api: allow tracing sampleRate smaller than 1% (envoyproxy#5096)

* api: allow tracing sampleRate smaller than 1% Signed-off-by: zirain <[email protected]> Signed-off-by: EshaanAgg <[email protected]>
EshaanAgg · Jan 22, 2025 · 9bda954 · 9bda954
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diff --git a/api/v1alpha1/tracing_types.go b/api/v1alpha1/tracing_types.go
@@ -5,15 +5,32 @@
 
 package v1alpha1
 
+import gwapiv1 "sigs.k8s.io/gateway-api/apis/v1"
+
+// ProxyTracing defines the tracing configuration for a proxy.
+// +kubebuilder:validation:XValidation:message="only one of SamplingRate or SamplingFraction can be specified",rule="!(has(self.samplingRate) && has(self.samplingFraction))"
 type ProxyTracing struct {
 	// SamplingRate controls the rate at which traffic will be
 	// selected for tracing if no prior sampling decision has been made.
 	// Defaults to 100, valid values [0-100]. 100 indicates 100% sampling.
+	//
+	// Only one of SamplingRate or SamplingFraction may be specified.
+	// If neither field is specified, 1% of requests will be sampled.
+	//
 	// +kubebuilder:validation:Minimum=0
 	// +kubebuilder:validation:Maximum=100
 	// +kubebuilder:default=100
 	// +optional
 	SamplingRate *uint32 `json:"samplingRate,omitempty"`
+	// SamplingFraction represents the fraction of requests that should be
+	// selected for tracing if no prior sampling decision has been made.
+	//
+	// Only one of SamplingRate or SamplingFraction may be specified.
+	// If neither field is specified, 1% of requests will be sampled.
+	//
+	// +notImplementedHide
+	// +optional
+	SamplingFraction *gwapiv1.Fraction `json:"samplingFraction,omitempty"`
 	// CustomTags defines the custom tags to add to each span.
 	// If provider is kubernetes, pod name and namespace are added by default.
 	CustomTags map[string]CustomTag `json:"customTags,omitempty"`

diff --git a/api/v1alpha1/zz_generated.deepcopy.go b/api/v1alpha1/zz_generated.deepcopy.go
diff --git a/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml b/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml
@@ -14437,19 +14437,49 @@ spec:
                         - message: BackendRefs only supports Core group.
                           rule: 'has(self.backendRefs) ? (self.backendRefs.all(f,
                             f.group == "")) : true'
+                      samplingFraction:
+                        description: |-
+                          SamplingFraction represents the fraction of requests that should be
+                          selected for tracing if no prior sampling decision has been made.
+
+                          Only one of SamplingRate or SamplingFraction may be specified.
+                          If neither field is specified, 1% of requests will be sampled.
+                        properties:
+                          denominator:
+                            default: 100
+                            format: int32
+                            minimum: 1
+                            type: integer
+                          numerator:
+                            format: int32
+                            minimum: 0
+                            type: integer
+                        required:
+                        - numerator
+                        type: object
+                        x-kubernetes-validations:
+                        - message: numerator must be less than or equal to denominator
+                          rule: self.numerator <= self.denominator
                       samplingRate:
                         default: 100
                         description: |-
                           SamplingRate controls the rate at which traffic will be
                           selected for tracing if no prior sampling decision has been made.
                           Defaults to 100, valid values [0-100]. 100 indicates 100% sampling.
+
+                          Only one of SamplingRate or SamplingFraction may be specified.
+                          If neither field is specified, 1% of requests will be sampled.
                         format: int32
                         maximum: 100
                         minimum: 0
                         type: integer
                     required:
                     - provider
                     type: object
+                    x-kubernetes-validations:
+                    - message: only one of SamplingRate or SamplingFraction can be
+                        specified
+                      rule: '!(has(self.samplingRate) && has(self.samplingFraction))'
                 type: object
             type: object
           status:

diff --git a/site/content/en/latest/api/extension_types.md b/site/content/en/latest/api/extension_types.md
@@ -3419,14 +3419,14 @@ _Appears in:_
 
 
 
-
+ProxyTracing defines the tracing configuration for a proxy.
 
 _Appears in:_
 - [ProxyTelemetry](#proxytelemetry)
 
 | Field | Type | Required | Default | Description |
 | ---   | ---  | ---      | ---     | ---         |
-| `samplingRate` | _integer_ |  false  | 100 | SamplingRate controls the rate at which traffic will be<br />selected for tracing if no prior sampling decision has been made.<br />Defaults to 100, valid values [0-100]. 100 indicates 100% sampling. |
+| `samplingRate` | _integer_ |  false  | 100 | SamplingRate controls the rate at which traffic will be<br />selected for tracing if no prior sampling decision has been made.<br />Defaults to 100, valid values [0-100]. 100 indicates 100% sampling.<br /><br />Only one of SamplingRate or SamplingFraction may be specified.<br />If neither field is specified, 1% of requests will be sampled. |
 | `customTags` | _object (keys:string, values:[CustomTag](#customtag))_ |  true  |  | CustomTags defines the custom tags to add to each span.<br />If provider is kubernetes, pod name and namespace are added by default. |
 | `provider` | _[TracingProvider](#tracingprovider)_ |  true  |  | Provider defines the tracing provider. |
 

diff --git a/site/content/zh/latest/api/extension_types.md b/site/content/zh/latest/api/extension_types.md
@@ -3419,14 +3419,14 @@ _Appears in:_
 
 
 
-
+ProxyTracing defines the tracing configuration for a proxy.
 
 _Appears in:_
 - [ProxyTelemetry](#proxytelemetry)
 
 | Field | Type | Required | Default | Description |
 | ---   | ---  | ---      | ---     | ---         |
-| `samplingRate` | _integer_ |  false  | 100 | SamplingRate controls the rate at which traffic will be<br />selected for tracing if no prior sampling decision has been made.<br />Defaults to 100, valid values [0-100]. 100 indicates 100% sampling. |
+| `samplingRate` | _integer_ |  false  | 100 | SamplingRate controls the rate at which traffic will be<br />selected for tracing if no prior sampling decision has been made.<br />Defaults to 100, valid values [0-100]. 100 indicates 100% sampling.<br /><br />Only one of SamplingRate or SamplingFraction may be specified.<br />If neither field is specified, 1% of requests will be sampled. |
 | `customTags` | _object (keys:string, values:[CustomTag](#customtag))_ |  true  |  | CustomTags defines the custom tags to add to each span.<br />If provider is kubernetes, pod name and namespace are added by default. |
 | `provider` | _[TracingProvider](#tracingprovider)_ |  true  |  | Provider defines the tracing provider. |
 

diff --git a/test/cel-validation/envoyproxy_test.go b/test/cel-validation/envoyproxy_test.go
@@ -19,6 +19,7 @@ import (
 	gwapiv1 "sigs.k8s.io/gateway-api/apis/v1"
 
 	egv1a1 "github.com/envoyproxy/gateway/api/v1alpha1"
+	"github.com/envoyproxy/gateway/internal/gatewayapi"
 )
 
 func TestEnvoyProxyProvider(t *testing.T) {
@@ -1404,6 +1405,38 @@ func TestEnvoyProxyProvider(t *testing.T) {
 				"provided bootstrap patch doesn't match the configured patch type",
 			},
 		},
+		{
+			desc: "cannot set samplingRate and samplingFraction at the same time",
+			mutate: func(envoy *egv1a1.EnvoyProxy) {
+				envoy.Spec = egv1a1.EnvoyProxySpec{
+					Telemetry: &egv1a1.ProxyTelemetry{
+						Tracing: &egv1a1.ProxyTracing{
+							SamplingRate:     ptr.To[uint32](1),
+							SamplingFraction: &gwapiv1.Fraction{Numerator: 1, Denominator: ptr.To[int32](1000)},
+							Provider: egv1a1.TracingProvider{
+								BackendCluster: egv1a1.BackendCluster{
+									BackendRefs: []egv1a1.BackendRef{
+										{
+											BackendObjectReference: gwapiv1.BackendObjectReference{
+												Namespace: gatewayapi.NamespacePtr("ns-2"),
+												Name:      "test-backend",
+												Kind:      gatewayapi.KindPtr("Backend"),
+												Group:     gatewayapi.GroupPtr(egv1a1.GroupName),
+											},
+										},
+									},
+								},
+								Type:   egv1a1.TracingProviderTypeZipkin,
+								Zipkin: &egv1a1.ZipkinTracingProvider{},
+							},
+						},
+					},
+				}
+			},
+			wantErrors: []string{
+				"only one of SamplingRate or SamplingFraction can be specified",
+			},
+		},
 	}
 
 	for _, tc := range cases {