docs: describes new variable formatting syntax

Fixes #11388
Ref #11141

docs/sources/reference/templating.md

@@ -36,6 +36,27 @@ interpolation the variable value might be **escaped** in order to conform to the
 For example, a variable used in a regex expression in an InfluxDB or Prometheus query will be regex escaped. Read the data source specific
 For example, a variable used in a regex expression in an InfluxDB or Prometheus query will be regex escaped. Read the data source specific
 documentation article for details on value escaping during interpolation.
 documentation article for details on value escaping during interpolation.
 
 
+### Advanced Formatting Options
+
+In Grafana 5.0, an additional option was added to control the formatting of the interpolation.
+
+Syntax: `${var_name:option}`
+
+Filter Option | Example | Raw | Interpolated | Description
+------------ | ------------- | ------------- | -------------  | -------------
+`glob` | ${servers:glob} |  `'test1', 'test2'` | `{test1,test2}` | (Default) Formats multi-value variable into a glob (for Graphite queries)
+`regex` | ${servers:regex} | `'test.', 'test2'` |  `(test\\.|test2)` | Formats multi-value variable into a regex string
+`pipe` | ${servers:pipe} | `'test.', 'test2'` |  `test.|test2` | Formats multi-value variable into a pipe-separated string
+`csv`| ${servers:csv} |  `'test1', 'test2'` | `test1,test2` | Formats multi-value variable as a comma-separated string (requires Grafana 5.1)
+`distributed`| ${servers:distributed} | `'test1', 'test2'` | `test1,servers=test2` | Formats multi-value variable in custom format for OpenTSDB.
+`lucene`| ${servers:lucene} | `'test', 'test2'` | `("test" OR "test2")` | Formats multi-value variable as a lucene expression.
+
+Test the formatting options on the [Grafana Play site](http://play.grafana.org/d/cJtIfcWiz/template-variable-formatting-options?orgId=1).
+
+If any invalid formatting option is specified, then `glob` is the default/fallback option.
+
+An alternative syntax is `[[var_name:option]]`.
+
 ### Variable options
 ### Variable options
 
 
 A variable is presented as a dropdown select box at the top of the dashboard. It has a current value and a set of **options**. The **options**
 A variable is presented as a dropdown select box at the top of the dashboard. It has a current value and a set of **options**. The **options**