influxdb library

[Matt]

I am sharing a way to send easily object values to influxdb.

Update server and database name before using it.
influx_clim send object with tag "influx_clim"
add "influx_clim()" to a schedule for automatic export

Code:

require 'ltn12'
require 'socket.http'
local https = require("ssl.https")

local influxdb_debug = true
local influxdb_server = "https://user:pass@host:8086"
local influxdb_database = "db_name"

local influxdb_buffer

--function used to convert object name (logicmachine) to valid influxdb field key
function influxdb_normalize(name)
 return string.gsub(name,  " ", "_")
end

--add an entry to be send
function influxdb_add(line_protocol)

 if (influxdb_debug) then
   alert("influxdb_add start")
 end
 
 if influxdb_buffer then
   influxdb_buffer = influxdb_buffer .. "\n" .. tostring(line_protocol)
 else
   influxdb_buffer =  tostring(line_protocol)
 end
 
 if (influxdb_debug) then
   alert("influxdb_add done")
 end  
end


function influxdb_current()
 return influxdb_buffer
end


-- send the buffer to influxdb
function influxdb_send()
 
 if (influxdb_debug) then
   alert("influxdb_send start")
 end
 
 local request_insert_url = influxdb_server .. "/write?db=" .. influxdb_database
 
--  log(influxdb_buffer)
 
 local response_body = { }
 local body, code, hdrs, stat = https.request
 {
   url = request_insert_url;
   verify = "none";
   method = "POST";
   headers =
   {
     ["Content-Length"] = #influxdb_buffer;
   };
   source = ltn12.source.string(influxdb_buffer);
   sink = ltn12.sink.table(response_body);
 }

 influxdb_buffer = nil

 if (code ~= 204) then
   alert("influxdb error code:" .. tostring(code))
   alert("influxdb_send http post error")
 end

 if (influxdb_debug) then
      alert("influxdb_send done")
 end
 
end


--export all objects with tag "influx_clim"
function influx_clim()
 
 local values=grp.tag("influx_clim")


 if (influxdb_debug) then
   alert("influx_cilm start")
 end

 local txtvalues = ""

 for index, id in ipairs(values) do
   -- add separator
   if (#txtvalues>0) then
     txtvalues = txtvalues .. ","
   end
 
   -- calculate value to be sent
   if (type(id["data"])=="boolean") then
     value=id["data"] and 1 or 0
   else
     value=id["data"]
   end
   -- add key value pair
   txtvalues = txtvalues .. influxdb_normalize(id["name"]) .. "=" .. value
 end

 influxdb_add("clim " .. txtvalues)
 influxdb_send()

 if (debug) then
   alert("influx_cilm end")
 end
end