From 55e763b4cd8cdb9252602f3abc22a6a45d57fe20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zolt=C3=A1n=20Bedi?= <zoltan.bedi@gmail.com>
Date: Wed, 7 Jul 2021 08:43:46 +0200
Subject: [PATCH] Prometheus: interpolate variable for step field (#36437)

* Prometheus: interpolate variable for step

* Add test for variable interpolation
---
 .../datasource/prometheus/datasource.test.ts    | 17 +++++++++++++++++
 .../plugins/datasource/prometheus/datasource.ts |  1 +
 2 files changed, 18 insertions(+)

diff --git a/public/app/plugins/datasource/prometheus/datasource.test.ts b/public/app/plugins/datasource/prometheus/datasource.test.ts
index 45de4c866c1..9e71fe63408 100644
--- a/public/app/plugins/datasource/prometheus/datasource.test.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.test.ts
@@ -553,6 +553,23 @@ describe('PrometheusDatasource', () => {
     });
   });
 
+  describe('interpolateVariablesInQueries', () => {
+    it('should call replace function 2 times', () => {
+      const query = {
+        expr: 'test{job="testjob"}',
+        format: 'time_series',
+        interval: '$Interval',
+        refId: 'A',
+      };
+      const interval = '10m';
+      templateSrvStub.replace.mockReturnValue(interval);
+
+      const queries = ds.interpolateVariablesInQueries([query], { Interval: { text: interval, value: interval } });
+      expect(templateSrvStub.replace).toBeCalledTimes(2);
+      expect(queries[0].interval).toBe(interval);
+    });
+  });
+
   describe('metricFindQuery', () => {
     beforeEach(() => {
       const query = 'query_result(topk(5,rate(http_request_duration_microseconds_count[$__interval])))';
diff --git a/public/app/plugins/datasource/prometheus/datasource.ts b/public/app/plugins/datasource/prometheus/datasource.ts
index db75f915398..0a5719b34fc 100644
--- a/public/app/plugins/datasource/prometheus/datasource.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.ts
@@ -735,6 +735,7 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
           ...query,
           datasource: this.name,
           expr: this.templateSrv.replace(query.expr, scopedVars, this.interpolateQueryExpr),
+          interval: this.templateSrv.replace(query.interval, scopedVars),
         };
         return expandedQuery;
       });