add health query to support explore mode

port of grafana#80

Author: BrandonArp

dist/core/datasource.d.ts

@@ -18,6 +18,7 @@ export declare class KairosDBDatasource {
     private templatingUtils;
     constructor(instanceSettings: any, $q: any, backendSrv: any, templateSrv: any);
     initialize(): void;
+    testDatasource(): any;
     query(options: any): any;
     getMetricTags(metricNameTemplate: any, filters?: {}): any;
     metricFindQuery(query: string): Promise<{

dist/core/datasource.js

@@ -51,6 +51,11 @@ export class KairosDBDatasource {
         this.metricNamesStore.initialize().then(() => this.initialized = true, () => this.initializationError = true);
     }
 
+    public testDatasource() {
+        return this.executeRequest(this.getRequestBuilder().buildHealthStatusQuery())
+            .then((response) => response.status);
+    }
+
     public query(options) {
         const enabledTargets = _.cloneDeep(options.targets.filter((target) => !target.hide));
         const convertedTargets = _.map(enabledTargets, (target) => {

dist/core/datasource.js.map

@@ -7,6 +7,7 @@ export declare class KairosDBQueryBuilder {
     private templatingUtils;
     private samplingParameterConverter;
     constructor(withCredentials: boolean, url: string, apiPath: string, templateSrv: any, scopedVars: any);
+    buildHealthStatusQuery(): any;
     buildMetricNameQuery(): any;
     buildMetricTagsQuery(metricName: string, filters?: {}): any;
     buildDatapointsQuery(targets: any, options: any): any;