Merge pull request #15563 from GiedriusS/fix_setting_field

scrape: fix nil panic after scrape loop reload

scrape/scrape.go

@@ -361,6 +361,7 @@ func (sp *scrapePool) restartLoops(reuseCache bool) {
 				bodySizeLimit:        bodySizeLimit,
 				acceptHeader:         acceptHeader(sp.config.ScrapeProtocols, validationScheme),
 				acceptEncodingHeader: acceptEncodingHeader(enableCompression),
+				metrics:              sp.metrics,
 			}
 			newLoop = sp.newLoop(scrapeLoopOptions{
 				target:                   t,

scrape/scrape_test.go

@@ -4831,3 +4831,44 @@ func newScrapableServer(scrapeText string) (s *httptest.Server, scrapedTwice cha
 		}
 	})), scrapedTwice
 }
+
+// Regression test for the panic fixed in https://github.com/prometheus/prometheus/pull/15523.
+func TestScrapePoolScrapeAfterReload(t *testing.T) {
+	h := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			w.Write([]byte{0x42, 0x42})
+		},
+	))
+	t.Cleanup(h.Close)
+
+	cfg := &config.ScrapeConfig{
+		BodySizeLimit:     1,
+		JobName:           "test",
+		Scheme:            "http",
+		ScrapeInterval:    model.Duration(100 * time.Millisecond),
+		ScrapeTimeout:     model.Duration(100 * time.Millisecond),
+		EnableCompression: false,
+		ServiceDiscoveryConfigs: discovery.Configs{
+			&discovery.StaticConfig{
+				{
+					Targets: []model.LabelSet{{model.AddressLabel: model.LabelValue(h.URL)}},
+				},
+			},
+		},
+	}
+
+	p, err := newScrapePool(cfg, &nopAppendable{}, 0, nil, nil, &Options{}, newTestScrapeMetrics(t))
+	require.NoError(t, err)
+	t.Cleanup(p.stop)
+
+	p.Sync([]*targetgroup.Group{
+		{
+			Targets: []model.LabelSet{{model.AddressLabel: model.LabelValue(strings.TrimPrefix(h.URL, "http://"))}},
+			Source:  "test",
+		},
+	})
+
+	require.NoError(t, p.reload(cfg))
+
+	<-time.After(1 * time.Second)
+}