Trend clean

[admin]

This will log all daily values with their respective offsets. If the whole list does not fit, you can change line 17 and add an extra offset. Just make sure that this extra offset is divisible by 8.

Code:

infile = '/tmp/trends/t1.trend'
values = {}

ffi = require('ffi')

function stringtodouble(chunk)
  local dbl = ffi.new('double[1]')
  ffi.copy(dbl, chunk, 8)
  return dbl[ 0 ]
end

info = require('rrd').info(infile)

data = io.readfile(infile)
offset = info.header_size + (info['rra[0].rows'] + info['rra[1].rows']) * 8

offset = offset + 0 * 8

while true do
  chunk = data:sub(offset + 1, offset + 8)

  if #chunk == 8 then
    value = stringtodouble(chunk)

    -- skip NaN (empty/undefined value)
    if value == value then
      values[ #values + 1 ] = string.format('%d %.1f', offset, value)
    end
  else
    break
  end

  offset = offset + 8
end

text = table.concat(values, '\n')
log(text)