templating/selection does not work as expected.

[samuelbenhamou]

Hi,
I am not sure it is an issue or if the system is working as intended so take it as is.

I installed grafana /kairos/cassandra on different nodes. Played with it and so far so good; except for a small issue.
I am reporting metrics through collectd and added a template variable called host which I expected would help me filter my dashboard by host. Basically doing that in grafana :
$host tag_values(collectd.cpu.percent.active.value,host)

After I added this, the dashboard displayed a nice dropdown to help me select my hosts.

Now, coming to the graph itself, I expected to be able to specify this :
Metric collectd.cpu.percent.active.value
Tags host = ["$host"]
Group By tags: host

and it did not work as tracking down the plugin js I noticed that grafana is sending an array with only one index containing all expanded values.
Let's say I have 3 hosts, h1,h2,h3
it ended up with passing query.tags['host'][0]="{h1,h2,h3}" (datasource.js:340) which kairos could not evaluate. It should pass query.tags['host'][0]="h1",query.tags['host'][1]="h2"...

I just dirty patched it to make it work as I expected and now can select my hosts from the dropdown and get the selection working :

datasource.js:337

if (target.tags) {
      query.tags = angular.copy(target.tags);
      _.forOwn(query.tags, function(value, key) {
           query.tags[key] = _.map(value, function(tag) { return self.templateSrv.replace(tag); });
           var tmp=[];
           query.tags[key].forEach(function(subtag,index,qu_tag) {
                tmp=tmp.concat(subtag.replace(/{|}/g,'').split(","));
           });
           query.tags[key]=tmp;
      });
}

[jifwin]

+1

[jifwin]

In my opinion returning an object or array should be supported by Grafana's templateSrv, not the plugins itself. I've created a feature request in Grafana repository (grafana/grafana#5532)

[jifwin]

This should be fixed a while ago. Otherwise please reopen.