Merge pull request #669 from gfloyd/config-traceid-128bit

Add config option to generate 64 bit root span IDs

CHANGELOG.md

@@ -32,6 +32,17 @@
 
   Thanks to [@murphymj25](https://github.com/murphymj25) for the patch.
 
+* [PR #669](https://github.com/fabiolb/fabio/pull/669): Add option for downgrading tracing IDs to 64 bit
+
+  When tracing is enabled, fabio injected 128 bit root span IDs if necessary.
+  This can now be downgraded to 64 bit IDs by setting the new
+  `tracing.TraceID128Bit` option to false.
+
+  Existing 128 bit trace IDs in incoming requests are not affected by this
+  option and forwarded unchanged.
+
+  Thanks to [@gfloyd](https://github.com/gfloyd) for the patch.
+
 ### [v1.5.11](https://github.com/fabiolb/fabio/releases/tag/v1.5.11) - 25 Feb 2019
 
 #### Breaking Changes

config/config.go

@@ -175,6 +175,7 @@ type Tracing struct {
 	Topic          string
 	SamplerRate    float64
 	SpanHost       string
+	TraceID128Bit  bool
 }
 
 type AuthScheme struct {

config/default.go

@@ -100,5 +100,6 @@ var defaultConfig = &Config{
 		Topic:          "Fabiolb-Kafka-Topic",
 		SamplerRate:    -1,
 		SpanHost:       "localhost:9998",
+		TraceID128Bit:  true,
 	},
 }

config/load.go

@@ -204,6 +204,7 @@ func load(cmdline, environ, envprefix []string, props *properties.Properties) (c
 	f.StringVar(&cfg.Tracing.Topic, "tracing.Topic", defaultConfig.Tracing.Topic, "OpenTrace Collector Kafka Topic")
 	f.Float64Var(&cfg.Tracing.SamplerRate, "tracing.SamplerRate", defaultConfig.Tracing.SamplerRate, "OpenTrace sample rate percentage in decimal form")
 	f.StringVar(&cfg.Tracing.SpanHost, "tracing.SpanHost", defaultConfig.Tracing.SpanHost, "Host:Port info to add to spans")
+	f.BoolVar(&cfg.Tracing.TraceID128Bit, "tracing.TraceID128Bit", defaultConfig.Tracing.TraceID128Bit, "Generate 128 bit trace IDs")
 	f.BoolVar(&cfg.GlobMatchingDisabled, "glob.matching.disabled", defaultConfig.GlobMatchingDisabled, "Disable Glob Matching on routes, one of [true, false]")
 
 	f.StringVar(&cfg.Registry.Custom.Host, "registry.custom.host", defaultConfig.Registry.Custom.Host, "custom back end hostname/port")

trace/trace.go

@@ -47,12 +47,12 @@ func CreateCollector(collectorType, connectString, topic string) zipkin.Collecto
 	return collector
 }
 
-func CreateTracer(recorder zipkin.SpanRecorder, samplerRate float64) opentracing.Tracer {
+func CreateTracer(recorder zipkin.SpanRecorder, samplerRate float64, traceID128Bit bool) opentracing.Tracer {
 	tracer, err := zipkin.NewTracer(
 		recorder,
 		zipkin.WithSampler(zipkin.NewBoundarySampler(samplerRate, 1)),
 		zipkin.ClientServerSameSpan(false),
-		zipkin.TraceID128Bit(true),
+		zipkin.TraceID128Bit(traceID128Bit),
 	)
 
 	if err != nil {
@@ -93,7 +93,7 @@ func InitializeTracer(traceConfig *config.Tracing) {
 	// Create a new Zipkin Collector, Recorder, and Tracer
 	collector := CreateCollector(traceConfig.CollectorType, traceConfig.ConnectString, traceConfig.Topic)
 	recorder := zipkin.NewRecorder(collector, false, traceConfig.SpanHost, traceConfig.ServiceName)
-	tracer := CreateTracer(recorder, traceConfig.SamplerRate)
+	tracer := CreateTracer(recorder, traceConfig.SamplerRate, traceConfig.TraceID128Bit)
 
 	// Set the Zipkin Tracer created above to the GlobalTracer
 	opentracing.SetGlobalTracer(tracer)