do
r' <- Git.Config.read r
boolSystem "git" $ Git.Command.gitCommandLine params r'
params = [ Param "branch", Param "-q", Param "-D", Param (bupRef k) ]
{- 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).
-}
checkKey :: Git.Repo -> Git.Repo -> CheckPresent
checkKey r bupr k
| Git.repoIsUrl bupr = do
showChecking r
onBupRemote bupr boolSystem "git" params
| otherwise = liftIO $ boolSystem "git" $
Git.Command.gitCommandLine params bupr
where
params =
[ Param "show-ref"
, Param "--quiet"
, Param "--verify"
, Param $ "refs/heads/" ++ bupRef 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"
unlessM (onBupRemote r boolSystem "git"
[Param "config", Param "annex.uuid", Param v]) $
giveup "ssh failed"
else liftIO $ do
r' <- Git.Config.read r
let olduuid = Git.Config.get "annex.uuid" "" r'
when (olduuid == "") $
Git.Command.run
[ Param "config"
, Param "annex.uuid"
, Param v
] r'
where
v = fromUUID u
onBupRemote :: Git.Repo -> (FilePath -> [CommandParam] -> IO a) -> FilePath -> [CommandParam] -> Annex a
onBupRemote r runner command params = do
c <- Annex.getRemoteGitConfig r
let remotecmd = "cd " ++ dir ++ " && " ++ unwords (command : toCommand params)
(sshcmd, sshparams) <- Ssh.toRepo NoConsumeStdin r c remotecmd
liftIO $ runner sshcmd sshparams
where
path = Git.repoPath r
base = fromMaybe path (stripPrefix "/~/" path)
dir = shellEscape base
{- 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 <- tryIO $ 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 giveup "please specify an absolute path"
| otherwise = Git.Construct.fromUrl $ "ssh://" ++ host ++ slash dir
where
bits = splitc ':' r
host = Prelude.head bits
dir = intercalate ":" $ 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
{- Converts a key into a git ref name, which bup-split -n will use to point
- to it. -}
bupRef :: Key -> String
bupRef k
| Git.Ref.legal True shown = shown
| otherwise = "git-annex-" ++ show (sha2_256 (fromString shown))
where
shown = key2file k
bupLocal :: BupRepo -> Bool
bupLocal = notElem ':'