Move health check to the backend (#2120)

This PR moves the health check to backend only leaving in the frontend
the functionality to test the dbconnector datasource.

Leaving the `dbconnector.testDataSource` should be fine since the
datasource types we allow for db connection with Zabbix already are
backend datasources, and so their health requests would go through the
backend.

Verified:
Clicking test and seeing a `health` request go out.

IMPORTANT: While testing this in the UI, I found a bug with the config
editor - whenever a change is made in the UI and tested, the changes
don't take effect (i.e. disabling trends, keeps `trends` set to `true`,
enabling db connection keep `dbConnectionEnabled` set to `false` and so
on.). Created a separate
[issue](https://github.com/orgs/grafana/projects/457/views/40?pane=issue&itemId=3627315751&issue=grafana%7Coss-big-tent-squad%7C132)
to fix this

Fixes https://github.com/grafana/oss-big-tent-squad/issues/124
Fixes https://github.com/grafana/grafana-zabbix/issues/2004

src/datasource/datasource.ts

@@ -21,6 +21,7 @@ import {
   toDataQueryResponse,
   getDataSourceSrv,
   HealthCheckError,
+  DataSourceWithBackend,
 } from '@grafana/runtime';
 import {
   DataFrame,
@@ -55,6 +56,7 @@ export class ZabbixDatasource extends DataSourceApi<ZabbixMetricsQuery, ZabbixDS
   dbConnectionRetentionPolicy: string;
   enableDebugLog: boolean;
   datasourceId: number;
+  instanceSettings: DataSourceInstanceSettings<ZabbixDSOptions>;
   zabbix: Zabbix;
 
   replaceTemplateVars: (target: any, scopedVars?: any) => any;
@@ -62,6 +64,7 @@ export class ZabbixDatasource extends DataSourceApi<ZabbixMetricsQuery, ZabbixDS
   constructor(instanceSettings: DataSourceInstanceSettings<ZabbixDSOptions>) {
     super(instanceSettings);
 
+    this.instanceSettings = instanceSettings;
     this.enableDebugLog = config.buildInfo.env === 'development';
 
     this.annotations = {
@@ -767,17 +770,20 @@ export class ZabbixDatasource extends DataSourceApi<ZabbixMetricsQuery, ZabbixDS
    * Test connection to Zabbix API and external history DB.
    */
   async testDatasource() {
+    const backendDS = new DataSourceWithBackend(this.instanceSettings);
     try {
-      const { zabbixVersion, dbConnectorStatus } = await this.zabbix.testDataSource();
-      let message = `Zabbix API version: ${zabbixVersion}`;
-      if (dbConnectorStatus) {
-        message += `, DB connector type: ${dbConnectorStatus.dsType}`;
-      }
-      return {
-        status: 'success',
-        title: 'Success',
-        message: message,
-      };
+      const testResult = await backendDS.testDatasource();
+      return this.zabbix.testDataSource().then((dbConnectorStatus) => {
+        let message = testResult.message;
+        if (dbConnectorStatus) {
+          message += `, DB connector type: ${dbConnectorStatus.dsType}`;
+        }
+        return {
+          status: testResult.status,
+          message: message,
+          title: testResult.status,
+        };
+      });
     } catch (error: any) {
       if (error instanceof ZabbixAPIError) {
         return Promise.reject({

src/datasource/zabbix/zabbix.ts

@@ -208,32 +208,21 @@ export class Zabbix implements ZabbixConnector {
    * ```
    */
   testDataSource() {
-    let zabbixVersion;
     let dbConnectorStatus;
-    return this.getVersion()
-      .then((version) => {
-        zabbixVersion = version;
-        return this.getAllGroups();
-      })
-      .then(() => {
-        if (this.enableDirectDBConnection) {
-          return this.dbConnector.testDataSource();
-        } else {
-          return Promise.resolve();
-        }
-      })
-      .catch((error) => {
-        return Promise.reject(error);
-      })
-      .then((testResult) => {
+
+    if (this.enableDirectDBConnection) {
+      return this.dbConnector.testDataSource().then((testResult) => {
         if (testResult) {
           dbConnectorStatus = {
             dsType: this.dbConnector.datasourceTypeName || this.dbConnector.datasourceTypeId,
             dsName: this.dbConnector.datasourceName,
           };
+          return dbConnectorStatus;
         }
-        return { zabbixVersion, dbConnectorStatus };
       });
+    } else {
+      return Promise.resolve();
+    }
   }
 
   async getVersion() {