I have a Grafana dashboard that displays Prometheus metrics for two AWS instances. I have a dashboard variable defined that returns the instance IDs I am interested in. For an "All" option I am using ".*". I match the resulting instance ID in my panel queries with query{instance_id=~"$instance_id"}.The query involved in defining that variable is similar to this:
label_values(is_foo, instance_id)
That query works and gives me a nice way to select instances from a drop down menu on the dashboard.
Now, one instance returns 1 for is_foo and the other returns 0. What I am trying to achieve is a way to refer to the instances with names foo (for when is_foo is 1) and bar. Preferably there would be a drop down menu with names foo and bar and an "All" option, similar to what exists now. In the legends I would like the names to appear as well. Basically I am looking for a way to alias the instance IDs with pretty naming.
I have tried defining custom variables, for example foo_id with query_result(is_foo==1) and then assigning these to a custom map variable, foo : ${foo_id} but the foo_id variable will not expand. Is such a thing possible? Can custom variables be chained together?
