check_ssh_exec_addon

#!/usr/bin/lua

-- Copyright Julien Thomas < julthomas @ free.fr >
-- Copyright Zenetys < jthomas @ zenetys.com >
-- Author: Julien Thomas
-- Licence: MIT

local lc = require 'libcheck'
local lp = require 'libperfdata'
require 'print_r'

local default_parameter = {}
local data = {}
local perfdata = {}
local env = setmetatable(
    { lc = lc, lp = lp, default_parameter = default_parameter,
      data = data, perfdata = perfdata },
    { __index = _ENV })
local addon_code = {}

function load_addon(_, value)
    if lc.lfs.attributes(value, 'mode') ~= 'file' then
        if lc.lfs.attributes(lc.progdir..'/'..value, 'mode') == 'file' then
            value = lc.progdir..'/'..value
        else
            lc.die(lc.UNKNOWN, 'Addon not found: '..value)
        end
    end

    lc.debug('load addon: '..value)
    local code, err = loadfile(value, nil, env)
    if not code then
        lc.die(lc.UNKNOWN, 'Failed to load addon: '..err)
    end
    local success, err = pcall(code, 'init')
    if not success then
        lc.die(lc.UNKNOWN, 'Failed to run addon optsdef: '..err)
    end
    lc.optsdef.rebuild()
    table.insert(addon_code, { name = lc.basename(value), code = code })
    return value
end

function load_addon_array(_, value)
    for i in (value..','):gmatch('([^,]*),') do
        load_addon(_, i)
    end
    return value
end

lc.checkname = 'SSH-EXEC'
lc.shortdescr = 'Generic Nagios plugin to exec commands via SSH'

lc.opts = {
    parameter = {},
}

lc.optsdef = {
    { short = 'a', long = 'addon', help = 'Custom addon script', call = load_addon_array },
    { short = 'N', long = 'check-name', help = 'Set output prefix', call = function (o,v) lc.checkname = v; return v end },
    { short = 'H', long = 'host', help = 'SSH host to connect to' },
    { short = 'm', long = 'command', help = 'Bash code to execute (caller escape)' },
    { short = 'f', long = 'command-file', help = 'Bash script to execute' },
    { short = 's', long = 'ssh-command', help = 'Custom SSH command (caller escape)' },
    { short = 'b', long = 'bash-command', help = 'Custom bash command (caller escape)' },
    { short = 'o', long = 'ssh-option', help = 'Set indice for an ES backend', call = lc.setter_opt_array },
    { short = 'r', long = 'passthrough', help = 'Print stdout, exit with command status', call = lc.setter_opt_boolean },
    { short = 'p', long = 'parameter', help = 'Parameters (kv)', call = lc.setter_opt_kv },
    { short = 'w', long = 'warning', help = 'Generic warning threshold (array)', call = lc.setter_opt_array },
    { short = 'c', long = 'critical', help = 'Generic critical threshold (array)', call = lc.setter_opt_array },
    { short = 't', long = 'timeout', help = 'Global timeout (s)', call = lc.setter_opt_number },
}

lc.init_opts()

for k,v in pairs(default_parameter) do
    if lc.opts.parameter[k] == nil then
        lc.opts.parameter[k] = v
    end
end

-- build command
function sh_quote(value)
    return "'"..value:gsub("'", "'\\''").."'"
end
local shell_code = nil
if lc.opts.command_file and #lc.opts.command_file > 0 then
    if lc.lfs.attributes(lc.opts.command_file, 'mode') ~= 'file' then
        local candidate = lc.dirname(arg[0])..'/'..lc.opts.command_file
        if lc.lfs.attributes(candidate, 'mode') ~= 'file' then
            lc.die(lc.UNKNOWN, 'Addon not found: '..value)
        end
        lc.opts.command_file = candidate
    end
    shell_code = 'cat '..sh_quote(lc.opts.command_file)
elseif lc.opts.command and #lc.opts.command > 0 then
    shell_code = 'echo '..sh_quote(lc.opts.command)
end
if not shell_code then lc.die(lc.UNKNOWN, 'Nothing to execute') end
shell_code = shell_code..' | '
shell_code = shell_code..((lc.opts.ssh_command and #lc.opts.ssh_command > 0) and
    lc.opts.ssh_command or 'ssh')
for _,v in ipairs(lc.opts.ssh_option) do
    shell_code = shell_code..' -o '..sh_quote(v)
end
shell_code = shell_code..' '..sh_quote(lc.opts.host)..' '
shell_code = shell_code..((lc.opts.bash_command and #lc.opts.bash_command > 0) and
    lc.opts.bash_command or 'bash')

lc.pdebug('Shell code to execute: '..shell_code)

-- handle global timeout
if lc.opts.timeout then
    local global_timeout = os.time() + lc.opts.timeout
    debug.sethook(function()
        if os.time() >= global_timeout then
            debug.sethook()
            lc.die(lc.UNKNOWN, 'Killed by global timeout after '..lc.opts.timeout..'s')
        end
    end, '', 200)
end

-- run command, fill the result map
local pipe = io.popen(shell_code, 'r')
for line in pipe:lines() do
    lc.debug('line> '..line)
    if lc.opts.passthrough then print(line)
    else table.insert(data, line) end
end
local rc = { pipe:close() }
if lc.opts.passthrough then
    lc.on_exit_handlers = {}
    os.exit(rc[3])
elseif rc[3] ~= 0 then
    lc.die(lc.UNKNOWN, 'Failed to retrieve data, command status '..rc[3])
end

for _,v in ipairs(addon_code) do
    local success, err = pcall(v.code)
    if not success then
        lc.die(lc.UNKNOWN, "Failed to run addon '"..v.name.."' code: "..err)
    end
end

lc.dump(data, 'Dump data after addons')
lc.dump(perfdata, 'Dump perfdata')

-- set exit state and output from perfdatas if not already done by addon
if #perfdata > 0 then
    if not lc.exit_code then
        lc.exit_code = lp.compute_perfdata(perfdata)
    end
    if not lc.exit_message then
        lc.exit_message = lp.format_output(perfdata)..'|'..
            lp.format_perfdata(perfdata, true)
    end
end