fixed applying remoteWrite.label for pushed metrics (#4247) (#4824)

vmagent: properly add extra labels before sending data to remote storage

labels from `remoteWrite.label` are now added to sent metrics just before they
 are pushed to `remoteWrite.url` after all relabelings, including stream aggregation relabelings (#4247)

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247

Signed-off-by: Alexander Marshalov <_@marshalov.org>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
(cherry picked from commit a27c2f3773)

app/vmagent/remotewrite/relabel.go

@@ -87,8 +87,8 @@ func initLabelsGlobal() {
 	}
 }
 
-func (rctx *relabelCtx) applyRelabeling(tss []prompbmarshal.TimeSeries, extraLabels []prompbmarshal.Label, pcs *promrelabel.ParsedConfigs) []prompbmarshal.TimeSeries {
+func (rctx *relabelCtx) applyRelabeling(tss []prompbmarshal.TimeSeries, pcs *promrelabel.ParsedConfigs) []prompbmarshal.TimeSeries {
-	if len(extraLabels) == 0 && pcs.Len() == 0 && !*usePromCompatibleNaming {
+	if pcs.Len() == 0 && !*usePromCompatibleNaming {
 		// Nothing to change.
 		return tss
 	}
@@ -98,16 +98,6 @@ func (rctx *relabelCtx) applyRelabeling(tss []prompbmarshal.TimeSeries, extraLab
 		ts := &tss[i]
 		labelsLen := len(labels)
 		labels = append(labels, ts.Labels...)
-		// extraLabels must be added before applying relabeling according to https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write
-		for j := range extraLabels {
-			extraLabel := &extraLabels[j]
-			tmp := promrelabel.GetLabelByName(labels[labelsLen:], extraLabel.Name)
-			if tmp != nil {
-				tmp.Value = extraLabel.Value
-			} else {
-				labels = append(labels, *extraLabel)
-			}
-		}
 		if *usePromCompatibleNaming {
 			// Replace unsupported Prometheus chars in label names and metric names with underscores.
 			tmpLabels := labels[labelsLen:]
@@ -135,6 +125,38 @@ func (rctx *relabelCtx) applyRelabeling(tss []prompbmarshal.TimeSeries, extraLab
 	return tssDst
 }
 
+func (rctx *relabelCtx) appendExtraLabels(tss []prompbmarshal.TimeSeries, extraLabels []prompbmarshal.Label) []prompbmarshal.TimeSeries {
+	if len(extraLabels) == 0 {
+		return tss
+	}
+	tssDst := tss[:0]
+	labels := rctx.labels[:0]
+	for i := range tss {
+		ts := &tss[i]
+		labelsLen := len(labels)
+		labels = append(labels, ts.Labels...)
+		for j := range extraLabels {
+			extraLabel := extraLabels[j]
+			if *usePromCompatibleNaming {
+				extraLabel.Name = promrelabel.SanitizeLabelName(extraLabel.Name)
+			}
+			tmp := promrelabel.GetLabelByName(labels[labelsLen:], extraLabel.Name)
+			if tmp != nil {
+				tmp.Value = extraLabel.Value
+			} else {
+				labels = append(labels, extraLabel)
+			}
+		}
+		labels = promrelabel.FinalizeLabels(labels[:labelsLen], labels[labelsLen:])
+		tssDst = append(tssDst, prompbmarshal.TimeSeries{
+			Labels:  labels[labelsLen:],
+			Samples: ts.Samples,
+		})
+	}
+	rctx.labels = labels
+	return tssDst
+}
+
 type relabelCtx struct {
 	// pool for labels, which are used during the relabeling.
 	labels []prompbmarshal.Label

app/vmagent/remotewrite/relabel_test.go

@@ -10,18 +10,16 @@ import (
 )
 
 func TestApplyRelabeling(t *testing.T) {
-	f := func(extraLabels []prompbmarshal.Label, pcs *promrelabel.ParsedConfigs, sTss, sExpTss string) {
+	f := func(pcs *promrelabel.ParsedConfigs, sTss, sExpTss string) {
 		rctx := &relabelCtx{}
 		tss, expTss := parseSeries(sTss), parseSeries(sExpTss)
-		gotTss := rctx.applyRelabeling(tss, extraLabels, pcs)
+		gotTss := rctx.applyRelabeling(tss, pcs)
 		if !reflect.DeepEqual(gotTss, expTss) {
 			t.Fatalf("expected to have: \n%v;\ngot: \n%v", expTss, gotTss)
 		}
 	}
 
-	f(nil, nil, "up", "up")
+	f(nil, "up", "up")
-	f([]prompbmarshal.Label{{Name: "foo", Value: "bar"}}, nil, "up", `up{foo="bar"}`)
-	f([]prompbmarshal.Label{{Name: "foo", Value: "bar"}}, nil, `up{foo="baz"}`, `up{foo="bar"}`)
 
 	pcs, err := promrelabel.ParseRelabelConfigsData([]byte(`
 - target_label: "foo"
@@ -32,11 +30,32 @@ func TestApplyRelabeling(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unexpected error: %s", err)
 	}
-	f(nil, pcs, `up{foo="baz", env="prod"}`, `up{foo="aaa"}`)
+	f(pcs, `up{foo="baz", env="prod"}`, `up{foo="aaa"}`)
 
 	oldVal := *usePromCompatibleNaming
 	*usePromCompatibleNaming = true
-	f(nil, nil, `foo.bar`, `foo_bar`)
+	f(nil, `foo.bar`, `foo_bar`)
+	*usePromCompatibleNaming = oldVal
+}
+
+func TestAppendExtraLabels(t *testing.T) {
+	f := func(extraLabels []prompbmarshal.Label, sTss, sExpTss string) {
+		rctx := &relabelCtx{}
+		tss, expTss := parseSeries(sTss), parseSeries(sExpTss)
+		gotTss := rctx.appendExtraLabels(tss, extraLabels)
+		if !reflect.DeepEqual(gotTss, expTss) {
+			t.Fatalf("expected to have: \n%v;\ngot: \n%v", expTss, gotTss)
+		}
+	}
+
+	f(nil, "up", "up")
+	f([]prompbmarshal.Label{{Name: "foo", Value: "bar"}}, "up", `up{foo="bar"}`)
+	f([]prompbmarshal.Label{{Name: "foo", Value: "bar"}}, `up{foo="baz"}`, `up{foo="bar"}`)
+	f([]prompbmarshal.Label{{Name: "baz", Value: "qux"}}, `up{foo="baz"}`, `up{foo="baz",baz="qux"}`)
+
+	oldVal := *usePromCompatibleNaming
+	*usePromCompatibleNaming = true
+	f([]prompbmarshal.Label{{Name: "foo.bar", Value: "baz"}}, "up", `up{foo_bar="baz"}`)
 	*usePromCompatibleNaming = oldVal
 }
 

app/vmagent/remotewrite/remotewrite.go

@@ -386,7 +386,7 @@ func Push(at *auth.Token, wr *prompbmarshal.WriteRequest) {
 		}
 		if rctx != nil {
 			rowsCountBeforeRelabel := getRowsCount(tssBlock)
-			tssBlock = rctx.applyRelabeling(tssBlock, labelsGlobal, pcsGlobal)
+			tssBlock = rctx.applyRelabeling(tssBlock, pcsGlobal)
 			rowsCountAfterRelabel := getRowsCount(tssBlock)
 			rowsDroppedByGlobalRelabel.Add(rowsCountBeforeRelabel - rowsCountAfterRelabel)
 		}
@@ -668,7 +668,7 @@ func (rwctx *remoteWriteCtx) Push(tss []prompbmarshal.TimeSeries) {
 		v = tssPool.Get().(*[]prompbmarshal.TimeSeries)
 		tss = append(*v, tss...)
 		rowsCountBeforeRelabel := getRowsCount(tss)
-		tss = rctx.applyRelabeling(tss, nil, pcs)
+		tss = rctx.applyRelabeling(tss, pcs)
 		rowsCountAfterRelabel := getRowsCount(tss)
 		rwctx.rowsDroppedByRelabel.Add(rowsCountBeforeRelabel - rowsCountAfterRelabel)
 	}
@@ -719,6 +719,11 @@ func dropAggregatedSeries(src []prompbmarshal.TimeSeries, matchIdxs []byte, drop
 }
 
 func (rwctx *remoteWriteCtx) pushInternal(tss []prompbmarshal.TimeSeries) {
+	if len(labelsGlobal) > 0 {
+		rctx := getRelabelCtx()
+		tss = rctx.appendExtraLabels(tss, labelsGlobal)
+		putRelabelCtx(rctx)
+	}
 	pss := rwctx.pss
 	idx := atomic.AddUint64(&rwctx.pssNextIdx, 1) % uint64(len(pss))
 	pss[idx].Push(tss)

docs/CHANGELOG.md

@@ -26,6 +26,7 @@ The following `tip` changes can be tested by building VictoriaMetrics components
 
 * FEATURE: [vmbackup](https://docs.victoriametrics.com/vmbackup.html): add support for server-side copy of existing backups. See [these docs](https://docs.victoriametrics.com/vmbackup.html#server-side-copy-of-the-existing-backup) for details.
 
+* BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): according to [the docs](https://docs.victoriametrics.com/vmagent.html#adding-labels-to-metrics) labels from `-remoteWrite.label` cmd-line flag are now added to the sent metrics just before they are pushed to the `-remoteWrite.url` (after all relabeling, including stream aggregation relabeling). In addition, it allows adding labels for identifying vmagent instances when using streaming aggregation in vmagents [cluster mode](https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets). See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247) and [these docs](https://docs.victoriametrics.com/stream-aggregation.html#cluster-mode) for more details.
 * BUGFIX: remove `DEBUG` logging when parsing `if` filters inside [relabeling rules](https://docs.victoriametrics.com/vmagent.html#relabeling-enhancements) and when parsing `match` filters inside [stream aggregation rules](https://docs.victoriametrics.com/stream-aggregation.html).
 * BUGFIX: properly replace `:` chars in label names with `_` when `-usePromCompatibleNaming` command-line flag is passed to `vmagent`, `vminsert` or single-node VictoriaMetrics. This addresses [this comment](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3113#issuecomment-1275077071).
 * BUGFIX: [Official Grafana dashboards for VictoriaMetrics](https://grafana.com/orgs/victoriametrics): fix display of ingested rows rate for `Samples ingested/s` and `Samples rate` panels for vmagent's dasbhoard. Previously, not all ingested protocols were accounted in these panels. An extra panel `Rows rate` was added to `Ingestion` section to display the split for rows ingested rate by protocol.

docs/stream-aggregation.md

@@ -1,7 +1,7 @@
 ---
 sort: 98
 weight: 98
-title: streaming aggregation
+title: Streaming aggregation
 menu:
   docs:
     parent: "victoriametrics"
@@ -10,7 +10,7 @@ aliases:
 - /stream-aggregation.html
 ---
 
-# streaming aggregation
+# Streaming aggregation
 
 [vmagent](https://docs.victoriametrics.com/vmagent.html) and [single-node VictoriaMetrics](https://docs.victoriametrics.com/Single-server-VictoriaMetrics.html)
 can aggregate incoming [samples](https://docs.victoriametrics.com/keyConcepts.html#raw-samples) in streaming mode by time and by labels before data is written to remote storage.
@@ -673,3 +673,13 @@ support the following approaches for hot reloading stream aggregation configs fr
   ```
 
 * By sending HTTP request to `/-/reload` endpoint (e.g. `http://vmagent:8429/-/reload` or `http://victoria-metrics:8428/-/reload).
+
+## Cluster mode
+
+If you use [vmagent in cluster mode](https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets) for streaming aggregation
+(with `-promscrape.cluster.*` parameters or with `VMAgent.spec.shardCount > 1` for [vmoperator](https://docs.victoriametrics.com/operator))
+then be careful when aggregating metrics via `by`, `without` or modifying via`*_relabel_configs` parameters, as incorrect usage may result in duplicates and data collision. For example, if more than one vmagent calculates `increase` for metric `http_requests_total` with `by: [path]` directive, then the resulting time series written to the remote database will be indistinguishable, as there is no way to tell to which `instance` the aggregation belongs. The proper fix would be to add a unique aggregation dimension: `by: [instance, path]`. With this change, aggregates between `instances` won't collide.
+
+If adding a new aggregation dimension isn't feasible (due to cardinality reduction purposes), then it is worth at least differentiating by which vmagent the aggregation was performed. You can do it with `remoteWrite.label` [parameter in vmagent](https://docs.victoriametrics.com/vmagent.html#adding-labels-to-metrics).
+For example, for running in docker or k8s you can use `remoteWrite.label` with `POD_NAME` or `HOSTNAME` environment variable: `remoteWrite.label='vmagent=%{HOSTNAME}'`.
+See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247#issue-1692894073) for details.