Comparing a value of reduce expression with a constant in a template

Grafana Alerting
1

I have a prometheus query that returns positive values tracking how many days left until X expires and -1 if it has already expired.

I have an alert rule that uses this query and a ‘Reduce’ expression with “Last” function. (the expression is called “last”.

I want to compare the value of $last and produce “expired” string when the value is negative.

I have the following added to an annotation:

{{ if lt $values.last.Value 0}}expired{{end}}

But it doesn’t work and I get the following error:

error executing template [snip]
at <lt $values.last.Value 0>: error calling lt: incompatible types for comparison"

On the other hand when I tried comparing values from two different expressions - it worked:

{{ if lt $values.now.Value $values.before.Value}}decreased{{end}}

But I can’t figure out how to compare a value and a constant.
(I also tried using “0” instead of 0 - but that didn’t help).

2

I’m afraid this is a limitation of Go’s text/template, 0 needs to be 0.0 because the value is a floating point number.

3

That worked. Thanks !