Add config param

cmd/trace-agent/agent.go

@@ -183,7 +183,7 @@ func (a *Agent) Process(t model.Trace) {
 	// All traces should go through either through the normal score sampler or
 	// the one dedicated to errors
 	samplers := make([]*Sampler, 0, 2)
-	if traceContainsError(t) {
+	if !a.conf.DisableDedicatedErrorsSampling && traceContainsError(t) {
 		samplers = append(samplers, a.ErrorsScoreSampler)
 	} else {
 		samplers = append(samplers, a.ScoreSampler)

config/agent.go

@@ -81,6 +81,9 @@ type AgentConfig struct {
 
 	// infrastructure agent binary
 	DDAgentBin string // DDAgentBin will be "" for Agent5 scenarios
+
+	// disable the dedicated error sampler
+	DisableDedicatedErrorsSampling bool
 }
 
 // NewDefaultAgentConfig returns a configuration with the default values
@@ -121,6 +124,8 @@ func NewDefaultAgentConfig() *AgentConfig {
 
 		Ignore:                make(map[string][]string),
 		AnalyzedRateByService: make(map[string]float64),
+
+		DisableDedicatedErrorsSampling: false,
 	}
 }
 

config/agent_test.go

@@ -151,6 +151,8 @@ func TestUndocumentedYamlConfig(t *testing.T) {
 	assert.Equal(1.0, agentConfig.AnalyzedRateByService["db"])
 	assert.Equal(0.9, agentConfig.AnalyzedRateByService["web"])
 	assert.Equal(0.5, agentConfig.AnalyzedRateByService["index"])
+	// error sampling
+	assert.Equal(true, agentConfig.DisableDedicatedErrorsSampling)
 }
 
 func TestConfigNewIfExists(t *testing.T) {

config/merge_ini.go

@@ -197,6 +197,11 @@ func mergeIniConfig(c *AgentConfig, conf *File) error {
 	c.StatsWriterConfig = readStatsWriterConfig(conf, "trace.writer.stats")
 	c.TraceWriterConfig = readTraceWriterConfig(conf, "trace.writer.traces")
 
+	// undocumented
+	if v := strings.ToLower(conf.GetDefault("trace.sampler", "disable_dedicated_errors_sampling", "")); v == "yes" || v == "true" {
+		c.DisableDedicatedErrorsSampling = true
+	}
+
 	return nil
 }
 

config/merge_yaml.go

@@ -38,16 +38,17 @@ type proxy struct {
 }
 
 type traceAgent struct {
-	Enabled            *bool          `yaml:"enabled"`
-	Endpoint           string         `yaml:"apm_dd_url"`
-	Env                string         `yaml:"env"`
-	ExtraSampleRate    float64        `yaml:"extra_sample_rate"`
-	MaxTracesPerSecond float64        `yaml:"max_traces_per_second"`
-	IgnoreResources    []string       `yaml:"ignore_resources"`
-	LogFilePath        string         `yaml:"log_file"`
-	ReplaceTags        []*ReplaceRule `yaml:"replace_tags"`
-	ReceiverPort       int            `yaml:"receiver_port"`
-	APMNonLocalTraffic *bool          `yaml:"apm_non_local_traffic"`
+	Enabled                        *bool          `yaml:"enabled"`
+	Endpoint                       string         `yaml:"apm_dd_url"`
+	Env                            string         `yaml:"env"`
+	ExtraSampleRate                float64        `yaml:"extra_sample_rate"`
+	MaxTracesPerSecond             float64        `yaml:"max_traces_per_second"`
+	DisableDedicatedErrorsSampling bool           `yaml:"disable_dedicated_errors_sampling"`
+	IgnoreResources                []string       `yaml:"ignore_resources"`
+	LogFilePath                    string         `yaml:"log_file"`
+	ReplaceTags                    []*ReplaceRule `yaml:"replace_tags"`
+	ReceiverPort                   int            `yaml:"receiver_port"`
+	APMNonLocalTraffic             *bool          `yaml:"apm_non_local_traffic"`
 
 	WatchdogMaxMemory float64 `yaml:"max_memory"`
 	WatchdogMaxCPUPct float64 `yaml:"max_cpu_percent"`
@@ -230,6 +231,9 @@ func mergeYamlConfig(agentConf *AgentConfig, yc *YamlAgentConfig) error {
 		agentConf.DDAgentBin = yc.TraceAgent.DDAgentBin
 	}
 
+	// undocumented
+	agentConf.DisableDedicatedErrorsSampling = yc.TraceAgent.DisableDedicatedErrorsSampling
+
 	return nil
 }
 

config/test_cases/undocumented.yaml

@@ -4,6 +4,7 @@ apm_config:
   extra_sample_rate: 0.33
   max_traces_per_second: 100.0
   receiver_port: 25
+  disable_dedicated_errors_sampling: true
   max_cpu_percent: 7
   max_connections: 50
   max_memory: 30000000