Prometheus: Fix min step variable interpolation (#27505)

* Add missing dependency to lockfile

* Prometheus: Fix min step variable interpolation

public/app/plugins/datasource/prometheus/datasource.test.ts

@@ -1640,12 +1640,12 @@ describe('PrometheusDatasource', () => {
     it('should be 4 times the scrape interval if min step set to 1m and interval is 15s', () => {
       // For a 5m graph, $__interval is 15s
       ds.createQuery({ ...target, interval: '1m' }, { interval: '15s' } as any, 0, 300);
-      expect((templateSrv.replace as any).mock.calls[1][1]['__rate_interval'].value).toBe('240s');
+      expect((templateSrv.replace as any).mock.calls[2][1]['__rate_interval'].value).toBe('240s');
     });
     it('should be interval + scrape interval if min step set to 1m and interval is 5m', () => {
       // For a 7d graph, $__interval is 5m
       ds.createQuery({ ...target, interval: '1m' }, { interval: '5m' } as any, 0, 10080);
-      expect((templateSrv.replace as any).mock.calls[1][1]['__rate_interval'].value).toBe('360s');
+      expect((templateSrv.replace as any).mock.calls[2][1]['__rate_interval'].value).toBe('360s');
     });
     it('should be interval + scrape interval if resolution is set to 1/2 and interval is 10m', () => {
       // For a 7d graph, $__interval is 10m
@@ -1657,6 +1657,12 @@ describe('PrometheusDatasource', () => {
       ds.createQuery({ ...target, intervalFactor: 2 }, { interval: '15s' } as any, 0, 300);
       expect((templateSrv.replace as any).mock.calls[1][1]['__rate_interval'].value).toBe('60s');
     });
+    it('should interpolate min step if set', () => {
+      templateSrv.replace = jest.fn(() => '15s');
+      ds.createQuery({ ...target, interval: '$int' }, { interval: '15s' } as any, 0, 300);
+      expect((templateSrv.replace as any).mock.calls).toHaveLength(3);
+      templateSrv.replace = jest.fn((a: string) => a);
+    });
   });
 });
 

public/app/plugins/datasource/prometheus/datasource.ts

@@ -351,7 +351,11 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
       templateSrv.replace(target.interval || options.interval, options.scopedVars)
     );
     // Scrape interval as specified for the query ("Min step") or otherwise taken from the datasource.
-    const scrapeInterval = rangeUtil.intervalToSeconds(target.interval || this.interval);
+    // Min step field can have template variables in it, make sure to replace it.
+    const scrapeInterval = target.interval
+      ? rangeUtil.intervalToSeconds(templateSrv.replace(target.interval, options.scopedVars))
+      : rangeUtil.intervalToSeconds(this.interval);
+
     const intervalFactor = target.intervalFactor || 1;
     // Adjust the interval to take into account any specified minimum and interval factor plus Prometheus limits
     const adjustedInterval = this.adjustInterval(interval, minInterval, range, intervalFactor);

yarn.lock

@@ -19633,6 +19633,11 @@ pako@~1.0.5:
   resolved "https://registry.yarnpkg.com/pako/-/pako-1.0.10.tgz#4328badb5086a426aa90f541977d4955da5c9732"
   integrity sha512-0DTvPVU3ed8+HNXOu5Bs+o//Mbdj9VNQMUOe9oKCwh8l0GNwpTDMKCWbRjgtD291AWnkAgkqA/LOnQS8AmS1tw==
 
+papaparse@4.6.3:
+  version "4.6.3"
+  resolved "https://registry.yarnpkg.com/papaparse/-/papaparse-4.6.3.tgz#742e5eaaa97fa6c7e1358d2934d8f18f44aee781"
+  integrity sha512-LRq7BrHC2kHPBYSD50aKuw/B/dGcg29omyJbKWY3KsYUZU69RKwaBHu13jGmCYBtOc4odsLCrFyk6imfyNubJQ==
+
 papaparse@5.3.0:
   version "5.3.0"
   resolved "https://registry.yarnpkg.com/papaparse/-/papaparse-5.3.0.tgz#ab1702feb96e79ab4309652f36db9536563ad05a"