filtering tag values with curly braces not working

[sspieker]

Description

Some of our customers are pushing metrics with tags values containing curly braces. KairosDB does not forbid this, AFAIK.

The problem with this: filtering these tag values does not work in Grafana when using this datasource. The datapoints are shown alright though when they are not explicitely filtered.

When using the KairosDB UI, there's no problem whatsoever, even when filtering these tag values

Screenshots

Here are two screenshots illustrating the problem in a Grafana dashboard, followed by a screenshot of the KairosDB UI which shows that it is working there: