71 lines
2.0 KiB
Lua
71 lines
2.0 KiB
Lua
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--[[
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rrd.pipe - Lua 5.1 submodule for connecting to rrdtool in pipe mode
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Copyright (C) 2010 Bart Van Der Meerssche <bart.vandermeerssche@flukso.net>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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]]--
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local nixio = require 'nixio'
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local getfenv, setmetatable =
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getfenv, setmetatable
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module (...)
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local modenv = getfenv()
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--- Start an rrdtool server in pipe mode.
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--
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-- +----------+ +-----------+
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-- | | fd[4] ---> fd[3] | |
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-- | parent | | rrdtool |
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-- | | fd[5] <--- fd[6] | |
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-- +----------+ +-----------+
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--
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-- @return rrd.server (RS) object
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function start()
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local fd = {}
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fd[3], fd[4] = nixio.pipe()
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fd[5], fd[6] = nixio.pipe()
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local pid, code, err = nixio.fork()
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if pid and pid ~= 0 then -- parent
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fd[3]:close()
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fd[6]:close()
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fd[5]:setblocking(false)
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return setmetatable({pid = pid, fdr = fd[5], fdw = fd[4]}, {__index = modenv})
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elseif pid == 0 then -- child
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fd[4]:close()
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fd[5]:close()
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nixio.dup(fd[3], nixio.stdin)
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nixio.dup(fd[6], nixio.stdout)
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nixio.execp('rrdtool', '-')
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else -- error
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nixio.syslog("err", "Unable to fork(): " .. err)
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return nil, code, err
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end
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end
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--- Stop the rrdtool server.
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-- @param rrd.server (RS) object
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-- @return true
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function stop(RS)
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RS.fdr:close()
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RS.fdw:close()
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return nixio.kill(RS.pid, nixio.const.SIGKILL)
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end
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