IssueTracker

This will create a public issue which anybody can view and comment on.

I am unable to use templated legend for readability.We are using Cloud Monitoring to monitor our elasticsearch cluster.


Note that we have the same kind of issue for alerting. When using PromQL,
the message template cannot reference metric labels and display a dynamic
message.


Problem you have encountered:

Not being able to use PromQL legend templates

What you expected to happen:

Being able to use PromQL queries and customize the legend

Steps to reproduce:

We made some custom dashboards amd alerts with important metrics and data to watch. For example the number of shards per node. For some visualizations we need to perform more complex calculations on the
metrics, i.e. substract 2 of them, which is only possible to do with the
PromQL or MQL query language. On the builder graph, I've customized the legend using "Used/Max
${metric.labels.name}" syntax, but I can't do that operation on the PromQL
one. We tried using JSON editor but it does not work either.


We created a simple dashboard with the ID given in summary to show you the
behaviour, for example, if we need to monitor the max vs used java memory
on the same graph, with builder, we have a good readable dashboard but,
with exactly the same query translated to PromQL, we have a chart where all
the lines have the same name.

On the builder graph, I've customized the legend using "Used/Max
${metric.labels.name}" syntax, but I can't do that operation on the PromQL
one. We tried using JSON editor but it does not work either.

Other information (workarounds you have tried, documentation consulted, etc):

A workaround is to use PromQL's label_replace function to add one field with arbitrary text. And I have used this documentation [1].

[1] https://github.com/GoogleCloudPlatform/monitoring-dashboard-samples/blob/master/dev-docs/DASHBOARD_TIPS.md#legend-templates-for-non-mql-charts