Prometheus
Limit query to specific hours
We can use the
hour()
function to limit a query to a specific time range. I’ve used this to define
alerts with different thresholds at different times of the day.
http_requests_total{job="foo"} and on() hour() >= 0 < 12
Note the use of and on() instead of simply and. vector1 and vector2
results in a vector consisting of the elements of vector1 for which there are
elements in vector2 with exactly matching label sets. However because
hour() is a vector with no labels, simply doing and hour() >= 0 will not
return any results. Instead we add the on() operator to ignore all labels
when performing the join.