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#!/usr/bin/lua
-- Metrics web server
-- Copyright (c) 2016 Jeff Schornick <jeff@schornick.org>
-- Copyright (c) 2015 Kevin Lyda <kevin@lyda.ie>
-- Licensed under the Apache License, Version 2.0
socket = require("socket")
-- get configs
local omit_zero_values = os.getenv("OMIT_ZERO_VALUES") == "1"
-- Parsing
function space_split(s)
local elements = {}
for element in s:gmatch("%S+") do
table.insert(elements, element)
end
return elements
end
function get_contents(filename)
local f = io.open(filename, "rb")
local contents = ""
if f then
contents = f:read "*a"
f:close()
end
return contents
end
-- Metric printing
function print_metric(metric, labels, value)
if type(value) == "nil" then
return
end
out:write(metric)
if labels then
out:write("{")
coma = ""
for label,value in pairs(labels) do
out:write(coma, label, '="', value, '"')
coma = ","
end
out:write("}")
end
out:write(" ", value, "\n")
end
function metric(name, mtype, labels, value)
out:write("# TYPE ", name, " ", mtype, "\n")
-- omit_zero_vales config supress time series always being zero
local printall = not (mtype == "counter" and omit_zero_values)
local outputter = function(labels, value)
if printall or tonumber(value) ~= 0 then
print_metric(name, labels, value)
end
end
if value then
outputter(labels, value)
end
return outputter
end
function timed_scrape(collector)
local start_time = socket.gettime()
local success = 1
local status, err = pcall(collector.scrape)
if not status then
success = 0
io.stderr:write(err .. '\n')
end
return (socket.gettime() - start_time), success
end
function run_all_collectors(collectors)
local metric_duration = metric("node_scrape_collector_duration_seconds", "gauge")
local metric_success = metric("node_scrape_collector_success", "gauge")
for _,cname in pairs(collectors) do
if col_mods[cname] ~= nil then
local duration, success = timed_scrape(col_mods[cname])
local labels = {collector=cname}
metric_duration(labels, duration)
metric_success(labels, success)
end
end
end
-- Web server-specific functions
function handle_request(env)
-- use buffered output instead uhttpd.send()
out = io.open("/proc/self/fd/1", "a+")
out:setvbuf("full")
if env.PATH_INFO ~= '/metrics' then
out:write("Status: 404 Not Found\r\n")
out:write("Server: lua-metrics\r\n")
out:write("Content-Type: text/plain\r\n\r\n")
out:write("ERROR: File Not Found.")
else
out:write("Status: 200 OK\r\n")
out:write("Server: lua-metrics\r\n")
out:write("Content-Type: text/plain; version=0.0.4\r\n\r\n")
local cols = {}
for c in env.QUERY_STRING:gmatch("collect[^=]*=([^&]+)") do
cols[#cols+1] = c
end
if #cols == 0 then
cols = col_names
end
run_all_collectors(cols)
end
out:flush()
end
-- Main program
col_mods = {}
col_names = {}
ls_fd = io.popen("ls -1 /usr/lib/lua/prometheus-collectors/*.lua")
for c in ls_fd:lines() do
c = c:match("([^/]+)%.lua$")
col_mods[c] = require('prometheus-collectors.'..c)
col_names[#col_names+1] = c
end
ls_fd:close()
if arg ~= nil then
out = io.output()
run_all_collectors(col_names)
end
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