Function testScrapeLoopAppendSampleLimit

scrape/scrape_test.go:3184–3252

(t *testing.T, appV2 bool)

}

func testScrapeLoopAppendSampleLimit(t *testing.T, appV2 bool) {
	appTest := teststorage.NewAppendable()
	sl, _ := newTestScrapeLoop(t, func(sl *scrapeLoop) {
		if appV2 {
			sl.appendableV2 = appendableV2Func(func(ctx context.Context) storage.AppenderV2 {
				// Chain appTest to verify what samples passed through.
				return &limitAppenderV2{AppenderV2: appTest.AppenderV2(ctx), limit: 1}
			})
		} else {
			sl.appendable = appendableFunc(func(ctx context.Context) storage.Appender {
				// Chain appTest to verify what samples passed through.
				return &limitAppender{Appender: appTest.Appender(ctx), limit: 1}
			})
		}

		sl.sampleMutator = func(l labels.Labels) labels.Labels {
			if l.Has("deleteme") {
				return labels.EmptyLabels()
			}
			return l
		}
		sl.sampleLimit = 1 // Same as limitAppender.limit
	})

	// Get the value of the Counter before performing append.
	beforeMetric := dto.Metric{}
	err := sl.metrics.targetScrapeSampleLimit.Write(&beforeMetric)
	require.NoError(t, err)

	beforeMetricValue := beforeMetric.GetCounter().GetValue()

	now := time.Now()
	app := sl.appender()
	total, added, seriesAdded, err := app.append([]byte("metric_a 1\nmetric_b 1\nmetric_c 1\n"), "text/plain", now)
	require.ErrorIs(t, err, errSampleLimit)
	require.NoError(t, app.Rollback())
	require.Equal(t, 3, total)
	require.Equal(t, 3, added)
	require.Equal(t, 1, seriesAdded)

	// Check that the Counter has been incremented a single time for the scrape,
	// not multiple times for each sample.
	metric := dto.Metric{}
	err = sl.metrics.targetScrapeSampleLimit.Write(&metric)
	require.NoError(t, err)

	v := metric.GetCounter().GetValue()
	change := v - beforeMetricValue
	require.Equal(t, 1.0, change, "Unexpected change of sample limit metric: %f", change)

	// And verify that we got the samples that fit under the limit.
	want := []sample{
		{
			L: labels.FromStrings(model.MetricNameLabel, "metric_a"),
			T: timestamp.FromTime(now),
			V: 1,
		},
	}