skip backend request if extended statistics is invalid. (#12495)

* check extended statistics pattern

* check extended statistics pattern

* Revert "check extended statistics pattern"

This reverts commit 52c7b1a972636d5f5729e64ae5e00e6fae329257.

* add test

* fix test

public/app/plugins/datasource/cloudwatch/datasource.ts

@@ -39,6 +39,14 @@ export default class CloudWatchDatasource {
       item.dimensions = this.convertDimensionFormat(item.dimensions, options.scopedVars);
       item.period = String(this.getPeriod(item, options)); // use string format for period in graph query, and alerting
 
+      // valid ExtendedStatistics is like p90.00, check the pattern
+      let hasInvalidStatistics = item.statistics.some(s => {
+        return s.indexOf('p') === 0 && !/p\d{2}\.\d{2}/.test(s);
+      });
+      if (hasInvalidStatistics) {
+        throw { message: 'Invalid extended statistics' };
+      }
+
       return _.extend(
         {
           refId: item.refId,

public/app/plugins/datasource/cloudwatch/specs/datasource.jest.ts

@@ -121,6 +121,26 @@ describe('CloudWatchDatasource', function() {
       });
     });
 
+    it('should cancel query for invalid extended statistics', function () {
+      var query = {
+        range: { from: 'now-1h', to: 'now' },
+        rangeRaw: { from: 1483228800, to: 1483232400 },
+        targets: [
+          {
+            region: 'us-east-1',
+            namespace: 'AWS/EC2',
+            metricName: 'CPUUtilization',
+            dimensions: {
+              InstanceId: 'i-12345678',
+            },
+            statistics: ['pNN.NN'],
+            period: '60s',
+          },
+        ],
+      };
+      expect(ctx.ds.query.bind(ctx.ds, query)).toThrow(/Invalid extended statistics/);
+    });
+
     it('should return series list', function(done) {
       ctx.ds.query(query).then(function(result) {
         expect(result.data[0].target).toBe(response.results.A.series[0].name);