git-annex/Command/Transferrer.hs
Joey Hess 04c12aa6df
custom protocol for transferrer
Rather than using Read/Show, which would force me to preserve data types
into the future.

I considered just deriving json and sending that, but I don't much like
deriving json with data types that have named constructors (like Key
does) because again it locks in data type details.

So instead, used SimpleProtocol, with a fairly complex and unreadable
protocol. But it is as efficient as the p2p protocol at least, and as
future proof.

(Writing my own custom json instances would have worked but I thought
of it too late and don't want to do all the work twice. The only real
benefit might be that aeson could be faster.)

Note that, when a new protocol request type is added later, git-annex
trying to use it will cause the git-annex transferrer to display a
protocol error message. That seems ok; it would only happen if a new
git-annex found an old version of itself in PATH or the program
file. So it's unlikely, and all it can do anyway is display an error.
(The error message could perhaps be improved..)

This commit was sponsored by Jack Hill on Patreon.
2020-12-09 16:13:59 -04:00

120 lines
3.9 KiB
Haskell

{- git-annex command
-
- Copyright 2012-2020 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.Transferrer where
import Command
import qualified Annex
import Annex.Content
import Logs.Location
import Annex.Transfer
import qualified Remote
import Utility.SimpleProtocol (dupIoHandles)
import qualified Database.Keys
import Annex.BranchState
import Types.Messages
import Annex.TransferrerPool
import Types.Transferrer
import qualified Utility.SimpleProtocol as Proto
cmd :: Command
cmd = command "transferrer" SectionPlumbing "transfers content"
paramNothing (withParams seek)
seek :: CmdParams -> CommandSeek
seek = withNothing (commandAction start)
start :: CommandStart
start = do
enableInteractiveBranchAccess
(readh, writeh) <- liftIO dupIoHandles
let outputwriter v = do
hPutStrLn writeh $
unwords $ Proto.formatMessage $ TransferOutput v
hFlush writeh
let outputresponsereader = do
l <- hGetLine readh
return $ case Proto.parseMessage l of
Just (TransferSerializedOutputResponse r) -> Just r
Nothing -> Nothing
Annex.setOutput $ SerializedOutput outputwriter outputresponsereader
runRequests readh writeh runner
stop
where
runner (UploadRequest _ key (TransferAssociatedFile file)) remote =
-- This is called by eg, Annex.Transfer.upload,
-- so caller is responsible for doing notification,
-- and for retrying.
upload' (Remote.uuid remote) key file noRetry
(Remote.action . Remote.storeKey remote key file)
noNotification
runner (DownloadRequest _ key (TransferAssociatedFile file)) remote =
-- This is called by eg, Annex.Transfer.download
-- so caller is responsible for doing notification
-- and for retrying.
let go p = getViaTmp (Remote.retrievalSecurityPolicy remote) (RemoteVerify remote) key file $ \t -> do
Remote.verifiedAction (Remote.retrieveKeyFile remote key file (fromRawFilePath t) p)
in download' (Remote.uuid remote) key file noRetry go
noNotification
runner (AssistantUploadRequest _ key (TransferAssociatedFile file)) remote =
notifyTransfer Upload file $
upload' (Remote.uuid remote) key file stdRetry $ \p -> do
tryNonAsync (Remote.storeKey remote key file p) >>= \case
Left e -> do
warning (show e)
return False
Right () -> do
Remote.logStatus remote key InfoPresent
return True
runner (AssistantDownloadRequest _ key (TransferAssociatedFile file)) remote =
notifyTransfer Download file $
download' (Remote.uuid remote) key file stdRetry $ \p ->
getViaTmp (Remote.retrievalSecurityPolicy remote) (RemoteVerify remote) key file $ \t -> do
r <- tryNonAsync (Remote.retrieveKeyFile remote key file (fromRawFilePath t) p) >>= \case
Left e -> do
warning (show e)
return (False, UnVerified)
Right v -> return (True, v)
-- Make sure we get the current
-- associated files data for the key,
-- not old cached data.
Database.Keys.closeDb
return r
runRequests
:: Handle
-> Handle
-> (TransferRequest -> Remote -> Annex Bool)
-> Annex ()
runRequests readh writeh a = go Nothing Nothing
where
go lastremoteoruuid lastremote = unlessM (liftIO $ hIsEOF readh) $ do
l <- liftIO $ hGetLine readh
case Proto.parseMessage l of
Just tr -> do
let remoteoruuid = transferRequestRemote tr
-- Often the same remote will be used
-- repeatedly, so cache the last one to
-- avoid looking up repeatedly.
mremote <- if lastremoteoruuid == Just remoteoruuid
then pure lastremote
else case remoteoruuid of
TransferRemoteName n ->
eitherToMaybe <$> Remote.byName' n
TransferRemoteUUID u ->
Remote.byUUID u
case mremote of
Just remote -> do
sendresult =<< a tr remote
go (Just remoteoruuid) mremote
Nothing -> transferrerProtocolError l
Nothing -> transferrerProtocolError l
sendresult b = liftIO $ do
hPutStrLn writeh $
unwords $ Proto.formatMessage $ TransferResult b
hFlush writeh