feat: add support --web.enable-otlp-receiver flag in the Prometheus/PrometheusAgent CRD (#7105)

* add otlp receiver

---------

Signed-off-by: dongjiang1989 <dongjiang1989@126.com>
Co-authored-by: Simon Pasquier <spasquie@redhat.com>

Documentation/api.md

@@ -1996,6 +1996,20 @@ For more information see <a href="https://prometheus.io/docs/prometheus/latest/q
 </tr>
 <tr>
 <td>
+<code>enableOTLPReceiver</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.</p>
+<p>Note that the OTLP receiver endpoint is automatically enabled if <code>.spec.otlpConfig</code> is defined.</p>
+<p>It requires Prometheus &gt;= v2.47.0.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>remoteWriteReceiverMessageVersions</code><br/>
 <em>
 <a href="#monitoring.coreos.com/v1.RemoteWriteMessageVersion">
@@ -6921,6 +6935,20 @@ For more information see <a href="https://prometheus.io/docs/prometheus/latest/q
 </tr>
 <tr>
 <td>
+<code>enableOTLPReceiver</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.</p>
+<p>Note that the OTLP receiver endpoint is automatically enabled if <code>.spec.otlpConfig</code> is defined.</p>
+<p>It requires Prometheus &gt;= v2.47.0.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>remoteWriteReceiverMessageVersions</code><br/>
 <em>
 <a href="#monitoring.coreos.com/v1.RemoteWriteMessageVersion">
@@ -11645,6 +11673,20 @@ For more information see <a href="https://prometheus.io/docs/prometheus/latest/q
 </tr>
 <tr>
 <td>
+<code>enableOTLPReceiver</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.</p>
+<p>Note that the OTLP receiver endpoint is automatically enabled if <code>.spec.otlpConfig</code> is defined.</p>
+<p>It requires Prometheus &gt;= v2.47.0.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>remoteWriteReceiverMessageVersions</code><br/>
 <em>
 <a href="#monitoring.coreos.com/v1.RemoteWriteMessageVersion">
@@ -18228,6 +18270,20 @@ For more information see <a href="https://prometheus.io/docs/prometheus/latest/q
 </tr>
 <tr>
 <td>
+<code>enableOTLPReceiver</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.</p>
+<p>Note that the OTLP receiver endpoint is automatically enabled if <code>.spec.otlpConfig</code> is defined.</p>
+<p>It requires Prometheus &gt;= v2.47.0.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>remoteWriteReceiverMessageVersions</code><br/>
 <em>
 <a href="#monitoring.coreos.com/v1.RemoteWriteMessageVersion">
@@ -26085,6 +26141,20 @@ For more information see <a href="https://prometheus.io/docs/prometheus/latest/q
 </tr>
 <tr>
 <td>
+<code>enableOTLPReceiver</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.</p>
+<p>Note that the OTLP receiver endpoint is automatically enabled if <code>.spec.otlpConfig</code> is defined.</p>
+<p>It requires Prometheus &gt;= v2.47.0.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>remoteWriteReceiverMessageVersions</code><br/>
 <em>
 <a href="#monitoring.coreos.com/v1.RemoteWriteMessageVersion">

bundle.yaml

@@ -23853,6 +23853,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote
@@ -35181,6 +35189,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote

example/prometheus-operator-crd-full/monitoring.coreos.com_prometheusagents.yaml

@@ -2910,6 +2910,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote

example/prometheus-operator-crd-full/monitoring.coreos.com_prometheuses.yaml

@@ -3605,6 +3605,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote

example/prometheus-operator-crd/monitoring.coreos.com_prometheusagents.yaml

@@ -2911,6 +2911,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote

example/prometheus-operator-crd/monitoring.coreos.com_prometheuses.yaml

@@ -3606,6 +3606,14 @@ spec:
                   type: string
                 type: array
                 x-kubernetes-list-type: set
+              enableOTLPReceiver:
+                description: |-
+                  Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+
+                  Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+
+                  It requires Prometheus >= v2.47.0.
+                type: boolean
               enableRemoteWriteReceiver:
                 description: |-
                   Enable Prometheus to be used as a receiver for the Prometheus remote

jsonnet/prometheus-operator/prometheusagents-crd.json

@@ -2528,6 +2528,10 @@
                     "type": "array",
                     "x-kubernetes-list-type": "set"
                   },
+                  "enableOTLPReceiver": {
+                    "description": "Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.\n\nNote that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.\n\nIt requires Prometheus >= v2.47.0.",
+                    "type": "boolean"
+                  },
                   "enableRemoteWriteReceiver": {
                     "description": "Enable Prometheus to be used as a receiver for the Prometheus remote\nwrite protocol.\n\nWARNING: This is not considered an efficient way of ingesting samples.\nUse it with caution for specific low-volume use cases.\nIt is not suitable for replacing the ingestion via scraping and turning\nPrometheus into a push-based metrics collection system.\nFor more information see https://prometheus.io/docs/prometheus/latest/querying/api/#remote-write-receiver\n\nIt requires Prometheus >= v2.33.0.",
                     "type": "boolean"

jsonnet/prometheus-operator/prometheuses-crd.json

@@ -3120,6 +3120,10 @@
                     "type": "array",
                     "x-kubernetes-list-type": "set"
                   },
+                  "enableOTLPReceiver": {
+                    "description": "Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.\n\nNote that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.\n\nIt requires Prometheus >= v2.47.0.",
+                    "type": "boolean"
+                  },
                   "enableRemoteWriteReceiver": {
                     "description": "Enable Prometheus to be used as a receiver for the Prometheus remote\nwrite protocol.\n\nWARNING: This is not considered an efficient way of ingesting samples.\nUse it with caution for specific low-volume use cases.\nIt is not suitable for replacing the ingestion via scraping and turning\nPrometheus into a push-based metrics collection system.\nFor more information see https://prometheus.io/docs/prometheus/latest/querying/api/#remote-write-receiver\n\nIt requires Prometheus >= v2.33.0.",
                     "type": "boolean"

pkg/apis/monitoring/v1/prometheus_types.go

@@ -318,6 +318,14 @@ type CommonPrometheusFields struct {
 	// It requires Prometheus >= v2.33.0.
 	EnableRemoteWriteReceiver bool `json:"enableRemoteWriteReceiver,omitempty"`
 
+	// Enable Prometheus to be used as a receiver for the OTLP Metrics protocol.
+	//
+	// Note that the OTLP receiver endpoint is automatically enabled if `.spec.otlpConfig` is defined.
+	//
+	// It requires Prometheus >= v2.47.0.
+	// +optional
+	EnableOTLPReceiver *bool `json:"enableOTLPReceiver,omitempty"`
+
 	// List of the protobuf message versions to accept when receiving the
 	// remote writes.
 	//

pkg/apis/monitoring/v1/zz_generated.deepcopy.go

@@ -752,6 +752,11 @@ func (in *CommonPrometheusFields) DeepCopyInto(out *CommonPrometheusFields) {
 			(*out)[key] = val
 		}
 	}
+	if in.EnableOTLPReceiver != nil {
+		in, out := &in.EnableOTLPReceiver, &out.EnableOTLPReceiver
+		*out = new(bool)
+		**out = **in
+	}
 	if in.RemoteWriteReceiverMessageVersions != nil {
 		in, out := &in.RemoteWriteReceiverMessageVersions, &out.RemoteWriteReceiverMessageVersions
 		*out = make([]RemoteWriteMessageVersion, len(*in))

pkg/client/applyconfiguration/monitoring/v1/commonprometheusfields.go

@@ -51,6 +51,7 @@ type CommonPrometheusFieldsApplyConfiguration struct {
 	ScrapeProtocols                      []monitoringv1.ScrapeProtocol                           `json:"scrapeProtocols,omitempty"`
 	ExternalLabels                       map[string]string                                       `json:"externalLabels,omitempty"`
 	EnableRemoteWriteReceiver            *bool                                                   `json:"enableRemoteWriteReceiver,omitempty"`
+	EnableOTLPReceiver                   *bool                                                   `json:"enableOTLPReceiver,omitempty"`
 	RemoteWriteReceiverMessageVersions   []monitoringv1.RemoteWriteMessageVersion                `json:"remoteWriteReceiverMessageVersions,omitempty"`
 	EnableFeatures                       []monitoringv1.EnableFeature                            `json:"enableFeatures,omitempty"`
 	ExternalURL                          *string                                                 `json:"externalUrl,omitempty"`
@@ -332,6 +333,14 @@ func (b *CommonPrometheusFieldsApplyConfiguration) WithEnableRemoteWriteReceiver
 	return b
 }
 
+// WithEnableOTLPReceiver sets the EnableOTLPReceiver field in the declarative configuration to the given value
+// and returns the receiver, so that objects can be built by chaining "With" function invocations.
+// If called multiple times, the EnableOTLPReceiver field is set to the value of the last call.
+func (b *CommonPrometheusFieldsApplyConfiguration) WithEnableOTLPReceiver(value bool) *CommonPrometheusFieldsApplyConfiguration {
+	b.EnableOTLPReceiver = &value
+	return b
+}
+
 // WithRemoteWriteReceiverMessageVersions adds the given value to the RemoteWriteReceiverMessageVersions field in the declarative configuration
 // and returns the receiver, so that objects can be build by chaining "With" function invocations.
 // If called multiple times, values provided by each call will be appended to the RemoteWriteReceiverMessageVersions field.

pkg/client/applyconfiguration/monitoring/v1/prometheusspec.go

@@ -267,6 +267,14 @@ func (b *PrometheusSpecApplyConfiguration) WithEnableRemoteWriteReceiver(value b
 	return b
 }
 
+// WithEnableOTLPReceiver sets the EnableOTLPReceiver field in the declarative configuration to the given value
+// and returns the receiver, so that objects can be built by chaining "With" function invocations.
+// If called multiple times, the EnableOTLPReceiver field is set to the value of the last call.
+func (b *PrometheusSpecApplyConfiguration) WithEnableOTLPReceiver(value bool) *PrometheusSpecApplyConfiguration {
+	b.EnableOTLPReceiver = &value
+	return b
+}
+
 // WithRemoteWriteReceiverMessageVersions adds the given value to the RemoteWriteReceiverMessageVersions field in the declarative configuration
 // and returns the receiver, so that objects can be build by chaining "With" function invocations.
 // If called multiple times, values provided by each call will be appended to the RemoteWriteReceiverMessageVersions field.

pkg/client/applyconfiguration/monitoring/v1alpha1/prometheusagentspec.go

@@ -255,6 +255,14 @@ func (b *PrometheusAgentSpecApplyConfiguration) WithEnableRemoteWriteReceiver(va
 	return b
 }
 
+// WithEnableOTLPReceiver sets the EnableOTLPReceiver field in the declarative configuration to the given value
+// and returns the receiver, so that objects can be built by chaining "With" function invocations.
+// If called multiple times, the EnableOTLPReceiver field is set to the value of the last call.
+func (b *PrometheusAgentSpecApplyConfiguration) WithEnableOTLPReceiver(value bool) *PrometheusAgentSpecApplyConfiguration {
+	b.EnableOTLPReceiver = &value
+	return b
+}
+
 // WithRemoteWriteReceiverMessageVersions adds the given value to the RemoteWriteReceiverMessageVersions field in the declarative configuration
 // and returns the receiver, so that objects can be build by chaining "With" function invocations.
 // If called multiple times, values provided by each call will be appended to the RemoteWriteReceiverMessageVersions field.

pkg/prometheus/common_test.go

@@ -15,6 +15,7 @@
 package prometheus
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -159,3 +160,125 @@ func TestBuildCommonPrometheusArgsWithRemoteWriteMessageV2(t *testing.T) {
 		})
 	}
 }
+
+func TestBuildCommonPrometheusArgsWithOTLPReceiver(t *testing.T) {
+	for _, tc := range []struct {
+		version                    string
+		enableOTLPReceiver         *bool
+		expectedOTLPReceiverFlag   bool
+		OTLPConfig                 *monitoringv1.OTLPConfig
+		expectedOTLPFeatureEnabled bool
+	}{
+		// OTLP receiver not supported.
+		{
+			version:                    "2.46.0",
+			enableOTLPReceiver:         ptr.To(true),
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// OTLP receiver supported starting with v2.47.0.
+		{
+			version:                    "2.47.0",
+			enableOTLPReceiver:         ptr.To(true),
+			expectedOTLPFeatureEnabled: true,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// OTLP receiver supported but not enabled.
+		{
+			version:                    "2.47.0",
+			enableOTLPReceiver:         ptr.To(false),
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// OTLP receiver config supported but verison not support
+		{
+			version:            "2.46.0",
+			enableOTLPReceiver: ptr.To(false),
+			OTLPConfig: &monitoringv1.OTLPConfig{
+				PromoteResourceAttributes: []string{"aa", "bb"},
+			},
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// OTLP receiver config supported
+		{
+			version:            "2.55.0",
+			enableOTLPReceiver: nil,
+			OTLPConfig: &monitoringv1.OTLPConfig{
+				PromoteResourceAttributes: []string{"aa", "bb"},
+			},
+			expectedOTLPFeatureEnabled: true,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// OTLP receiver config supported with verison 3.x
+		{
+			version:            "3.0.0",
+			enableOTLPReceiver: nil,
+			OTLPConfig: &monitoringv1.OTLPConfig{
+				PromoteResourceAttributes: []string{"aa", "bb"},
+			},
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   true,
+		},
+		// Test higher version from which enable-feature available.
+		{
+			version:                    "2.54.0",
+			enableOTLPReceiver:         ptr.To(true),
+			expectedOTLPFeatureEnabled: true,
+			expectedOTLPReceiverFlag:   false,
+		},
+		// Test higher version from which web.enable-otlp-receiver arg available.
+		{
+			version:                    "3.0.0",
+			enableOTLPReceiver:         ptr.To(true),
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   true,
+		},
+		// Test higher version but not enabled.
+		{
+			version:                    "3.0.0",
+			enableOTLPReceiver:         ptr.To(false),
+			expectedOTLPFeatureEnabled: false,
+			expectedOTLPReceiverFlag:   false,
+		},
+	} {
+		t.Run("", func(t *testing.T) {
+			p := &monitoringv1.Prometheus{
+				Spec: monitoringv1.PrometheusSpec{
+					CommonPrometheusFields: monitoringv1.CommonPrometheusFields{
+						Version:            tc.version,
+						EnableOTLPReceiver: tc.enableOTLPReceiver,
+						OTLP:               tc.OTLPConfig,
+					},
+				},
+			}
+
+			cg, err := NewConfigGenerator(NewLogger(), p)
+			require.NoError(t, err)
+
+			args := cg.BuildCommonPrometheusArgs()
+
+			var (
+				argsEnabled    bool
+				featureEnabled bool
+			)
+			for _, arg := range args {
+				switch arg.Name {
+				case "web.enable-otlp-receiver":
+					argsEnabled = true
+				case "enable-feature":
+					feats := strings.Split(arg.Value, ",")
+					for _, feat := range feats {
+						if feat == "otlp-write-receiver" {
+							featureEnabled = true
+							break
+						}
+					}
+				}
+			}
+
+			require.Equal(t, tc.expectedOTLPReceiverFlag, argsEnabled)
+			require.Equal(t, tc.expectedOTLPFeatureEnabled, featureEnabled)
+		})
+	}
+}

pkg/prometheus/promcfg.go

@@ -1009,6 +1009,15 @@ func (cg *ConfigGenerator) BuildCommonPrometheusArgs() []monitoringv1.Argument {
 		}
 	}
 
+	// Turn on the OTLP receiver endpoint automatically if/when the OTLP config isn't empty.
+	if (cpf.EnableOTLPReceiver != nil && *cpf.EnableOTLPReceiver) || (cpf.EnableOTLPReceiver == nil && cpf.OTLP != nil) {
+		if cg.version.Major >= 3 {
+			promArgs = cg.AppendCommandlineArgument(promArgs, monitoringv1.Argument{Name: "web.enable-otlp-receiver"})
+		} else {
+			promArgs = cg.WithMinimumVersion("2.47.0").AppendCommandlineArgument(promArgs, monitoringv1.Argument{Name: "enable-feature", Value: "otlp-write-receiver"})
+		}
+	}
+
 	if len(cpf.EnableFeatures) > 0 {
 		efs := make([]string, len(cpf.EnableFeatures))
 		for i := range cpf.EnableFeatures {