Issue with Widgets Displaying Incorrect Values During System Downtime

[Blackdragon]

I have noticed that some widgets display active values even when the system is down. For example, data obtained from a laptop shows all values as present despite the device being OFF; however, it does not provide real-time values. Although the fetch timing is set to 10 seconds, the issue persists

[Blackdragon]

anyone can assist on this

[doren765]

Hello,

You've hit upon a common problem in systems monitoring and widget display: the difference between "last known good value" and "real-time data." Here's a breakdown of why this happens and how to address it:

Understanding the Issue

Caching/Persistence:
Many widgets or monitoring systems cache or store the last successfully retrieved data. This is done for efficiency and to provide some information even when the source is temporarily unavailable.
When your laptop is off, the widget isn't receiving new data, but it's still displaying the last values it successfully fetched.
Lack of "Heartbeat" or Status Check:
A robust system should not only fetch data but also verify the data source's status.
Without a "heartbeat" (a regular check to see if the laptop is online), the widget has no way of knowing the data is stale.
Fetch Timing vs. Data Validity:
The 10-second fetch timing only dictates how often the widget attempts to retrieve data. It doesn't guarantee the data's validity.
If the laptop is off, the fetch will fail, but the cached data will remain.
Widget Design:
The widget may be designed to keep displaying the last known data, until a specific error code is returned. Or it may not be designed to handle device offline states at all.
Solutions

Implement a Heartbeat Mechanism:
The widget or monitoring system should periodically send a "ping" or other status check to the laptop.
If the laptop doesn't respond within a certain time, the widget should display an "offline," "unavailable," or "stale data" indicator.
Data Age Tracking:
Store a timestamp with each data point.
The widget should compare the current time with the data's timestamp. If the difference exceeds a threshold (e.g., 15 seconds), the widget should indicate stale data.
Error Handling and Display:
When a fetch fails (e.g., due to a network error or the laptop being off), the widget should display an error message instead of the cached data.
The error message should be informative, such as "Device offline" or "Connection failed".
Clear Caching/Persistence: E-ZPassNJ
Provide an option to manually clear the widget's cache.
Program the widget to clear the cache when a device offline state is detected.
Status Indicator:
Add a clear status indicator, such as a green dot for online and a red dot for offline, to the widget.
Data validity checks:
If the returned data is all zero's, or some other obviously invalid data, the widget should be able to recognize this, and display an error.

Best Regards

[Blackdragon]

thanks, i have noticed there was a ping template which i used. it is working fine now