From f2208a9820c74f665d7706184c10fbc74f58df2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Giedrius=20Statkevi=C4=8Dius?=
 <giedrius.statkevicius@vinted.com>
Date: Fri, 3 May 2024 12:21:27 +0300
Subject: [PATCH] e2e/compact: add repro for issue #6775
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Adding a minimal test case for issue #6775 - reproduces the panic in the
compactor.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
---
 test/e2e/compact_test.go       | 77 ++++++++++++++++++++++++++++++++++
 test/e2e/e2ethanos/services.go | 30 +++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/test/e2e/compact_test.go b/test/e2e/compact_test.go
index daa2fa615e..94a3f344fe 100644
--- a/test/e2e/compact_test.go
+++ b/test/e2e/compact_test.go
@@ -924,3 +924,80 @@ func TestCompactorDownsampleIgnoresMarked(t *testing.T) {
 	testutil.NotOk(t, c.WaitSumMetricsWithOptions(e2emon.Greater(0), []string{"thanos_compact_downsample_total"}, e2emon.WaitMissingMetrics()))
 
 }
+
+// TestCompactorIssue6775 tests that the compactor does not crash when
+// compacting 5m downsampled blocks with some overlap.
+func TestCompactorIssue6775(t *testing.T) {
+	const minTime = 1710374400014
+	const maxTime = 1711584000000
+
+	logger := log.NewNopLogger()
+	e, err := e2e.NewDockerEnvironment("c-issue6775")
+	testutil.Ok(t, err)
+	t.Cleanup(e2ethanos.CleanScenario(t, e))
+
+	dir := filepath.Join(e.SharedDir(), "tmp")
+	testutil.Ok(t, os.MkdirAll(dir, os.ModePerm))
+
+	const bucket = "compact-test"
+	m := e2edb.NewMinio(e, "minio", bucket, e2edb.WithMinioTLS())
+	testutil.Ok(t, e2e.StartAndWaitReady(m))
+
+	bkt, err := s3.NewBucketWithConfig(logger,
+		e2ethanos.NewS3Config(bucket, m.Endpoint("http"), m.Dir()), "test-feed")
+	testutil.Ok(t, err)
+
+	baseBlockDesc := blockDesc{
+		series: []labels.Labels{
+			labels.FromStrings("z", "1", "b", "2"),
+			labels.FromStrings("z", "1", "b", "5"),
+		},
+		extLset: labels.FromStrings("case", "downsampled-block-with-overlap"),
+		mint:    minTime,
+		maxt:    maxTime,
+	}
+
+	for i := 0; i < 2; i++ {
+		rawBlockID, err := baseBlockDesc.Create(context.Background(), dir, 0, metadata.NoneFunc, 1200+i)
+		testutil.Ok(t, err)
+		testutil.Ok(t, objstore.UploadDir(context.Background(), logger, bkt, path.Join(dir, rawBlockID.String()), rawBlockID.String()))
+	}
+
+	// Downsample them first.
+	bds := e2ethanos.NewToolsBucketDownsample(e, "downsample", client.BucketConfig{
+		Type:   client.S3,
+		Config: e2ethanos.NewS3Config(bucket, m.InternalEndpoint("http"), m.InternalDir()),
+	})
+	testutil.Ok(t, bds.Start())
+
+	// NOTE(GiedriusS): can't use WaitSumMetrics here because the e2e library doesn't
+	// work well with histograms.
+	testutil.Ok(t, runutil.RetryWithLog(log.NewLogfmtLogger(os.Stderr), 1*time.Second, make(<-chan struct{}), func() (rerr error) {
+		resp, err := http.Get(fmt.Sprintf("http://%s/metrics", bds.Endpoint("http")))
+		if err != nil {
+			return fmt.Errorf("getting metrics: %w", err)
+		}
+		defer runutil.CloseWithErrCapture(&rerr, resp.Body, "close body")
+
+		b, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return fmt.Errorf("reading metrics: %w", err)
+		}
+
+		if !bytes.Contains(b, []byte(`thanos_compact_downsample_duration_seconds_count{resolution="0"} 2`)) {
+			return fmt.Errorf("failed to find the right downsampling metric")
+		}
+
+		return nil
+	}))
+
+	testutil.Ok(t, bds.Stop())
+
+	// Run the compactor.
+	c := e2ethanos.NewCompactorBuilder(e, "working").Init(client.BucketConfig{
+		Type:   client.S3,
+		Config: e2ethanos.NewS3Config(bucket, m.InternalEndpoint("http"), m.Dir()),
+	}, nil, "--compact.enable-vertical-compaction")
+	testutil.NotOk(t, e2e.StartAndWaitReady(c))
+	testutil.NotOk(t, c.WaitSumMetricsWithOptions(e2emon.Greater(0), []string{"thanos_compact_iterations_total"}, e2emon.WaitMissingMetrics()))
+}
diff --git a/test/e2e/e2ethanos/services.go b/test/e2e/e2ethanos/services.go
index 07141a4ac7..8d2174b6c1 100644
--- a/test/e2e/e2ethanos/services.go
+++ b/test/e2e/e2ethanos/services.go
@@ -1217,3 +1217,33 @@ func NewRedis(e e2e.Environment, name string) e2e.Runnable {
 		},
 	)
 }
+
+func NewToolsBucketDownsample(e e2e.Environment, name string, bucketConfig client.BucketConfig) *e2eobs.Observable {
+	f := e.Runnable(fmt.Sprintf("downsampler-%s", name)).
+		WithPorts(map[string]int{"http": 8080}).
+		Future()
+
+	bktConfigBytes, err := yaml.Marshal(bucketConfig)
+	if err != nil {
+		return &e2eobs.Observable{Runnable: e2e.NewFailedRunnable(name, errors.Wrapf(err, "generate store config file: %v", bucketConfig))}
+	}
+
+	args := []string{"bucket", "downsample"}
+
+	args = append(args, e2e.BuildArgs(map[string]string{
+		"--http-address":    ":8080",
+		"--log.level":       "debug",
+		"--objstore.config": string(bktConfigBytes),
+		"--data-dir":        f.InternalDir(),
+	})...)
+
+	return e2eobs.AsObservable(f.Init(
+		e2e.StartOptions{
+			Image:            DefaultImage(),
+			Command:          e2e.NewCommand("tools", args...),
+			User:             strconv.Itoa(os.Getuid()),
+			Readiness:        e2e.NewHTTPReadinessProbe("http", "/-/ready", 200, 200),
+			WaitReadyBackoff: &defaultBackoffConfig,
+		},
+	), "http")
+}