Check if there is request result #57 (#428)

server/package.json

@@ -38,7 +38,7 @@
     "es6-promise": "^4.2.4",
     "event-stream": "3.3.4",
     "file-loader": "^1.1.11",
-    "grafana-datasource-kit": "0.1.10",
+    "grafana-datasource-kit": "0.1.11",
     "jest": "^23.1.1",
     "koa": "^2.0.46",
     "koa-bodyparser": "^4.2.0",

server/src/controllers/analytics_controller.ts

@@ -9,7 +9,7 @@ import { AlertService } from '../services/alert_service';
 import { HASTIC_API_KEY, GRAFANA_URL } from '../config';
 import { DataPuller } from '../services/data_puller';
 
-import { queryByMetric } from 'grafana-datasource-kit';
+import { queryByMetric, ConnectionRefused } from 'grafana-datasource-kit';
 
 
 import * as _ from 'lodash';
@@ -126,14 +126,24 @@ async function query(analyticUnit: AnalyticUnit.AnalyticUnit, detector: Analytic
     panelUrl = analyticUnit.panelUrl;
   }
 
-  const queryResult = await queryByMetric(
-    analyticUnit.metric,
-    panelUrl,
-    range.from,
-    range.to,
-    HASTIC_API_KEY
-  );
-  const data = queryResult.values;
+  let data;
+
+  try {
+    const queryResult = await queryByMetric(
+      analyticUnit.metric,
+      panelUrl,
+      range.from,
+      range.to,
+      HASTIC_API_KEY
+    );
+    data = queryResult.values;
+  } catch(e) {
+    if(e instanceof ConnectionRefused) {
+      throw new Error(`Can't connect Grafana: ${e.message}, check GRAFANA_URL`);
+    }
+    throw e;
+  }
+
   if(data.length === 0) {
     throw new Error('Empty data to detect on');
   }

server/src/services/data_puller.ts

@@ -4,7 +4,7 @@ import * as AnalyticUnitCache from '../models/analytic_unit_cache_model';
 import { AnalyticsService } from './analytics_service';
 import { HASTIC_API_KEY, GRAFANA_URL } from '../config';
 
-import { queryByMetric } from 'grafana-datasource-kit';
+import { queryByMetric, ConnectionRefused } from 'grafana-datasource-kit';
 
 import * as _ from 'lodash';
 
@@ -15,6 +15,35 @@ const PULL_PERIOD_MS = 5000;
 
 export class DataPuller {
 
+  private _availableReporter = (positiveMsg: string|null, negativeMsg: string|null) => {
+    let reported = false;
+    return available => {
+      if(available && reported) {
+        reported = false;
+        if(positiveMsg) {
+          console.log(positiveMsg);
+        }
+      }
+
+      if(!available && !reported) {
+        reported = true;
+        if(negativeMsg) {
+          console.error(negativeMsg);
+        }
+      }
+    }
+  };
+
+  private _analyticReadyReporter = this._availableReporter(
+    'data puller: analytic ready, start pushing',
+    'data puller: analytic service not ready, return empty result'
+  );
+
+  private _grafanaConnectionRefusedReporter = this._availableReporter(
+    'data puller: connected to Grafana',
+    `data puller: can't connect to Grafana. Check GRAFANA_URL`
+  );
+
   private _unitTimes: { [analyticUnitId: string]: number } = {};
 
   constructor(private analyticsService: AnalyticsService) {};
@@ -126,8 +155,8 @@ export class DataPuller {
     AsyncIterableIterator<MetricDataChunk> {
 
     const getData = async () => {
+      this._analyticReadyReporter(this.analyticsService.ready);
       if(!this.analyticsService.ready) {
-        console.log(`data generator: analytic service not ready, return empty result while wait service`);
         return {
           columns: [],
           values: []
@@ -137,9 +166,21 @@ export class DataPuller {
       try {
         const time = this._unitTimes[analyticUnit.id]
         const now = Date.now();
-        return await this.pullData(analyticUnit, time, now);
+        const res = await this.pullData(analyticUnit, time, now);
+        this._grafanaConnectionRefusedReporter(true);
+        return res;
       } catch(err) {
-        throw new Error(`error while pulling data: ${err.message}`);
+
+        if(err instanceof ConnectionRefused) {
+          this._grafanaConnectionRefusedReporter(false);
+        } else {
+          console.error(`error while pulling data: ${err.message}`);
+        }
+
+        return {
+          columns: [],
+          values: []
+        };
       }
     }