git-annex/Remote/Borg.hs

300 lines
10 KiB
Haskell

{- Using borg as a remote.
-
- Copyright 2020 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Remote.Borg (remote) where
import Annex.Common
import Types.Remote
import Types.Creds
import Types.Import
import qualified Git
import qualified Git.LsTree as LsTree
import Git.Types (toTreeItemType, TreeItemType(..))
import Git.FilePath
import Config
import Config.Cost
import Annex.SpecialRemote.Config
import Remote.Helper.Special
import Remote.Helper.ExportImport
import Annex.UUID
import Types.ProposedAccepted
import Utility.Metered
import qualified Remote.Helper.ThirdPartyPopulated as ThirdPartyPopulated
import Logs.Export
import Data.Either
import Text.Read
import Control.Exception (evaluate)
import Control.DeepSeq
import qualified Data.Map as M
import qualified Data.ByteString as S
import qualified Data.ByteString.Lazy as L
import qualified System.FilePath.ByteString as P
type BorgRepo = String
type BorgArchiveName = S.ByteString
remote :: RemoteType
remote = RemoteType
{ typename = "borg"
, enumerate = const (findSpecialRemotes "borgrepo")
, generate = gen
, configParser = mkRemoteConfigParser
[ optionalStringParser borgrepoField
(FieldDesc "(required) borg repository to use")
]
, setup = borgSetup
, exportSupported = exportUnsupported
, importSupported = importIsSupported
, thirdPartyPopulated = True
}
borgrepoField :: RemoteConfigField
borgrepoField = Accepted "borgrepo"
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> RemoteStateHandle -> Annex (Maybe Remote)
gen r u rc gc rs = do
c <- parsedRemoteConfig remote rc
cst <- remoteCost gc $
if borgLocal borgrepo
then nearlyCheapRemoteCost
else expensiveRemoteCost
return $ Just $ Remote
{ uuid = u
, cost = cst
, name = Git.repoDescribe r
, storeKey = storeKeyDummy
, retrieveKeyFile = retrieveKeyFileDummy
, retrieveKeyFileCheap = Nothing
-- Borg cryptographically verifies content.
, retrievalSecurityPolicy = RetrievalAllKeysSecure
, removeKey = removeKeyDummy
, lockContent = Nothing
, checkPresent = checkPresentDummy
, checkPresentCheap = borgLocal borgrepo
, exportActions = exportUnsupported
, importActions = ImportActions
{ listImportableContents = listImportableContentsM u borgrepo
, importKey = Just ThirdPartyPopulated.importKey
, retrieveExportWithContentIdentifier = retrieveExportWithContentIdentifierM borgrepo
, checkPresentExportWithContentIdentifier = checkPresentExportWithContentIdentifierM borgrepo
-- This remote is thirdPartyPopulated, so these
-- actions will never be used.
, storeExportWithContentIdentifier = storeExportWithContentIdentifier importUnsupported
, removeExportDirectoryWhenEmpty = removeExportDirectoryWhenEmpty importUnsupported
, removeExportWithContentIdentifier = removeExportWithContentIdentifier importUnsupported
}
, whereisKey = Nothing
, remoteFsck = Nothing
, repairRepo = Nothing
, config = c
, getRepo = return r
, gitconfig = gc
, localpath = if borgLocal borgrepo && not (null borgrepo)
then Just borgrepo
else Nothing
, remotetype = remote
, availability = if borgLocal borgrepo then LocallyAvailable else GloballyAvailable
, readonly = False
, appendonly = False
, mkUnavailable = return Nothing
, getInfo = return [("repo", borgrepo)]
, claimUrl = Nothing
, checkUrl = Nothing
, remoteStateHandle = rs
}
where
borgrepo = fromMaybe (giveup "missing borgrepo") $ remoteAnnexBorgRepo gc
borgSetup :: SetupStage -> Maybe UUID -> Maybe CredPair -> RemoteConfig -> RemoteGitConfig -> Annex (RemoteConfig, UUID)
borgSetup _ mu _ c _gc = do
u <- maybe (liftIO genUUID) return mu
-- verify configuration is sane
let borgrepo = maybe (giveup "Specify borgrepo=") fromProposedAccepted $
M.lookup borgrepoField c
-- The borgrepo is stored in git config, as well as this repo's
-- persistant state, so it can vary between hosts.
gitConfigSpecialRemote u c [("borgrepo", borgrepo)]
return (c, u)
borgLocal :: BorgRepo -> Bool
borgLocal = notElem ':'
borgArchive :: BorgRepo -> BorgArchiveName -> String
borgArchive r n = r ++ "::" ++ decodeBS' n
-- XXX the tree generated by using this does not seem to get grafted into
-- the git-annex branch, so would be subject to being lost to GC.
-- Is this a general problem affecting importtree too?
listImportableContentsM :: UUID -> BorgRepo -> Annex (Maybe (ImportableContents (ContentIdentifier, ByteSize)))
listImportableContentsM u borgrepo = prompt $ do
imported <- getImported u
ls <- withborglist borgrepo "{barchive}{NUL}" $ \as ->
forM as $ \archivename ->
case M.lookup archivename imported of
Just getfast -> return $ Left (archivename, getfast)
Nothing -> Right <$>
let archive = borgArchive borgrepo archivename
in withborglist archive "{size}{NUL}{path}{NUL}" $
liftIO . evaluate . force . parsefilelist archivename
if all isLeft ls && M.null (M.difference imported (M.fromList (lefts ls)))
then return Nothing -- unchanged since last time, avoid work
else Just . mkimportablecontents <$> mapM (either snd pure) ls
where
withborglist what format a = do
let p = (proc "borg" ["list", what, "--format", format])
{ std_out = CreatePipe }
(Nothing, Just h, Nothing, pid) <- liftIO $ createProcess p
l <- liftIO $ map L.toStrict
. filter (not . L.null)
. L.split 0
<$> L.hGetContents h
let cleanup = liftIO $ do
hClose h
forceSuccessProcess p pid
a l `finally` cleanup
parsefilelist archivename (bsz:f:rest) = case readMaybe (fromRawFilePath bsz) of
Nothing -> parsefilelist archivename rest
Just sz ->
let loc = genImportLocation archivename f
-- This does a little unncessary work to parse the
-- key, which is then thrown away. But, it lets the
-- file list be shrank down to only the ones that are
-- importable keys, so avoids needing to buffer all
-- the rest of the files in memory.
in case ThirdPartyPopulated.importKey' loc sz of
Just k -> (loc, (borgContentIdentifier, sz))
: parsefilelist archivename rest
Nothing -> parsefilelist archivename rest
parsefilelist _ _ = []
-- importableHistory is not used for retrieval, so is not
-- populated with old archives. Instead, a tree of archives
-- is constructed, by genImportLocation including the archive
-- name in the ImportLocation.
mkimportablecontents l = ImportableContents
{ importableContents = concat l
, importableHistory = []
}
-- We do not need a ContentIdentifier in order to retrieve a file from
-- borg; the ImportLocation contains all that's needed. So, this is left
-- empty.
borgContentIdentifier :: ContentIdentifier
borgContentIdentifier = ContentIdentifier mempty
-- Borg does not allow / in the name of an archive, so the archive
-- name will always be the first directory in the ImportLocation.
--
-- Paths in a borg archive are always relative, not absolute, so the use of
-- </> to combine the archive name with the path will always work.
genImportLocation :: BorgArchiveName -> RawFilePath -> ImportLocation
genImportLocation archivename p =
ThirdPartyPopulated.mkThirdPartyImportLocation $
archivename P.</> p
extractImportLocation :: ImportLocation -> (BorgArchiveName, RawFilePath)
extractImportLocation loc = go $ P.splitDirectories $
ThirdPartyPopulated.fromThirdPartyImportLocation loc
where
go (archivename:rest) = (archivename, P.joinPath rest)
go _ = giveup $ "Unable to parse import location " ++ fromRawFilePath (fromImportLocation loc)
-- Since the ImportLocation starts with the archive name, a list of all
-- archive names we've already imported can be found by just listing the
-- last imported tree. And the contents of those archives can be retrieved
-- by listing the subtree recursively, which will likely be quite a lot
-- faster than running borg.
getImported :: UUID -> Annex (M.Map BorgArchiveName (Annex [(ImportLocation, (ContentIdentifier, ByteSize))]))
getImported u = M.unions <$> (mapM go . exportedTreeishes =<< getExport u)
where
go t = M.fromList . mapMaybe mk
<$> inRepo (LsTree.lsTreeStrict LsTree.LsTreeNonRecursive t)
mk ti
| toTreeItemType (LsTree.mode ti) == Just TreeSubtree = Just
( getTopFilePath (LsTree.file ti)
, getcontents
(getTopFilePath (LsTree.file ti))
(LsTree.sha ti)
)
| otherwise = Nothing
getcontents archivename t = mapMaybe (mkcontents archivename)
<$> inRepo (LsTree.lsTreeStrict LsTree.LsTreeRecursive t)
mkcontents archivename ti = do
let f = ThirdPartyPopulated.fromThirdPartyImportLocation $
mkImportLocation $ getTopFilePath $ LsTree.file ti
k <- deserializeKey' (P.takeFileName f)
return
( genImportLocation archivename f
,
( borgContentIdentifier
-- defaulting to 0 size is ok, this size
-- only gets used by
-- ThirdPartyPopulated.importKey,
-- which ignores the size when the key
-- does not have a size.
, fromMaybe 0 (fromKey keySize k)
)
)
retrieveExportWithContentIdentifierM :: BorgRepo -> ImportLocation -> ContentIdentifier -> FilePath -> Annex Key -> MeterUpdate -> Annex Key
retrieveExportWithContentIdentifierM borgrepo loc cid dest k p = error "TODO"
-- Check if the file is still there in the borg archive.
-- Does not check that the content is unchanged; we assume that
-- the content of files in borg archives does not change, which is normally
-- the case. But archives may be deleted, and files may be deleted.
checkPresentExportWithContentIdentifierM :: BorgRepo -> Key -> ImportLocation -> [ContentIdentifier] -> Annex Bool
checkPresentExportWithContentIdentifierM borgrepo k loc cids = liftIO $ do
let p = proc "borg"
[ "list"
, "--format"
, "1"
, borgArchive borgrepo archivename
, fromRawFilePath archivefile
]
-- borg list exits nonzero with an error message if an archive
-- no longer exists. But, the user can delete archives at any
-- time they want. So, hide errors, and if it exists nonzero,
-- check if the borg repository still exists, and only throw an
-- exception if not.
(Nothing, Just h, Nothing, pid) <- withNullHandle $ \nullh ->
createProcess $ p
{ std_out = CreatePipe
, std_err = UseHandle nullh
}
ok <- (== "1") <$> hGetContentsStrict h
hClose h
ifM (checkSuccessProcess pid)
( return ok
, checkrepoexists
)
where
(archivename, archivefile) = extractImportLocation loc
checkrepoexists = do
let p = proc "borg"
[ "list"
, "--format"
, "1"
, borgrepo
]
(Nothing, Nothing, Nothing, pid) <- withNullHandle $ \nullh ->
createProcess $ p
{ std_out = UseHandle nullh }
ifM (checkSuccessProcess pid)
( return False -- repo exists, content not in it
, giveup $ "Unable to access borg repository " ++ borgrepo
)