--
-- default-rsyncssh.lua
--
--    Improved rsync - sync with rsync, but moves and deletes executed over ssh.
--    A (Layer 1) configuration.
--
-- Note:
--    this is infact just a configuration using Layer 1 configuration
--    like any other. It only gets compiled into the binary by default.
--    You can simply use a modified one, by copying everything into a
--    config file of yours and name it differently.
--
-- License: GPLv2 (see COPYING) or any later version
-- Authors: Axel Kittenberger <axkibe@gmail.com>
--
--

if not default
then
	error( 'default not loaded' );
end

if not default.rsync
then
	error( 'default.rsync not loaded' );
end

if default.rsyncssh
then
	error( 'default-rsyncssh already loaded' );
end

--
-- rsyncssh extends default.rsync
--
local rsyncssh = { default.rsync }

default.rsyncssh = rsyncssh

--
-- used to ensure there aren't typos in the keys
--
rsyncssh.checkgauge = {

	-- unsets the inherited value of from default.rsync
	target          =  false,
	onMove          =  true,

	-- rsyncssh users host and targetdir
	host            =  true,
	targetdir       =  true,
	sshExitCodes    =  true,
	rsyncExitCodes  =  true,

	-- ssh settings
	ssh = {
		binary       =  true,
		identityFile =  true,
		options      =  true,
		port         =  true,
		_extra       =  true
	},

	-- xargs settings
	xargs = {
		binary      =  true,
		delimiter   =  true,
		_extra      =  true
	}
}

--
-- Spawns rsync for a list of events
--
rsyncssh.action = function
(
	inlet
)
	local event, event2 = inlet.getEvent( )

	local config = inlet.getConfig( )

	-- makes move local on target host
	-- if the move fails, it deletes the source
	if event.etype == 'Move'
	then
		local path1 = config.targetdir .. event.path

		local path2 = config.targetdir .. event2.path

		path1 = "'" .. path1:gsub ('\'', '\'"\'"\'') .. "'"
		path2 = "'" .. path2:gsub ('\'', '\'"\'"\'') .. "'"

		log(
			'Normal',
			'Moving ',
			event.path,
			' -> ',
			event2.path
		)

		spawn(
			event,
			config.ssh.binary,
			config.ssh._computed,
			config.host,
			'mv',
			path1,
			path2,
			'||', 'rm', '-rf',
			path1
		)

		return
	end

	-- uses ssh to delete files on remote host
	-- instead of constructing rsync filters

	if event.etype == 'Delete'
	then
		if config.delete ~= true
		and config.delete ~= 'running'
		then
			inlet.discardEvent( event )

			return
		end

		-- gets all other deletes ready to be
		-- executed
		local elist = inlet.getEvents(
			function( e )
				return e.etype == 'Delete'
			end
		)

		-- returns the paths of the delete list
		local paths = elist.getPaths(
			function( etype, path1, path2 )
				if path2
				then
					return config.targetdir..path1, config.targetdir..path2
				else
					return config.targetdir..path1
				end
			end
		)

		-- ensures none of the paths is '/'
		for _, v in pairs( paths )
		do
			if string.match( v, '^%s*/+%s*$' )
			then
				log( 'Error', 'cowardly refusing to `rm -rf /` the target!' )

				terminate( -1 ) -- ERRNO
			end
		end

		log(
			'Normal',
			'Deleting list\n',
			table.concat( paths, '\n' )
		)

		local params = { }

		spawn(
			elist,
			config.ssh.binary,
			'<', table.concat(paths, config.xargs.delimiter),
			params,
			config.ssh._computed,
			config.host,
			config.xargs.binary,
			config.xargs._extra
		)

		return
	end

	--
	-- for everything else a rsync is spawned
	--
	local elist = inlet.getEvents(
		function( e )
			-- TODO use a table
			return(
				e.etype ~= 'Move'
				and e.etype ~= 'Delete'
				and e.etype ~= 'Init'
				and e.etype ~= 'Blanket'
			)
		end
	)

	local paths = elist.getPaths( )

	--
	-- removes trailing slashes from dirs.
	--
	for k, v in ipairs( paths )
	do
		if string.byte( v, -1 ) == 47
		then
			paths[k] = string.sub( v, 1, -2 )
		end
	end

	local sPaths = table.concat( paths, '\n' )

	local zPaths = table.concat( paths, '\000' )

	log(
		'Normal',
		'Rsyncing list\n',
		sPaths
	)

	spawn(
		elist,
		config.rsync.binary,
		'<', zPaths,
		config.rsync._computed,
		'--from0',
		'--files-from=-',
		config.source,
		config.host .. ':' .. config.targetdir
	)
end

-----
-- Called when collecting a finished child process
--
rsyncssh.collect = function
(
	agent,
	exitcode
)
	local config = agent.config

	if not agent.isList and agent.etype == 'Init'
	then
		local rc = config.rsyncExitCodes[exitcode]

		if rc == 'ok'
		then
			log('Normal', 'Startup of "',agent.source,'" finished: ', exitcode)
		elseif rc == 'again'
		then
			if settings('insist')
			then
				log( 'Normal', 'Retrying startup of "',agent.source,'": ', exitcode )
			else
				log( 'Error', 'Temporary or permanent failure on startup of "',
				agent.source, '". Terminating since "insist" is not set.' );
				terminate( -1 ) -- ERRNO
			end
		elseif rc == 'die'
		then
			log( 'Error', 'Failure on startup of "',agent.source,'": ', exitcode )
		else
			log( 'Error', 'Unknown exitcode on startup of "', agent.source,': "',exitcode )

			rc = 'die'
		end

		return rc
	end

	if agent.isList
	then
		local rc = config.rsyncExitCodes[ exitcode ]

		if rc == 'ok'
		then
			log( 'Normal', 'Finished (list): ', exitcode )
		elseif rc == 'again'
		then
			log( 'Normal', 'Retrying (list): ', exitcode )
		elseif rc == 'die'
		then
			log( 'Error',  'Failure (list): ', exitcode )
		else
			log( 'Error', 'Unknown exitcode (list): ', exitcode )

			rc = 'die'
		end
		return rc
	else
		local rc = config.sshExitCodes[exitcode]

		if rc == 'ok'
		then
			log( 'Normal', 'Finished ',agent.etype,' ',agent.sourcePath,': ',exitcode )
		elseif rc == 'again'
		then
			log( 'Normal', 'Retrying ',agent.etype,' ',agent.sourcePath,': ',exitcode )
		elseif rc == 'die'
		then
			log( 'Normal', 'Failure ',agent.etype,' ',agent.sourcePath,': ',exitcode )
		else
			log( 'Error', 'Unknown exitcode ',agent.etype,' ',agent.sourcePath,': ',exitcode )

			rc = 'die'
		end

		return rc
	end

end

--
-- checks the configuration.
--
rsyncssh.prepare = function
(
	config,
	level
)
	default.rsync.prepare( config, level + 1, true )

	if not config.host
	then
		error(
			'default.rsyncssh needs "host" configured',
			level
		)
	end

	if not config.targetdir
	then
		error(
			'default.rsyncssh needs "targetdir" configured',
			level
		)
	end

	--
	-- computes the ssh options
	--
	if config.ssh._computed
	then
		error(
			'please do not use the internal rsync._computed parameter',
			level
		)
	end

	local cssh = config.ssh;

	cssh._computed = { }

	local computed = cssh._computed

	local computedN = 1

	local rsyncc = config.rsync._computed

	if cssh.identityFile
	then
		computed[ computedN ] = '-i'

		computed[ computedN + 1 ] = cssh.identityFile

		computedN = computedN + 2

		if not config.rsync._rshIndex
		then
			config.rsync._rshIndex = #rsyncc + 1

			rsyncc[ config.rsync._rshIndex ] = '--rsh=ssh'
		end

		rsyncc[ config.rsync._rshIndex ] =
			rsyncc[ config.rsync._rshIndex ] ..
			' -i ' ..
			cssh.identityFile
	end

	if cssh.options
	then
		for k, v in pairs( cssh.options )
		do
			computed[ computedN ] = '-o'

			computed[ computedN + 1 ] = k .. '=' .. v

			computedN = computedN + 2

			if not config.rsync._rshIndex
			then
				config.rsync._rshIndex = #rsyncc + 1

				rsyncc[ config.rsync._rshIndex ] = '--rsh=ssh'
			end

			rsyncc[ config.rsync._rshIndex ] =
				table.concat(
					{
						rsyncc[ config.rsync._rshIndex ],
						' -o ',
						k,
						'=',
						v
					},
					''
				)
		end
	end

	if cssh.port
	then
		computed[ computedN ] = '-p'

		computed[ computedN + 1 ] = cssh.port

		computedN = computedN + 2

		if not config.rsync._rshIndex
		then
			config.rsync._rshIndex = #rsyncc + 1

			rsyncc[ config.rsync._rshIndex ] = '--rsh=ssh'
		end

		rsyncc[ config.rsync._rshIndex ] =
			rsyncc[ config.rsync._rshIndex ] .. ' -p ' .. cssh.port
	end

	if cssh._extra
	then
		for k, v in ipairs( cssh._extra )
		do
			computed[ computedN ] = v

			computedN = computedN  + 1
		end
	end

	-- appends a slash to the targetdir if missing
	if string.sub( config.targetdir, -1 ) ~= '/'
	then
		config.targetdir =
			config.targetdir .. '/'
	end

end

--
-- allow processes
--
rsyncssh.maxProcesses = 1

--
-- The core should not split move events
--
rsyncssh.onMove = true

--
-- default delay
--
rsyncssh.delay = 15


--
-- no default exit codes
--
rsyncssh.exitcodes = false

--
-- rsync exit codes
--
rsyncssh.rsyncExitCodes = default.rsyncExitCodes

--
-- ssh exit codes
--
rsyncssh.sshExitCodes = default.sshExitCodes

--
-- xargs calls configuration
--
-- xargs is used to delete multiple remote files, when ssh access is
-- available this is simpler than to build filters for rsync for this.
--
rsyncssh.xargs = {

	--
	-- the binary called ( on target host )
	--
	binary = '/usr/bin/xargs',

	--
	-- delimiter, uses null by default, you might want to override this for older
	-- by for example '\n'
	--
	delimiter = '\000',

	--
	-- extra parameters
	--
	_extra = { '-0', 'rm -rf' }
}

--
-- ssh calls configuration
--
-- ssh is used to move and delete files on the target host
--
rsyncssh.ssh = {

	--
	-- the binary called
	--
	binary = '/usr/bin/ssh',

	--
	-- if set adds this key to ssh
	--
	identityFile = nil,

	--
	-- if set adds this special options to ssh
	--
	options = nil,

	--
	-- if set connect to this port
	--
	port = nil,

	--
	-- extra parameters
	--
	_extra = { }
}