问题
In the documentation of FlinkCEP, I found that I can enforce that a particular event doesn't occur between two other events using notFollowedBy or notNext.
However, I was wondering If I could detect the absence of a certain event after a time X. For example, if an event A is not followed by another event A within 10 seconds, fire an alert or do something.
Could be possible to define a FlinkCEP pattern to capture that situation?
Thanks in advance, Humberto
回答1:
Although Flink CEP does not support notFollowedBy at the end of a Pattern, there is a way to implement this by exploiting the timeout feature.
The Flink training includes an exercise where the objective is to identify taxi rides with a START event that is not followed by an END event within two hours. You'll find a solution to this exercise that uses CEP here.
The main idea would be to define a Pattern of A followed by A within 10 seconds, and then capture the case where this times out.
来源：https://stackoverflow.com/questions/60730969/detect-absence-of-a-certain-event