Support for time series data

[adyanth]

Support for time series data

[marcusolsson]

As I mentioned earlier

the query result needs to contain a time field and a number field

In your case, you seem to have neither :)

• SensorValue is a string. The plugin would need to support parsing strings as numbers which it currently doesn't. If this is important to you, please create a feature request.
• In your screenshot, you don't seem to extract the SensorUpdateTime. You'd need to add another JSON Path query referencing the property you'd like to use for the timestamp.

[adyanth]

Yeah, I already did that on a dashboard for the same data source with a custom JSON exporter (Here and here). That works good.
I wanted to do it only in grafana because I was planning to run the whole thing on a raspberry pi which is already overloaded with this, and don't think can handle prometheus too : ) + I don't need more than like 60 samples at best, so keeping historical data does not help. I think I can roll a JSON -> JSON stateful adapter to save those samples if I plan to use this.

Thanks for looking into this, greatly appreciated! Happy holidays!

[marcusolsson]

To graph data in Grafana, the query result needs to contain a time field and a number field. The plugin detects time fields by checking if it's a valid ISO 8601 string, or if it looks like a UNIX epoch.

Let me know if you have trouble graphing data with this plugin!

[adyanth]

Here is the sample data from the API below, and my JsonPath query is $[?(@.SensorName == "Physical Memory Used")].SensorValue. (I tried the whole object too, $[?(@.SensorName == "Physical Memory Used")])

The SensorUpdateTime is indeed in Unix epoch time.
This is what I get on Grafana:

After switching to table view:

With the full object:

Let me know if I am doing something wrong here and thanks for looking into this!

[
  {
    "SensorApp": "HWiNFO",
    "SensorClass": "System: MSI MS-7C92",
    "SensorName": "Virtual Memory Commited",
    "SensorValue": "13857",
    "SensorUnit": "MB",
    "SensorUpdateTime": 1609297850
  },
  {
    "SensorApp": "HWiNFO",
    "SensorClass": "System: MSI MS-7C92",
    "SensorName": "Virtual Memory Available",
    "SensorValue": "27028",
    "SensorUnit": "MB",
    "SensorUpdateTime": 1609297850
  },
  {
    "SensorApp": "HWiNFO",
    "SensorClass": "System: MSI MS-7C92",
    "SensorName": "Virtual Memory Load",
    "SensorValue": "33.8",
    "SensorUnit": "%",
    "SensorUpdateTime": 1609297850
  },
  {
    "SensorApp": "HWiNFO",
    "SensorClass": "System: MSI MS-7C92",
    "SensorName": "Physical Memory Used",
    "SensorValue": "10133",
    "SensorUnit": "MB",
    "SensorUpdateTime": 1609297850
  }
]

[adyanth]

Okay, I tried that. This recognizes the date format, but does not plot anything. When I said that JSON updates in real time, I meant that the JSON will only be for the current instance. It won't have data for the previous time instances.

So, I don't think this is possible with this data source, since I believe it is expecting the complete data to be sent over, rather than just the current data. My JSON source is sending data only for the current time instance, the next time you request, it would respond with new data.

[marcusolsson]

Oh I see. Yeah, this plugin doesn't keep state at all. The JSON response need to contain the entire time series. If you want to store historical data, then I agree that something like Prometheus would be a better option 💯