.. include:: _controller_substitutions.repl

.. _C016_page:

|C016_typename|
==================================================

|C016_shortinfo|

Controller details
------------------

Type: |C016_type|

Name: |C016_name|

Status: |C016_status|

GitHub: |C016_github|_

Maintainer: |C016_maintainer|

Change log
----------

.. versionchanged:: 2.0
  ...

  |added| 2019/04/05
  Initial pre-alpha version of this plugin.

Description
-----------

This controller is a cache layer to collect data while not connected to a network.

The data will first be stored in RTC memory, which will survive a crash/reboot and even an OTA update.

If this RTC buffer is full, it will be flushed to whatever is set here as storage.

Data Format
-----------

Each time a plugin sends data to this controller, a sample set is stored.

A typical sample set contains:

- UNIX timestamp
- task index delivering the data
- 4 float values

Storage
-------

The controller can save the samples from RTC memory to several places on the flash:

- Files on SPIFFS
- Part reserved for OTA update (TODO)
- Unused flash after the partitioned space (TODO)

Data Delivery
-------------

The controller can deliver the data to:

- Upload bin files to some server (HTTP post?) (TODO)
- Provide a sample to any connected controller (TODO)
- Do nothing and let some extern host pull the data from the node. (TODO)
- JavaScript to process the data inside the browser. (TODO)
- Feed it to some plugin (e.g. a display to show a chart) (TODO)