Push Forecast data as past data

The current system that I’m working with has prometheus exporters and services reading from it. I now need to push forecast values of a metric to the prometheusDB so that the downstream system works seamlessly doing its job so that it do not need to know if the data was real time or predicted.

For this to work I would need to get a prediction with values into the future, perform an offset and push them to prometheusDB as if they were from the past: prediction → [t, t1, t2, t3] would become in prometheusDB [t=t-3, t1=t1-3, t2=t2+3, t3=t3-3]. This would allow me two have the actual average from the past 3 time units of the metric in real time and the predicted average in the next 3 time units available in real time.

I don’t think that it is a exporter itself, is there a way to achieve this?