High frequency interval tick - forced process state matching the interval's desired structure (optimal tuple instead of dict). Runs as an independent GenServer process. Send "state data" into GenServer.start_link(state_data)

How to use:

1. use Utils.IntervalTickHF, [opts] (see below for options)

2. define function callback_name which is called every frequency, with an extra option of :tick, and every interval with the option being :tock. Spec:

   callback_name(

   state_data :: term(),
   :tick | :tock,
   last_run_time :: number()

   ) :: {:ok, state_data :: term()}

Opts include:

• callback: atom() — REQUIRED — function to call on each interval/frequency
• tick: number() — REQUIRED - integer in the time_size matching get_time.

                 tick must be smaller than tock.  (i.e. 100 vs 1000).

• tock: number() — REQUIRED - integer in the time_size matching get_time

                 tock must be large than tick.

• get_time: fn() — how time is measured; defaults to System.system_time(:second)
• millis_factor: 1000 — a multiplier to convert time from get_time into millis.
• handle_interval: :hf_interval_tick — change the handle_info(:callback, ..) name — largely unecessary to adjust unless the default :hf_interval_tick collides with something else already being in handle_info(..)

Example:

defmodule SensorReader do

use IntervalTickHF,
  callback: :sample_power,
  get_time: System.system_time(:millisecond),
  interval: 1000,
  frequency: 10,
  millis_factor: 1

def sample_power({config, samples}, :tick, _) do
  {:ok, {config, [read_value(config) | samples]}}
end

def sample_power({config, samples}, :tock, _) do
  Report.Value.somehow( [read_value(config) | samples] |> normalize_samples())
  {:ok, {config, []}}
end

defp read_value(config), do: ...
defp normalize_samples(samples), do: ...

end

Started with:

SensorReader.start_link({%{config_data_here}, []}, name: :the_sensor)

Contributor: Brandon Gillespie