support specifying tag_values("<tag>") as graphite template query

public/app/features/templating/partials/editor.html

@@ -16,12 +16,12 @@
 					Add variable
 				</a>
 				<div class="grafana-info-box">
-					<h5>What does variables do?</h5>
-					<p>Variables enables more interactive and dynamic dashboards. Instead of hard-coding things like server or sensor names
+					<h5>What do variables do?</h5>
+					<p>Variables enable more interactive and dynamic dashboards. Instead of hard-coding things like server or sensor names
 					in your metric queries you can use variables in their place. Variables are shown as dropdown select boxes at the top of
 					the dashboard. These dropdowns make it easy to change the data being displayed in your dashboard.
 
-					Checkout the
+					Check out the
 					<a class="external-link" href="http://docs.grafana.org/reference/templating/" target="_blank">
 						Templating documentation
 					</a> for more information.
@@ -93,7 +93,7 @@
 			</div>
 
 			<div class="gf-form" ng-show="ctrl.form.name.$error.pattern">
-				<span class="gf-form-label gf-form-label--error">Template names cannot begin with '__' that's reserved for Grafanas global variables</span>
+				<span class="gf-form-label gf-form-label--error">Template names cannot begin with '__', that's reserved for Grafana's global variables</span>
 			</div>
 
 			<div class="gf-form-inline">

public/app/plugins/datasource/graphite/datasource.ts

@@ -202,6 +202,35 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
     let options = optionalOptions || {};
     let interpolatedQuery = templateSrv.replace(query);
 
+    // special handling for tag_values(<tag>[,<expression>]*), this is used for template variables
+    let matches = interpolatedQuery.match(/^tag_values\(([^,]+)((, *[^,]+)*)\)$/);
+    if (matches) {
+      const expressions = [];
+      const exprRegex = /, *([^,]+)/g;
+      let match;
+      while ((match = exprRegex.exec(matches[2])) !== null) {
+        expressions.push(match[1]);
+      }
+      options.limit = 10000;
+      return this.getTagValuesAutoComplete(expressions, matches[1], undefined, options);
+    }
+
+    // special handling for tags(<expression>[,<expression>]*), this is used for template variables
+    matches = interpolatedQuery.match(/^tags\(([^,]*)((, *[^,]+)*)\)$/);
+    if (matches) {
+      const expressions = [];
+      if (matches[1]) {
+        expressions.push(matches[1]);
+        const exprRegex = /, *([^,]+)/g;
+        let match;
+        while ((match = exprRegex.exec(matches[2])) !== null) {
+          expressions.push(match[1]);
+        }
+      }
+      options.limit = 10000;
+      return this.getTagsAutoComplete(expressions, undefined, options);
+    }
+
     let httpOptions: any = {
       method: 'GET',
       url: '/metrics/find',
@@ -212,7 +241,7 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
       requestId: options.requestId,
     };
 
-    if (options && options.range) {
+    if (options.range) {
       httpOptions.params.from = this.translateTime(options.range.from, false);
       httpOptions.params.until = this.translateTime(options.range.to, true);
     }
@@ -237,7 +266,7 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
       requestId: options.requestId,
     };
 
-    if (options && options.range) {
+    if (options.range) {
       httpOptions.params.from = this.translateTime(options.range.from, false);
       httpOptions.params.until = this.translateTime(options.range.to, true);
     }
@@ -262,7 +291,7 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
       requestId: options.requestId,
     };
 
-    if (options && options.range) {
+    if (options.range) {
       httpOptions.params.from = this.translateTime(options.range.from, false);
       httpOptions.params.until = this.translateTime(options.range.to, true);
     }
@@ -281,18 +310,29 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
     });
   };
 
-  this.getTagsAutoComplete = (expression, tagPrefix) => {
+  this.getTagsAutoComplete = (expressions, tagPrefix, optionalOptions) => {
+    let options = optionalOptions || {};
+
     let httpOptions: any = {
       method: 'GET',
       url: '/tags/autoComplete/tags',
       params: {
-        expr: expression,
+        expr: expressions,
       },
+      // for cancellations
+      requestId: options.requestId,
     };
 
     if (tagPrefix) {
       httpOptions.params.tagPrefix = tagPrefix;
     }
+    if (options.limit) {
+      httpOptions.params.limit = options.limit;
+    }
+    if (options.range) {
+      httpOptions.params.from = this.translateTime(options.range.from, false);
+      httpOptions.params.until = this.translateTime(options.range.to, true);
+    }
 
     return this.doGraphiteRequest(httpOptions).then(results => {
       if (results.data) {
@@ -305,19 +345,30 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
     });
   };
 
-  this.getTagValuesAutoComplete = (expression, tag, valuePrefix) => {
+  this.getTagValuesAutoComplete = (expressions, tag, valuePrefix, limit, optionalOptions) => {
+    let options = optionalOptions || {};
+
     let httpOptions: any = {
       method: 'GET',
       url: '/tags/autoComplete/values',
       params: {
-        expr: expression,
+        expr: expressions,
         tag: tag,
       },
+      // for cancellations
+      requestId: options.requestId,
     };
 
     if (valuePrefix) {
       httpOptions.params.valuePrefix = valuePrefix;
     }
+    if (options.limit) {
+      httpOptions.params.limit = options.limit;
+    }
+    if (options.range) {
+      httpOptions.params.from = this.translateTime(options.range.from, false);
+      httpOptions.params.until = this.translateTime(options.range.to, true);
+    }
 
     return this.doGraphiteRequest(httpOptions).then(results => {
       if (results.data) {
@@ -330,10 +381,14 @@ export function GraphiteDatasource(instanceSettings, $q, backendSrv, templateSrv
     });
   };
 
-  this.getVersion = function() {
+  this.getVersion = function(optionalOptions) {
+    let options = optionalOptions || {};
+
     let httpOptions = {
       method: 'GET',
       url: '/version/_', // Prevent last / trimming
+      // for cancellations
+      requestId: options.requestId,
     };
 
     return this.doGraphiteRequest(httpOptions)