Improve Tracing Configurations

CHANGELOG.md

@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+- Split up the tracing configuration options so user can decide exactly what gets traced and when [#104](https://github.com/xmidt-org/candlelight/pull/104)
 
 ## [v0.0.14]
 - Updated traceProvider to only sample traces with remote parents (configurable) [#100](https://github.com/xmidt-org/candlelight/pull/100)

config.go

@@ -40,10 +40,15 @@ type Config struct {
 	// TracerProvider.
 	Providers map[string]ProviderConstructor `json:"-"`
 
-	// SampleLocalTraces defines whether local traces will be created and exported.
-	// SampleLocalTraces = true if you want to create and export local traces. Otherwise,
-	// only remote traces/spans will be sampled.
-	SampleLocalTraces bool `json:"sampleLocalTraces"`
+	// ParentBased and NoParent dictate if and when new spans should be created.
+	// ParentBased = "ignore" (default), tracing is effectively turned off and the "NoParent" value is ignored
+	// ParentBased = "honor", the sampling decision is made by the parent of the span
+	ParentBased string `json:"parentBased"`
+
+	// NoParent decided if a root span should be initiated if there's no parent
+	// This value is ignored if ParentBased = "ignore"
+	// "never" is the default value
+	NoParent string `json:"noParent"`
 }
 
 // TraceConfig will be used in TraceMiddleware to use config and TraceProvider

tracerProvider.go

@@ -38,6 +38,8 @@ import (
 var (
 	ErrTracerProviderNotFound    = errors.New("TracerProvider builder could not be found")
 	ErrTracerProviderBuildFailed = errors.New("Failed building TracerProvider")
+	ErrInvalidParentBasedValue   = errors.New("Invalid ParentBased value provided in configuration")
+	ErrInvalidNoParentValue      = errors.New("Invalid No Parent value provided in configuration")
 )
 
 // DefaultTracerProvider is used when no provider is given.
@@ -57,20 +59,42 @@ func ConfigureTracerProvider(config Config) (trace.TracerProvider, error) {
 	// Handling camelcase of provider.
 	config.Provider = strings.ToLower(config.Provider)
 	providerConfig := config.Providers[config.Provider]
-	sampleLocalTraces := config.SampleLocalTraces
+	parentBasedTracing := config.ParentBased
+	noParentTracing := config.NoParent
 	if providerConfig == nil {
 		providerConfig = providersConfig[config.Provider]
 	}
 	if providerConfig == nil {
 		return nil, fmt.Errorf("%w for provider %s", ErrTracerProviderNotFound, config.Provider)
 	}
 
-	// Setting up trace sampler based on SampleLocalTraces value in config file
-	// Default behavior: never sample local traces
-	sampler := sdktrace.ParentBased(sdktrace.NeverSample())
+	// If parentBased value is empty, use default value
+	if parentBasedTracing == "" {
+		parentBasedTracing = "ignore"
+	}
+
+	// If noParent value is empty, use default value
+	if noParentTracing == "" {
+		noParentTracing = "never"
+	}
+
+	// Setting up trace sampler based on ParentBased and NoParent values in the config
+	var sampler sdktrace.Sampler
 
-	if sampleLocalTraces {
-		sampler = sdktrace.ParentBased(sdktrace.AlwaysSample())
+	if parentBasedTracing == "ignore" {
+		sampler = sdktrace.NeverSample()
+	} else if parentBasedTracing == "honor" {
+		if noParentTracing == "never" {
+			sampler = sdktrace.ParentBased(sdktrace.NeverSample())
+
+		} else if noParentTracing == "always" {
+			sampler = sdktrace.ParentBased(sdktrace.AlwaysSample())
+
+		} else {
+			return nil, ErrInvalidNoParentValue
+		}
+	} else {
+		return nil, ErrInvalidParentBasedValue
 	}
 
 	provider, err := providerConfig(config, sampler)

tracerProvider_test.go

@@ -34,17 +34,82 @@ func TestConfigureTracerProvider(t *testing.T) {
 		{
 			Description: "Otlp/gRPC: Valid",
 			Config: Config{
-				Provider: "otlp/grpc",
-				Endpoint: "http://localhost",
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "ignore",
+				NoParent:    "never",
+			},
+		},
+		{
+			Description: "Otlp/gRPC: Valid",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "honor",
+				NoParent:    "never",
+			},
+		},
+		{
+			Description: "Otlp/gRPC: Valid",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "honor",
+				NoParent:    "always",
+			},
+		},
+		{
+			Description: "Otlp/gRPC: Valid",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "ignore",
+				NoParent:    "always",
 			},
 		},
 		{
 			Description: "Otlp/gRPC: Missing Endpoint",
 			Config: Config{
-				Provider: "otlp/grpc",
+				Provider:    "otlp/grpc",
+				ParentBased: "ignore",
+				NoParent:    "never",
 			},
 			Err: ErrTracerProviderBuildFailed,
 		},
+		{
+			Description: "Valid Missing ParentBased Value",
+			Config: Config{
+				Provider: "otlp/grpc",
+				Endpoint: "http://localhost",
+			},
+		},
+		{
+			Description: "Valid Missing NoParent Value",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "honor",
+			},
+		},
+		{
+			Description: "Invalid ParentBased Value",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "dishonor",
+			},
+			Err: ErrInvalidParentBasedValue,
+		},
+		{
+			Description: "Invalid No Parent Value",
+			Config: Config{
+				Provider:    "otlp/grpc",
+				Endpoint:    "http://localhost",
+				ParentBased: "honor",
+				NoParent:    "sometimes",
+			},
+			Err: ErrInvalidNoParentValue,
+		},
 		{
 			Description: "Otlp/HTTP: Valid",
 			Config: Config{