Transforms - are cumulative sums a possibility?

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1

I would like to sum a metric over time using Transforms, i.e. a cumulative sum. Is this at all possible?

Whilst you can plot a cumulative sum graph using the basic graphs in Kibana, it's cumulative over the date range selected. I'd like to be able to set a start date in effect in an index/transform output, and the transform produce the cumulative sum over time.

2

and to clarify - I know I could produce a single row of output with a sum total of a metric from input, but I am hoping to be able to produce a cumulative sum over time, i.e. per day or better still for each record that I add from my input (at it's timestamp.

Thanks in advance.