statorio/script/publisher.lua

--  ___ _        _           _     
-- / __| |_ __ _| |_ ___ _ _(_)___ 
-- \__ \  _/ _` |  _/ _ \ '_| / _ \
-- |___/\__\__,_|\__\___/_| |_\___/
--
-- Caches the latest metrics during
-- collection and writes data files
-- on demand.


local this = {}

-- keep filename in case it needs to be deleted
-- after the setting is changed
this.filename = nil

-- local cache of metrics before publication
this.metrics = {}


this.init = function()
  this.setFilename(Settings.getRuntimeGlobal("statorio-filename"))
end

-- queue a metric to be published
this.addMetric = function(name, val)
  -- TODO
  -- option to swap bool to 1|0
  -- option to swap nil to 0

  this.metrics[name] = val
end

-- publish stored metrics
this.publish = function()
  if get_file_extension(this.filename) == "statsd" then
    this.publishStatsd()
  else
    this.publishJson()
  end

  -- reset local cache
  this.metrics = {}
end

this.publishStatsd = function()
  -- generate lines of "metric_name:value|g"
  statsdString = ""
  for key, val in pairs(this.metrics) do
    if type(val) == "string" then
      statsdString = statsdString..key..":"..val.."|s\n"
    else
      statsdString = statsdString..key..":"..val.."|g\n"
    end
  end

  game.write_file(this.filename, statsdString)
end

this.publishJson = function()
  -- generate json
  jsonString = game.table_to_json(this.metrics)

  -- write to disk
  game.write_file(this.filename, jsonString)
end

this.setFilename = function(filename)

  if this.filename ~= nil then
    -- remove old file first
    log("Deleting old stats file "..this.filename)
    game.remove_path(this.filename)
  end

  -- set as filename for subsequent writes
  this.filename = filename
end


return this