Support sample rate and global sampling configuration for Datadog in ConfigMap

internal/ingress/controller/config/config.go

@@ -552,6 +552,17 @@ type Configuration struct {
 	// Default: nginx.handle
 	DatadogOperationNameOverride string `json:"datadog-operation-name-override"`
 
+	// DatadogPrioritySampling specifies to use client-side sampling
+	// If true disables client-side sampling (thus ignoring sample_rate) and enables distributed
+	// priority sampling, where traces are sampled based on a combination of user-assigned
+	// Default: true
+	DatadogPrioritySampling bool `json:"datadog-priority-sampling"`
+
+	// DatadogSampleRate specifies sample rate for any traces created.
+	// This is effective only when datadog-priority-sampling is false
+	// Default: 1.0
+	DatadogSampleRate float32 `json:"datadog-sample-rate"`
+
 	// MainSnippet adds custom configuration to the main section of the nginx configuration
 	MainSnippet string `json:"main-snippet"`
 
@@ -767,6 +778,8 @@ func NewDefault() Configuration {
 		DatadogServiceName:           "nginx",
 		DatadogCollectorPort:         8126,
 		DatadogOperationNameOverride: "nginx.handle",
+		DatadogSampleRate:            1.0,
+		DatadogPrioritySampling:      true,
 		LimitReqStatusCode:           503,
 		LimitConnStatusCode:          503,
 		SyslogPort:                   514,

internal/ingress/controller/nginx.go

@@ -1075,7 +1075,9 @@ const datadogTmpl = `{
   "service": "{{ .DatadogServiceName }}",
   "agent_host": "{{ .DatadogCollectorHost }}",
   "agent_port": {{ .DatadogCollectorPort }},
-  "operation_name_override": "{{ .DatadogOperationNameOverride }}"
+  "operation_name_override": "{{ .DatadogOperationNameOverride }}",
+  "sample_rate": {{ .DatadogSampleRate }},
+  "dd.priority.sampling": {{ .DatadogPrioritySampling }}
 }`
 
 func createOpentracingCfg(cfg ngx_config.Configuration) error {