Support for SK history api

[tkurki]

Both signalk-to-influxdb and signalk-to-influxdb2 support Signal K History API. I started adding the openapi description for the history API.

By using the history API Kip could retrieve the data for the historical datasets and start with full graphs instead of starting to accumulate the data when Kip is loaded.

History API would also allow navigating the graph datasets, back and forth in time and zooming in and out.

[godind]

How does that work technically?
Storage is in InfluxDb, integration is handled by an SK plugin and it's all exposed as the SK Playback API ?

[tkurki]

Otherwise correct but not the Playback api, that is different. See the link in my previous post.

[godind]

More for personal knowledge: is history a replacement for playback? I'd love to understand the different purposes/roadmap for each.

[tkurki]

The difference should be pretty clear from the description?

Playback = ”hey server start playing back all the data from time xx onwards”
History api = ”hey server give me data for paths x and y from time xx to yy”

[godind]

That's it? Playback sounds simpler and better suited for KIP.

[tkurki]

Playback is for streaming all data in real time or slowed or speeded up, not for retrieving specific time series data.

[irjudson]

The subtle difference is in data boundary parameters and return style (stream vs batch).
This might/could simplify all widgets by creating a new "simple" widget "graph over time" that connects to the history api and just displays "now - graph size" queries every update.

that's different from "playback my route from last monday" -- at least to me, but, does that make it any more or less clear to you @godind ?

PS - I'm about to try and join the active signalk/kip dev - is there any discord like community for real-time discussions>

[godind]

Hi! Join the signal K #KIP Discord channel. We can chat there. I'll take all the help I can!

[godind]

@irjudson lets chat on Discord. Im not sure I understand.