[receiver/prometheusremotewrite] Align job label mapping with prometheusreceiver

.chloggen/pr_52626.yaml

@@ -0,0 +1,4 @@
+change_type: enhancement
+component: receiver/prometheus_remote_write
+note: "Adds an alpha feature gate `receiver.prometheus_remote_write.disableJobSplit` to map the `job` label directly to `service.name` without splitting, aligning with the `prometheusreceiver`."
+issues: [52626]

receiver/prometheusremotewritereceiver/README.md

@@ -145,6 +145,36 @@ This approach has some limitations, for example:
 
 The receiver reports every eviction in the `otelcol_receiver_prometheusremotewrite_resource_cache_evictions` internal metric. A counter that keeps growing means the cache is smaller than the number of job/instance pairs sent to the receiver.
 
+### Job and Instance Label Mapping
+
+For each `job` and `instance` pair:
+- `instance` (when non-empty) is mapped to the `service.instance.id` resource attribute.
+- By default, if `job` contains a single `/` (`<namespace>/<name>`), it is split into `service.namespace` and `service.name`; otherwise the full `job` value is mapped to `service.name`.
+- When the `receiver.prometheus_remote_write.disableJobSplit` feature gate is enabled (`--feature-gates=receiver.prometheus_remote_write.disableJobSplit`), the receiver maps the entire `job` value directly to `service.name` without splitting on `/`, matching `prometheusreceiver`. Because a valid `service.name` may itself contain `/`, the receiver cannot distinguish a `/` within `service.name` from a concatenated `<service.namespace>/<service.name>` value.
+- Any attributes present on `target_info` series for the same `job`/`instance` pair take precedence and overwrite resource attributes derived from `job` and `instance`.
+
+#### Migrating to `receiver.prometheus_remote_write.disableJobSplit`
+
+If you rely on `service.namespace` being populated when `receiver.prometheus_remote_write.disableJobSplit` is enabled (or once it becomes the default):
+
+1. **OTLP -> Prometheus -> Remote Write -> OTLP round-trip via `target_info`**:
+   In the [OTLP-to-Prometheus specification](https://opentelemetry.io/docs/specs/otel/compatibility/prometheus_and_openmetrics/#resource-attributes-1), `service.namespace` and `service.name` are concatenated into `job="<service.namespace>/<service.name>"`. For round-trip preservation of `service.namespace` and `service.name` without splitting `job`:
+   - Configure the OTLP-to-Prometheus sender to include identifying resource attributes on `target_info` (e.g., `keep_identifying_resource_attributes: true` in `prometheusexporter` / `prometheusremotewriteexporter`, or `keep_identifying_attributes` in Prometheus OTLP ingestion) so `service.namespace` and `service.name` are emitted as labels on `target_info` (for Prometheus native OTLP ingestion, see also [prometheus/prometheus#20086](https://github.com/prometheus/prometheus/pull/20086)).
+   - Disable dot-to-underscore label translation on the sender/Prometheus side (preserve UTF-8 dots in label names, e.g. `translation_strategy: NoUTF8EscapingWithSuffixes`) so `target_info` carries `service.namespace` and `service.name` rather than `service_namespace` and `service_name`.
+
+2. **Splitting `job` via the `transform` processor (when `target_info` is not used)**:
+   If your sender encodes `<service.namespace>/<service.name>` in `job` without emitting `service.namespace` on `target_info`, you can preserve the `<namespace>/<name>` split downstream using the [`transform` processor](../../processor/transformprocessor/README.md):
+
+   ```yaml
+   processors:
+     transform:
+       metric_statements:
+         - context: resource
+           statements:
+             - set(attributes["service.namespace"], Split(attributes["service.name"], "/")[0]) where IsMatch(attributes["service.name"], "^[^/]+/[^/]+$") and attributes["service.namespace"] == nil
+             - set(attributes["service.name"], Split(attributes["service.name"], "/")[1]) where IsMatch(attributes["service.name"], "^[^/]+/[^/]+$")
+   ```
+
 ## Internal Telemetry
 
-See [documentation.md](./documentation.md) for the list of internal metrics emitted by this receiver.
+See [documentation.md](./documentation.md) for the list of internal metrics and feature gates for this receiver.

receiver/prometheusremotewritereceiver/documentation.md

@@ -27,3 +27,13 @@ Number of job/instance entries evicted from the resource metrics cache because i
 | Unit | Metric Type | Value Type | Monotonic | Stability |
 | ---- | ----------- | ---------- | --------- | --------- |
 | {entries} | Sum | Int | true | Development |
+
+## Feature Gates
+
+This component has the following feature gates:
+
+| Feature Gate | Stage | Description | From Version | To Version | Reference |
+| ------------ | ----- | ----------- | ------------ | ---------- | --------- |
+| `receiver.prometheus_remote_write.disableJobSplit` | alpha | When enabled, the prometheusremotewritereceiver will disable the splitting of the job label by '/' to derive service.namespace and service.name, instead mapping the entire job string to service.name. | v0.165.0 | N/A | [Link](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/52626) |
+
+For more information about feature gates, see the [Feature Gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md) documentation.

receiver/prometheusremotewritereceiver/go.mod

@@ -22,6 +22,7 @@ require (
 	go.opentelemetry.io/collector/consumer v1.71.0
 	go.opentelemetry.io/collector/consumer/consumererror v0.165.0
 	go.opentelemetry.io/collector/consumer/consumertest v0.165.0
+	go.opentelemetry.io/collector/featuregate v1.71.0
 	go.opentelemetry.io/collector/pdata v1.71.0
 	go.opentelemetry.io/collector/receiver v1.71.0
 	go.opentelemetry.io/collector/receiver/receiverhelper v0.165.0
@@ -115,7 +116,6 @@ require (
 	go.opentelemetry.io/collector/consumer/xconsumer v0.165.0 // indirect
 	go.opentelemetry.io/collector/extension/extensionauth v1.71.0 // indirect
 	go.opentelemetry.io/collector/extension/extensionmiddleware v0.165.0 // indirect
-	go.opentelemetry.io/collector/featuregate v1.71.0 // indirect
 	go.opentelemetry.io/collector/internal/componentalias v0.165.0 // indirect
 	go.opentelemetry.io/collector/pdata/pprofile v0.165.0 // indirect
 	go.opentelemetry.io/collector/pdata/xpdata v0.165.0 // indirect

receiver/prometheusremotewritereceiver/metadata.yaml

@@ -48,3 +48,11 @@ tests:
       top:
         # See https://github.com/census-instrumentation/opencensus-go/issues/1191 for more information.
         - "go.opencensus.io/stats/view.(*worker).start"
+
+feature_gates:
+  - id: receiver.prometheus_remote_write.disableJobSplit
+    stage: alpha
+    description: >-
+      When enabled, the prometheusremotewritereceiver will disable the splitting of the job label by '/' to derive service.namespace and service.name, instead mapping the entire job string to service.name.
+    from_version: v0.165.0
+    reference_url: https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/52626

receiver/prometheusremotewritereceiver/receiver.go

@@ -814,11 +814,13 @@ func parseJobAndInstance(dest pcommon.Map, job, instance string) {
 		dest.PutStr("service.instance.id", instance)
 	}
 	if job != "" {
-		parts := strings.Split(job, "/")
-		if len(parts) == 2 {
-			dest.PutStr("service.namespace", parts[0])
-			dest.PutStr("service.name", parts[1])
-			return
+		if !metadata.ReceiverPrometheusRemoteWriteDisableJobSplitFeatureGate.IsEnabled() {
+			parts := strings.Split(job, "/")
+			if len(parts) == 2 {
+				dest.PutStr("service.namespace", parts[0])
+				dest.PutStr("service.name", parts[1])
+				return
+			}
 		}
 		dest.PutStr("service.name", job)
 	}

receiver/prometheusremotewritereceiver/receiver_feature_gate_test.go

@@ -0,0 +1,196 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package prometheusremotewritereceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/prometheusremotewritereceiver"
+
+import (
+	"testing"
+
+	writev2 "github.com/prometheus/prometheus/prompb/io/prometheus/write/v2"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/featuregate"
+	"go.opentelemetry.io/collector/pdata/pcommon"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/prometheusremotewritereceiver/internal/metadata"
+)
+
+func setDisableJobSplitFeatureGate(t *testing.T, enabled bool) {
+	t.Helper()
+	t.Cleanup(func() {
+		assert.NoError(t, featuregate.GlobalRegistry().Set(metadata.ReceiverPrometheusRemoteWriteDisableJobSplitFeatureGate.ID(), false))
+	})
+	require.NoError(t, featuregate.GlobalRegistry().Set(metadata.ReceiverPrometheusRemoteWriteDisableJobSplitFeatureGate.ID(), enabled))
+}
+
+func TestParseJobAndInstanceFeatureGate(t *testing.T) {
+	tests := []struct {
+		name     string
+		gate     bool
+		job      string
+		instance string
+		expected map[string]any
+	}{
+		{
+			name:     "gate=false splits namespace/service",
+			gate:     false,
+			job:      "namespace/service",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.namespace":   "namespace",
+				"service.name":        "service",
+			},
+		},
+		{
+			name:     "gate=true preserves namespace/service in service.name",
+			gate:     true,
+			job:      "namespace/service",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.name":        "namespace/service",
+			},
+		},
+		{
+			name:     "gate=false my-job",
+			gate:     false,
+			job:      "my-job",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.name":        "my-job",
+			},
+		},
+		{
+			name:     "gate=true my-job",
+			gate:     true,
+			job:      "my-job",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.name":        "my-job",
+			},
+		},
+		{
+			name:     "gate=false multiple slashes a/b/c",
+			gate:     false,
+			job:      "a/b/c",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.name":        "a/b/c",
+			},
+		},
+		{
+			name:     "gate=true multiple slashes a/b/c",
+			gate:     true,
+			job:      "a/b/c",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+				"service.name":        "a/b/c",
+			},
+		},
+		{
+			name:     "gate=false empty job",
+			gate:     false,
+			job:      "",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+			},
+		},
+		{
+			name:     "gate=true empty job",
+			gate:     true,
+			job:      "",
+			instance: "instance-1",
+			expected: map[string]any{
+				"service.instance.id": "instance-1",
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			setDisableJobSplitFeatureGate(t, tc.gate)
+
+			dest := pcommon.NewMap()
+			parseJobAndInstance(dest, tc.job, tc.instance)
+			assert.Equal(t, tc.expected, dest.AsRaw())
+		})
+	}
+}
+
+func TestTranslateV2DisableJobSplitFeatureGate(t *testing.T) {
+	setDisableJobSplitFeatureGate(t, true)
+
+	t.Run("without target_info keeps namespace/service in service.name", func(t *testing.T) {
+		prwReceiver := setupMetricsReceiver(t)
+		req := &writev2.Request{
+			Symbols: []string{
+				"",
+				"__name__", "test_metric", // 1, 2
+				"instance", "host-1", // 3, 4
+				"job", "namespace/service", // 5, 6
+			},
+			Timeseries: []writev2.TimeSeries{
+				{
+					Metadata:   writev2.Metadata{Type: writev2.Metadata_METRIC_TYPE_GAUGE},
+					LabelsRefs: []uint32{1, 2, 3, 4, 5, 6},
+					Samples:    []writev2.Sample{{Value: 1, Timestamp: 1000}},
+				},
+			},
+		}
+
+		m, _, err := prwReceiver.translateV2(t.Context(), req)
+		require.NoError(t, err)
+		require.Equal(t, 1, m.ResourceMetrics().Len())
+
+		resAttrs := m.ResourceMetrics().At(0).Resource().Attributes()
+		assert.Equal(t, map[string]any{
+			"service.name":        "namespace/service",
+			"service.instance.id": "host-1",
+		}, resAttrs.AsRaw())
+		_, hasNamespace := resAttrs.Get("service.namespace")
+		assert.False(t, hasNamespace)
+	})
+
+	t.Run("target_info service.name and service.namespace take precedence", func(t *testing.T) {
+		prwReceiver := setupMetricsReceiver(t)
+		req := &writev2.Request{
+			Symbols: []string{
+				"",
+				"__name__", "target_info", "test_metric", // 1, 2, 3
+				"instance", "host-1", // 4, 5
+				"job", "namespace/service", // 6, 7
+				"service.name", "explicit-service", // 8, 9
+				"service.namespace", "explicit-namespace", // 10, 11
+			},
+			Timeseries: []writev2.TimeSeries{
+				{
+					Metadata:   writev2.Metadata{Type: writev2.Metadata_METRIC_TYPE_GAUGE},
+					LabelsRefs: []uint32{1, 2, 4, 5, 6, 7, 8, 9, 10, 11},
+					Samples:    []writev2.Sample{{Value: 1, Timestamp: 1000}},
+				},
+				{
+					Metadata:   writev2.Metadata{Type: writev2.Metadata_METRIC_TYPE_GAUGE},
+					LabelsRefs: []uint32{1, 3, 4, 5, 6, 7},
+					Samples:    []writev2.Sample{{Value: 42, Timestamp: 1000}},
+				},
+			},
+		}
+
+		m, _, err := prwReceiver.translateV2(t.Context(), req)
+		require.NoError(t, err)
+		require.Equal(t, 1, m.ResourceMetrics().Len())
+
+		resAttrs := m.ResourceMetrics().At(0).Resource().Attributes()
+		assert.Equal(t, map[string]any{
+			"service.name":        "explicit-service",
+			"service.namespace":   "explicit-namespace",
+			"service.instance.id": "host-1",
+		}, resAttrs.AsRaw())
+	})
+}