0bd8b17b59
This will allow distributed migration: Start a migration in one clone of a repo, and then update other clones. commitMigration is a bit of a bear.. There is some inversion of control that needs some TMVars. Also streamLogFile's finalizer does not handle recording the trees, so an interrupt at just the wrong time can cause migration.log to be emptied but the git-annex branch not updated. Sponsored-by: Graham Spencer on Patreon
133 lines
4.2 KiB
Haskell
133 lines
4.2 KiB
Haskell
{- git-annex command
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-
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- Copyright 2011-2023 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Command.Migrate where
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import Command
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import Backend
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import Types.Backend (canUpgradeKey, fastMigrate)
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import Types.KeySource
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import Annex.Content
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import qualified Command.ReKey
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import qualified Command.Fsck
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import qualified Annex
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import Logs.Migrate
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import Logs.MetaData
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import Logs.Web
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import Utility.Metered
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cmd :: Command
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cmd = withAnnexOptions [backendOption, annexedMatchingOptions, jsonOptions] $
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command "migrate" SectionUtility
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"switch data to different backend"
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paramPaths (seek <$$> optParser)
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data MigrateOptions = MigrateOptions
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{ migrateThese :: CmdParams
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, removeSize :: Bool
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}
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optParser :: CmdParamsDesc -> Parser MigrateOptions
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optParser desc = MigrateOptions
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<$> cmdParams desc
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<*> switch
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( long "remove-size"
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<> help "remove size field from keys"
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)
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seek :: MigrateOptions -> CommandSeek
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seek o = do
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withFilesInGitAnnex ww seeker =<< workTreeItems ww (migrateThese o)
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commitMigration
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where
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ww = WarnUnmatchLsFiles "migrate"
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seeker = AnnexedFileSeeker
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{ startAction = start o
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, checkContentPresent = Nothing
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, usesLocationLog = False
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}
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start :: MigrateOptions -> Maybe KeySha -> SeekInput -> RawFilePath -> Key -> CommandStart
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start o ksha si file key = do
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forced <- Annex.getRead Annex.force
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v <- Backend.getBackend (fromRawFilePath file) key
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case v of
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Nothing -> stop
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Just oldbackend -> do
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exists <- inAnnex key
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newbackend <- chooseBackend file
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if (newbackend /= oldbackend || upgradableKey oldbackend key || forced) && exists
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then go False oldbackend newbackend
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else if removeSize o && exists
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then go True oldbackend oldbackend
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else stop
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where
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go onlyremovesize oldbackend newbackend = do
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keyrec <- case ksha of
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Just (KeySha s) -> pure (MigrationRecord s)
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Nothing -> error "internal"
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starting "migrate" (mkActionItem (key, file)) si $
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perform onlyremovesize o file key keyrec oldbackend newbackend
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{- Checks if a key is upgradable to a newer representation.
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-
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- Reasons for migration:
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- - Ideally, all keys have file size metadata. Old keys may not.
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- - Something has changed in the backend, such as a bug fix.
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-}
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upgradableKey :: Backend -> Key -> Bool
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upgradableKey backend key = isNothing (fromKey keySize key) || backendupgradable
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where
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backendupgradable = maybe False (\a -> a key) (canUpgradeKey backend)
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{- Store the old backend's key in the new backend
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- The old backend's key is not dropped from it, because there may
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- be other files still pointing at that key.
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-
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- To ensure that the data we have for the old key is valid, it's
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- fscked here. First we generate the new key. This ensures that the
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- data cannot get corrupted after the fsck but before the new key is
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- generated.
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-}
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perform :: Bool -> MigrateOptions -> RawFilePath -> Key -> MigrationRecord -> Backend -> Backend -> CommandPerform
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perform onlyremovesize o file oldkey oldkeyrec oldbackend newbackend = go =<< genkey (fastMigrate oldbackend)
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where
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go Nothing = stop
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go (Just (newkey, knowngoodcontent))
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| knowngoodcontent = finish (removesize newkey)
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| otherwise = stopUnless checkcontent $
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finish (removesize newkey)
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checkcontent = Command.Fsck.checkBackend oldbackend oldkey KeyPresent afile
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finish newkey = ifM (Command.ReKey.linkKey file oldkey newkey)
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( do
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_ <- copyMetaData oldkey newkey
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-- If the old key had some associated urls, record them for
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-- the new key as well.
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urls <- getUrls oldkey
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forM_ urls $ \url ->
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setUrlPresent newkey url
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next $ Command.ReKey.cleanup file newkey $
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logMigration oldkeyrec
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, giveup "failed creating link from old to new key"
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)
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genkey _ | onlyremovesize = return $ Just (oldkey, False)
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genkey Nothing = do
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content <- calcRepo $ gitAnnexLocation oldkey
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let source = KeySource
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{ keyFilename = file
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, contentLocation = content
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, inodeCache = Nothing
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}
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newkey <- fst <$> genKey source nullMeterUpdate newbackend
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return $ Just (newkey, False)
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genkey (Just fm) = fm oldkey newbackend afile >>= \case
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Just newkey -> return (Just (newkey, True))
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Nothing -> genkey Nothing
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removesize k
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| removeSize o = alterKey k $ \kd -> kd { keySize = Nothing }
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| otherwise = k
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afile = AssociatedFile (Just file)
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