Reading trends from RRD in Lua

[Domoticatorino]

Please paste here content of your user.trends_pro library and how you are using it. I will check.

Code:

-- This function prepare export table and .csv file from defined range
function trend_export(name, dates, mode, timestampType)
 
 require('trends')

 -- detect timeShift
 function detectTimeShift(t0, t1)
 t0_isdst, t1_isdst = os.date('*t', t0).isdst, os.date('*t', t1).isdst

   if (t0_isdst ~= t1_isdst) then
     if (t1_isdst) then
       -- change to summertime
       return 1
     else
       -- change to wintertime
       return 2
     end
   else
     return false
   end
 end

 -- Convert word "now" in "start" to data table
 if type(dates['start']) == "string" then
   if dates['start'] == "now" then dates['start'] = os.date("*t", os.time())
   elseif dates['start'] == "yesterday" then dates['start'] = os.date("*t", os.time()-24*3600)
   elseif dates['start'] == "week_ago" then dates['start'] = os.date("*t", os.time()-7*24*3600)
   elseif dates['start'] == "month_ago" then dates['start'] = os.date("*t", os.time()-30*24*3600)
   elseif dates['start'] == "year_ago" then dates['start'] = os.date("*t", os.time()-365*24*3600)
   end
 end

 -- Convert word "now" in "end" to data table
 if type(dates['end']) == "string" then
   if dates['end'] == "now" then dates['end'] = os.date("*t", os.time())
   elseif dates['end'] == "yesterday" then dates['end'] = os.date("*t", os.time()-24*3600)
   elseif dates['end'] == "week_ago" then dates['end'] = os.date("*t", os.time()-7*24*3600)
   elseif dates['end'] == "month_ago" then dates['end'] = os.date("*t", os.time()-30*24*3600)
   elseif dates['end'] == "year_ago" then dates['end'] = os.date("*t", os.time()-365*24*3600)
   end
 end          

 -- Start and end in unix time
 starttime = os.time(dates['start'])
 endtime = os.time(dates['end'])

 -- Invert "start" and "end" when "end" is smaller than "start"
 if starttime > endtime then
   _ = dates['start']
   dates['start'] = dates['end']
   dates['end'] = _
 end

 -- Read trend resolution from DB
 resolution = db:getlist("SELECT resolution*60 FROM trends WHERE name='" .. name .. "'")[1]

 -- Prepare a table with the data which include the whole data from specified range
 if resolution then
     -- Expand a range with a one more day if there is some data in the last day
   if (os.date("%H", endtime)*3600 + os.date("%M", endtime)*60) >= resolution then
     dates['end'].day = dates['end'].day + 1
     raw_data = trends.fetch(name, dates, resolution)
   else
     raw_data = trends.fetch(name, dates, resolution)
   end

   start = 1
   data = {}
   start_timestamp = os.time(dates['start']) + resolution
   -- Cut the data and prepare a table with the data only from specified range
   offset = 0
   skip = 0
   k = 1
   while k <= #raw_data do
     v = raw_data[k]
     
     if k == 1 then last_timestamp = start_timestamp else last_timestamp = current_timestamp end
     current_timestamp = start_timestamp + (k-1) * resolution + offset
           
     timeShiftStatus = detectTimeShift(last_timestamp, current_timestamp)
     if timeShiftStatus then
       if timeShiftStatus == 1 then -- winter->summer
         skip = 6 -- skip 1 hour empty data
         offset = offset - 3600
       elseif timeShiftStatus == 2 then -- summer->winter
         offset = offset + 3600
       end
     end
     
     -- Add to new table only records from specified range
     if current_timestamp >= starttime and current_timestamp <= endtime then
       if timestampType == 'unixepoch' then data[start] = {current_timestamp, v}
       else data[start] = {os.date('%Y.%m.%d %H:%M:%S', current_timestamp), v} end
       start = start+1
     end

     k = k + 1 + skip
     skip = 0
   end
   
   if mode == 'csv' then
     -- Prepare .csv file
     for k,v in ipairs(data) do      
       data[k] = table.concat(data[k], ",")
     end

       csv = "timestamp, value\r\n" .. table.concat(data, "\r\n")
     return name, csv
   elseif mode == 'table' then
     return name, data
   end
 else
     alert('There is no trend with such a name')
 end
 
end