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seyren

Seyren trigger alert if value is null

I try to trigger a Seyren alert if the value received is null, but can't find a way to do so.

I have read several answers, like here and also here which says that it should be possible with the Allow no data checkbox.

However, what should I put into the field Warn level and Error level, since those fields are useless though mandatory?

Thanks for your help!

Solution

  • The way I've done this before is to use the transformNull function to switch a null value with something else which you can then alert on.

    For example, if I always expect my values to be 0 or greater and null would signal a problem I'd use a target of transformNull(my.target.string,-1). I can then use a warn value of -0.5 and error value of -1 to trigger an alert when there's a null value.

    The value you choose to switch null with will vary depending on the data you've got but hopefully you should be able to find something.