Apache beam windowing: consider late data but emit only one pane

Question

I would like to emit a single pane when the watermark reaches x minutes past the end of the window. This let\'s me ensure I handle some late data, but still only emit one pa

Answer 1

Thanks Guillem, in the end I used your answer to find this very useful link with lots of apache beam examples. From this I came up with the following solution:

 // We first specify to never emit any panes
 .triggering(Never.ever())

 // We then specify to fire always when closing the window. This will emit a
 // single final pane at the end of allowedLateness
 .withAllowedLateness(allowedLateness, Window.ClosingBehavior.FIRE_ALWAYS)
 .discardingFiredPanes())