git-annex/Assistant/MakeRemote.hs

{- git-annex assistant remote creation utilities
 -
 - Copyright 2012, 2013 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Assistant.MakeRemote where

import Assistant.Common
import Assistant.Ssh
import Assistant.Sync
import qualified Types.Remote as R
import qualified Remote
import Remote.List
import qualified Remote.Rsync as Rsync
import qualified Git
import qualified Git.Command
import qualified Command.InitRemote
import Logs.UUID
import Logs.Remote
import Git.Remote
import Config
import Config.Cost
import Creds

import qualified Data.Text as T
import qualified Data.Map as M

type RemoteName = String

{- Sets up and begins syncing with a new ssh or rsync remote. -}
makeSshRemote :: Bool -> SshData -> Maybe Cost -> Assistant Remote
makeSshRemote forcersync sshdata mcost = do
	r <- liftAnnex $
		addRemote $ maker (sshRepoName sshdata) sshurl
	liftAnnex $ maybe noop (setRemoteCost r) mcost
	syncRemote r
	return r
  where
	rsync = forcersync || rsyncOnly sshdata
	maker
		| rsync = makeRsyncRemote
		| otherwise = makeGitRemote
	sshurl = T.unpack $ T.concat $
		if rsync
			then [u, h, T.pack ":", sshDirectory sshdata, T.pack "/"]
			else [T.pack "ssh://", u, h, d, T.pack "/"]
	  where
		u = maybe (T.pack "") (\v -> T.concat [v, T.pack "@"]) $ sshUserName sshdata
		h = sshHostName sshdata
		d
			| T.pack "/" `T.isPrefixOf` sshDirectory sshdata = sshDirectory sshdata
			| T.pack "~/" `T.isPrefixOf` sshDirectory sshdata = T.concat [T.pack "/", sshDirectory sshdata]
			| otherwise = T.concat [T.pack "/~/", sshDirectory sshdata]
	
{- Runs an action that returns a name of the remote, and finishes adding it. -}
addRemote :: Annex RemoteName -> Annex Remote
addRemote a = do
	name <- a
	void remoteListRefresh
	maybe (error "failed to add remote") return
		=<< Remote.byName (Just name)

{- Inits a rsync special remote, and returns its name. -}
makeRsyncRemote :: RemoteName -> String -> Annex String
makeRsyncRemote name location = makeRemote name location $ const $ void $
	go =<< Command.InitRemote.findExisting name
  where
  	go Nothing = setupSpecialRemote name Rsync.remote config
		(Nothing, Command.InitRemote.newConfig name)
	go (Just (u, c)) = setupSpecialRemote name Rsync.remote config (Just u, c)
	config = M.fromList
		[ ("encryption", "shared")
		, ("rsyncurl", location)
		, ("type", "rsync")
		]

type SpecialRemoteMaker = RemoteName -> RemoteType -> R.RemoteConfig -> Annex RemoteName

{- Inits a new special remote. The name is used as a suggestion, but
 - will be changed if there is already a special remote with that name. -}
initSpecialRemote :: SpecialRemoteMaker
initSpecialRemote name remotetype config = go 0
  where
	go :: Int -> Annex RemoteName
	go n = do
		let fullname = if n == 0  then name else name ++ show n
		r <- Command.InitRemote.findExisting fullname
		case r of
			Nothing -> setupSpecialRemote fullname remotetype config
				(Nothing, Command.InitRemote.newConfig fullname)
			Just _ -> go (n + 1)

{- Enables an existing special remote. -}
enableSpecialRemote :: SpecialRemoteMaker
enableSpecialRemote name remotetype config = do
	r <- Command.InitRemote.findExisting name
	case r of
		Nothing -> error $ "Cannot find a special remote named " ++ name
		Just (u, c) -> setupSpecialRemote name remotetype config (Just u, c)

setupSpecialRemote :: RemoteName -> RemoteType -> R.RemoteConfig -> (Maybe UUID, R.RemoteConfig) -> Annex RemoteName
setupSpecialRemote name remotetype config (mu, c) = do
	{- Currently, only 'weak' ciphers can be generated from the
	 - assistant, because otherwise GnuPG may block once the entropy
	 - pool is drained, and as of now there's no way to tell the user
	 - to perform IO actions to refill the pool. -}
	(c', u) <- R.setup remotetype mu $
		M.insert "highRandomQuality" "false" $ M.union config c
	describeUUID u name
	configSet u c'
	return name

{- Returns the name of the git remote it created. If there's already a
 - remote at the location, returns its name. -}
makeGitRemote :: String -> String -> Annex RemoteName
makeGitRemote basename location = makeRemote basename location $ \name ->
	void $ inRepo $ Git.Command.runBool
		[Param "remote", Param "add", Param name, Param location]

{- If there's not already a remote at the location, adds it using the
 - action, which is passed the name of the remote to make.
 -
 - Returns the name of the remote. -}
makeRemote :: String -> String -> (RemoteName -> Annex ()) -> Annex RemoteName
makeRemote basename location a = do
	g <- gitRepo
	if not (any samelocation $ Git.remotes g)
		then do
			
			let name = uniqueRemoteName basename 0 g
			a name
			return name
		else return basename
  where
	samelocation x = Git.repoLocation x == location

{- Generate an unused name for a remote, adding a number if
 - necessary.
 -
 - Ensures that the returned name is a legal git remote name. -}
uniqueRemoteName :: String -> Int -> Git.Repo -> RemoteName
uniqueRemoteName basename n r
	| null namecollision = name
	| otherwise = uniqueRemoteName legalbasename (succ n) r
  where
	namecollision = filter samename (Git.remotes r)
	samename x = Git.remoteName x == Just name
	name
		| n == 0 = legalbasename
		| otherwise = legalbasename ++ show n
	legalbasename = makeLegalName basename

{- Finds a CredPair belonging to any Remote that is of a given type
 - and matches some other criteria.
 -
 - This can be used as a default when another repository is being set up
 - using the same service.
 -
 - A function must be provided that returns the CredPairStorage
 - to use for a particular Remote's uuid.
 -}
previouslyUsedCredPair
	:: (UUID -> CredPairStorage)
	-> RemoteType
	-> (Remote -> Bool)
	-> Annex (Maybe CredPair)
previouslyUsedCredPair getstorage remotetype criteria =
	getM fromstorage =<< filter criteria . filter sametype <$> remoteList
  where
	sametype r = R.typename (R.remotetype r) == R.typename remotetype
	fromstorage r = do
		let storage = getstorage (R.uuid r)
		getRemoteCredPair (R.config r) storage