git-annex/Remote/Helper/ExportImport.hs
Joey Hess 0e44c252c8
avoid getting creds from environment during autoenable
When autoenabling special remotes of type S3, weddav, or glacier, do not
take login credentials from environment variables, as the user may not be
expecting the autoenable to happen, and may have those set for other
purposes.
2021-03-17 09:41:12 -04:00

382 lines
14 KiB
Haskell

{- Helper to make remotes support export and import (or not).
-
- Copyright 2017-2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE FlexibleInstances, FlexibleContexts #-}
module Remote.Helper.ExportImport where
import Annex.Common
import Types.Remote
import Types.Key
import Types.ProposedAccepted
import Backend
import Remote.Helper.Encryptable (encryptionIsEnabled)
import qualified Database.Export as Export
import qualified Database.ContentIdentifier as ContentIdentifier
import Annex.Export
import Annex.LockFile
import Annex.SpecialRemote.Config
import Git.Types (fromRef)
import Logs.Export
import Logs.ContentIdentifier (recordContentIdentifier)
import Control.Concurrent.STM
-- | Use for remotes that do not support exports.
class HasExportUnsupported a where
exportUnsupported :: a
instance HasExportUnsupported (ParsedRemoteConfig -> RemoteGitConfig -> Annex Bool) where
exportUnsupported = \_ _ -> return False
instance HasExportUnsupported (ExportActions Annex) where
exportUnsupported = ExportActions
{ storeExport = nope
, retrieveExport = nope
, checkPresentExport = \_ _ -> return False
, removeExport = nope
, versionedExport = False
, removeExportDirectory = nope
, renameExport = \_ _ _ -> return Nothing
}
where
nope = giveup "export not supported"
-- | Use for remotes that do not support imports.
class HasImportUnsupported a where
importUnsupported :: a
instance HasImportUnsupported (ParsedRemoteConfig -> RemoteGitConfig -> Annex Bool) where
importUnsupported = \_ _ -> return False
instance HasImportUnsupported (ImportActions Annex) where
importUnsupported = ImportActions
{ listImportableContents = nope
, importKey = Nothing
, retrieveExportWithContentIdentifier = nope
, storeExportWithContentIdentifier = nope
, removeExportWithContentIdentifier = nope
, removeExportDirectoryWhenEmpty = nope
, checkPresentExportWithContentIdentifier = \_ _ _ -> return False
}
where
nope = giveup "import not supported"
exportIsSupported :: ParsedRemoteConfig -> RemoteGitConfig -> Annex Bool
exportIsSupported = \_ _ -> return True
importIsSupported :: ParsedRemoteConfig -> RemoteGitConfig -> Annex Bool
importIsSupported = \_ _ -> return True
-- | Prevent or allow exporttree=yes and importtree=yes when
-- setting up a new remote, depending on the remote's capabilities.
adjustExportImportRemoteType :: RemoteType -> RemoteType
adjustExportImportRemoteType rt = rt { setup = setup' }
where
setup' st mu cp c gc = do
pc <- either giveup return . parseRemoteConfig c
=<< configParser rt c
let checkconfig supported configured configfield cont =
ifM (supported rt pc gc <&&> pure (not (thirdPartyPopulated rt)))
( case st of
Init
| configured pc && encryptionIsEnabled pc ->
giveup $ "cannot enable both encryption and " ++ fromProposedAccepted configfield
| otherwise -> cont
Enable oldc -> enable oldc pc configured configfield cont
AutoEnable oldc -> enable oldc pc configured configfield cont
, if configured pc
then giveup $ fromProposedAccepted configfield ++ " is not supported by this special remote"
else cont
)
checkconfig exportSupported exportTree exportTreeField $
checkconfig importSupported importTree importTreeField $
setup rt st mu cp c gc
enable oldc pc configured configfield cont = do
oldpc <- parsedRemoteConfig rt oldc
if configured pc /= configured oldpc
then giveup $ "cannot change " ++ fromProposedAccepted configfield ++ " of existing special remote"
else cont
-- | Adjust a remote to support exporttree=yes and/or importree=yes.
adjustExportImport :: Remote -> RemoteStateHandle -> Annex Remote
adjustExportImport r rs = do
isexport <- pure (exportTree (config r))
<&&> isExportSupported r
-- When thirdPartyPopulated is True, the remote
-- does not need to be configured with importTree to support
-- imports.
isimport <- pure (importTree (config r) || thirdPartyPopulated (remotetype r))
<&&> isImportSupported r
let r' = r
{ remotetype = (remotetype r)
{ exportSupported = if isexport
then exportSupported (remotetype r)
else exportUnsupported
, importSupported = if isimport
then importSupported (remotetype r)
else importUnsupported
}
}
if not isexport && not isimport
then return r'
else adjustExportImport' isexport isimport r' rs
adjustExportImport' :: Bool -> Bool -> Remote -> RemoteStateHandle -> Annex Remote
adjustExportImport' isexport isimport r rs = do
dbv <- prepdbv
ciddbv <- prepciddb
let versioned = versionedExport (exportActions r)
return $ r
{ exportActions = if isexport
then if isimport
then exportActionsForImport dbv ciddbv (exportActions r)
else exportActions r
else exportUnsupported
, importActions = if isimport
then importActions r
else importUnsupported
, storeKey = \k af p ->
-- Storing a key on an export could be implemented,
-- but it would perform unncessary work
-- when another repository has already stored the
-- key, and the local repository does not know
-- about it. To avoid unnecessary costs, don't do it.
if thirdpartypopulated
then giveup "remote is not populated by git-annex"
else if isexport
then giveup "remote is configured with exporttree=yes; use `git-annex export` to store content on it"
else if isimport
then giveup "remote is configured with importtree=yes and without exporttree=yes; cannot modify content stored on it"
else storeKey r k af p
, removeKey = \k ->
-- Removing a key from an export would need to
-- change the tree in the export log to not include
-- the file. Otherwise, conflicts when removing
-- files would not be dealt with correctly.
-- There does not seem to be a good use case for
-- removing a key from an export in any case.
if thirdpartypopulated
then giveup "dropping content from this remote is not supported"
else if isexport
then giveup "dropping content from an export is not supported; use `git annex export` to export a tree that lacks the files you want to remove"
else if isimport
then giveup "dropping content from this remote is not supported because it is configured with importtree=yes"
else removeKey r k
, lockContent = if versioned
then lockContent r
else Nothing
, retrieveKeyFile = \k af dest p ->
if isimport
then supportversionedretrieve k af dest p $
retrieveKeyFileFromImport dbv ciddbv k af dest p
else if isexport
then supportversionedretrieve k af dest p $
retrieveKeyFileFromExport dbv k af dest p
else retrieveKeyFile r k af dest p
, retrieveKeyFileCheap = if versioned
then retrieveKeyFileCheap r
else Nothing
, checkPresent = \k -> if versioned
then checkPresent r k
else if isimport
then anyM (checkPresentImport ciddbv k)
=<< getanyexportlocs dbv k
else if isexport
-- Check if any of the files a key
-- was exported to are present. This
-- doesn't guarantee the export
-- contains the right content,
-- if the remote is an export,
-- or if something else can write
-- to it. Remotes that have such
-- problems are made untrusted,
-- so it's not worried about here.
then anyM (checkPresentExport (exportActions r) k)
=<< getanyexportlocs dbv k
else checkPresent r k
-- checkPresent from an export is more expensive
-- than otherwise, so not cheap. Also, this
-- avoids things that look at checkPresentCheap and
-- silently skip non-present files from behaving
-- in confusing ways when there's an export
-- conflict (or an import conflict).
, checkPresentCheap = False
-- Export/import remotes can lose content stored on them in
-- many ways. This is not a problem with versioned
-- ones though, since they still allow accessing by Key.
-- And for thirdPartyPopulated, it depends on how the
-- content gets actually stored in the remote, so
-- is not overriddden here.
, untrustworthy =
if versioned || thirdPartyPopulated (remotetype r)
then untrustworthy r
else False
-- git-annex testremote cannot be used to test
-- import/export since it stores keys.
, mkUnavailable = return Nothing
, getInfo = do
is <- getInfo r
is' <- if isexport && not thirdpartypopulated
then do
ts <- map fromRef . exportedTreeishes
<$> getExport (uuid r)
return (is++[("exporttree", "yes"), ("exportedtree", unwords ts)])
else return is
return $ if isimport && not thirdpartypopulated
then (is'++[("importtree", "yes")])
else is'
}
where
thirdpartypopulated = thirdPartyPopulated (remotetype r)
-- exportActions adjusted to use the equivilant import actions,
-- which take ContentIdentifiers into account.
exportActionsForImport dbv ciddbv ea = ea
{ storeExport = \f k loc p -> do
db <- getciddb ciddbv
exportdb <- getexportdb dbv
oldks <- liftIO $ Export.getExportTreeKey exportdb loc
oldcids <- liftIO $ concat
<$> mapM (ContentIdentifier.getContentIdentifiers db rs) oldks
newcid <- storeExportWithContentIdentifier (importActions r) f k loc oldcids p
withExclusiveLock gitAnnexContentIdentifierLock $ do
liftIO $ ContentIdentifier.recordContentIdentifier db rs newcid k
liftIO $ ContentIdentifier.flushDbQueue db
recordContentIdentifier rs newcid k
, removeExport = \k loc ->
removeExportWithContentIdentifier (importActions r) k loc
=<< getkeycids ciddbv k
, removeExportDirectory = removeExportDirectoryWhenEmpty (importActions r)
-- renameExport is optional, and the remote's
-- implementation may lose modifications to the file
-- (by eg copying and then deleting) so don't use it
, renameExport = \_ _ _ -> return Nothing
, checkPresentExport = checkPresentImport ciddbv
}
prepciddb = do
lcklckv <- liftIO newEmptyTMVarIO
dbtv <- liftIO newEmptyTMVarIO
return (dbtv, lcklckv)
prepdbv = do
lcklckv <- liftIO newEmptyTMVarIO
dbv <- liftIO newEmptyTMVarIO
exportinconflict <- liftIO $ newTVarIO False
return (dbv, lcklckv, exportinconflict)
-- Only open the database once it's needed.
getciddb (dbtv, lcklckv) =
liftIO (atomically (tryReadTMVar dbtv)) >>= \case
Just db -> return db
-- let only one thread take the lock
Nothing -> ifM (liftIO $ atomically $ tryPutTMVar lcklckv ())
( do
db <- ContentIdentifier.openDb
ContentIdentifier.needsUpdateFromLog db >>= \case
Just v -> withExclusiveLock gitAnnexContentIdentifierLock $
ContentIdentifier.updateFromLog db v
Nothing -> noop
liftIO $ atomically $ putTMVar dbtv db
return db
-- loser waits for winner to open the db and
-- can then also use its handle
, liftIO $ atomically (readTMVar dbtv)
)
-- Only open the database once it's needed.
--
-- After opening the database, check if the export log is
-- different than the database, and update the database, to notice
-- when an export has been updated from another repository.
getexportdb (dbv, lcklckv, exportinconflict) =
liftIO (atomically (tryReadTMVar dbv)) >>= \case
Just db -> return db
-- let only one thread take the lock
Nothing -> ifM (liftIO $ atomically $ tryPutTMVar lcklckv ())
( do
db <- Export.openDb (uuid r)
updateexportdb db exportinconflict
liftIO $ atomically $ putTMVar dbv db
return db
-- loser waits for winner to open the db and
-- can then also use its handle
, liftIO $ atomically (readTMVar dbv)
)
getexportinconflict (_, _, v) = v
updateexportdb db exportinconflict =
Export.updateExportTreeFromLog db >>= \case
Export.ExportUpdateSuccess -> return ()
Export.ExportUpdateConflict -> do
warnExportImportConflict r
liftIO $ atomically $
writeTVar exportinconflict True
getanyexportlocs dbv k = do
db <- getexportdb dbv
liftIO $ Export.getExportTree db k
getfirstexportloc dbv k = do
getexportlocs dbv k >>= \case
[] -> giveup "unknown export location"
(l:_) -> return l
getexportlocs dbv k = do
db <- getexportdb dbv
liftIO $ Export.getExportTree db k >>= \case
[] -> ifM (atomically $ readTVar $ getexportinconflict dbv)
( giveup "unknown export location, likely due to the export conflict"
, return []
)
ls -> return ls
getkeycids ciddbv k = do
db <- getciddb ciddbv
liftIO $ ContentIdentifier.getContentIdentifiers db rs k
-- Keys can be retrieved using retrieveExport, but since that
-- retrieves from a path in the remote that another writer could
-- have replaced with content not of the requested key, the content
-- has to be strongly verified.
retrieveKeyFileFromExport dbv k _af dest p = ifM (isVerifiable k)
( do
l <- getfirstexportloc dbv k
retrieveExport (exportActions r) k l dest p
return MustVerify
, giveup $ "exported content cannot be verified due to using the " ++ decodeBS (formatKeyVariety (fromKey keyVariety k)) ++ " backend"
)
retrieveKeyFileFromImport dbv ciddbv k af dest p =
getkeycids ciddbv k >>= \case
(cid:_) -> do
l <- getfirstexportloc dbv k
void $ retrieveExportWithContentIdentifier (importActions r) l cid dest (pure k) p
return UnVerified
-- In case a content identifier is somehow missing,
-- try this instead.
[] -> if isexport
then retrieveKeyFileFromExport dbv k af dest p
else giveup "no content identifier is recorded, unable to retrieve"
-- versionedExport remotes have a key/value store, so can use
-- the usual retrieveKeyFile, rather than an import/export
-- variant. However, fall back to that if retrieveKeyFile fails.
supportversionedretrieve k af dest p a
| versionedExport (exportActions r) =
retrieveKeyFile r k af dest p
`catchNonAsync` const a
| otherwise = a
checkPresentImport ciddbv k loc =
checkPresentExportWithContentIdentifier
(importActions r)
k loc
=<< getkeycids ciddbv k