Making some or all SignalK Data Stale/Out of date after a period of time?

[mattnj1975]

Can i make data expire and become out of date?
I'm new to Signal K, i have built a few SenseESP sensors and everything works well, but data never expires... for example I have a shore power sensor which monitors AC voltage 230v...works fine... but when the voltage is removed (and the sensor powers down) then the data (230v AC) shows an valid in Signal K forever...even if it's days old... is that the same for all data? What if you have an old GPS position or SOG or COG and the GPS signal is lost....does it just consider the last position/speed etc as valid forever? am i missing some obvious here?
Thanks

[bradharley]

That’s normal.  Mine don’t reset until I restart the signalk server.  I am not sure how you are using the data, but you always have the timestamp and you could filter out old data.Brad Harley. — Sent from my iPhoneOn Oct 9, 2024, at 08:01, mattnj1975 ***@***.***> wrote: Can i make data expire and become out of date? I'm new to Signal K, i have built a few SenseESP sensors and everything works well, but data never expires... for example I have a shore power sensor which monitors AC voltage 230v...works fine... but when the voltage is removed (and the sensor powers down) then the data (230v AC) shows an valid in Signal K forever...even if it's days old... is that the same for all data? What if you have an old GPS position or SOG or COG and the GPS signal is lost....does it just consider the last position/speed etc as valid forever? am i missing some obvious here? Thanks —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[mattnj1975]

Thanks, i am using data in KIP can't see how to filter the data is that within Signal K somewhere?

[bradharley]

I am sure the developers will provide a more intelligent response but in the interim…What little I know of the design, it’s probably intended that the client throw away stale data.  There are lots of valid reasons you may want to retain the last data entry. There is no way I am aware of (I have not really looked though) to have a time to live for the data. You could do a couple of things off the top of my head..1- reach out to the author of Kip. 2-use node red to overwrite stale data with zero or a null value. 3- do something brute force like restart signalk when you lose your sensor. Brad Harley. — Sent from my iPhoneOn Oct 10, 2024, at 03:57, mattnj1975 ***@***.***> wrote: Thanks, i am using data in KIP can't see how to filter the data is that within Signal K somewhere? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[mattnj1975]

thanks for the reply...that all sounds nasty (other than contacting developer) nodeRed on all values would be a hell of a job... (i think) and forcing a restart! what if I an underway navigating! it seems crazy to me.... are we really saying that if I have say a GPS feed coming in with position data.... that GPS data stops, nothing will update... or time out, so I could have an emergency and be reading out a GPS position to coastguard that's lets say 12 hours old... I I would have no idea and it's still considered valid?!

[bradharley]

From a signalk perspective, all data is timestamped. So it is accurate.  I get your situation.  I believe the reason right place to validate this would be in the app— KIP in your case.  The other methods are really hacks. You could use opencpn.  It does timeout stale data as another option. I would expect the author of Kip would welcome your feedback.  Let us know how it turns out. Brad Harley. — Sent from my iPhoneOn Oct 10, 2024, at 07:47, mattnj1975 ***@***.***> wrote: thanks for the reply...that all sounds nasty (other than contacting developer) nodeRed on all values would be a hell of a job... (i think) and forcing a restart! what if I an underway navigating! it seems crazy to me.... are we really saying that if I have say a GPS feed coming in with position data.... that GPS data stops, nothing will update... or time out, so I could have an emergency and be reading out a GPS position to coastguard that's lets say 12 hours old... I I would have no idea and it's still considered valid?! —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[tkurki]

I think not having the option to have data timeout with a global mechanism is an omission that we should fix.

The picture is not quite black or white - there's value in having access to the last value as well as in not having to check for timestamps and freshness all over the place. Would you not want the last known position shown on a map, indicating that the data is not quite fresh? But when requesting data would you not want a mechanism that excludes stale data?

But I am sure we can work a better method out than how things are today.

[VladimirKalachikhin]

I think not having the option to have data timeout with a global mechanism is an omission that we should fix.

I applaud. It's only been five years...
You can see how this is done in the gpsdPROXY, the backend of the GaladrielMap.