Added sampling for tracing (#1059)

gofr-dev · Sep 30, 2024 · d577a52 · d577a52
1 parent 2074f0b
commit d577a52
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Showing 3 changed files with 27 additions and 10 deletions.
diff --git a/docs/quick-start/observability/page.md b/docs/quick-start/observability/page.md
@@ -190,6 +190,7 @@ DB_PORT=3306
 # tracing configs
 TRACE_EXPORTER=zipkin
 TRACER_URL=http://localhost:2005/api/v2/spans
+TRACER_RATIO=0.1
 
 LOG_LEVEL=DEBUG
 ```
@@ -220,6 +221,7 @@ Add Jaeger Tracer configs in `.env` file, your .env will be updated to
 # tracing configs
 TRACE_EXPORTER=jaeger
 TRACER_URL=localhost:14317
+TRACER_RATIO=0.1
 ```
 
 Open {% new-tab-link title="jaeger" href="http://localhost:16686/trace/" /%} and search by TraceID (correlationID) to see the trace.
@@ -236,6 +238,7 @@ Add OTLP configs in `.env` file, your .env will be updated to
 # tracing configs 
 TRACE_EXPORTER=otlp
 TRACER_URL=localhost:4317
+TRACER_RATIO=0.1
 ```
 
 
@@ -251,6 +254,9 @@ Add GoFr Tracer configs in `.env` file, your .env will be updated to
 
 # tracing configs
 TRACE_EXPORTER=gofr
+TRACER_RATIO=0.1
 ```
 
+> NOTE: `TRACER_RATIO` refers to the proportion of traces that are exported through sampling. It ranges between 0 to 1. By default, this ratio is set to 1, meaning all traces are exported.
+
 Open {% new-tab-link title="gofr-tracer" href="https://tracer.gofr.dev/" /%} and search by TraceID (correlationID) to see the trace.
diff --git a/docs/references/configs/page.md b/docs/references/configs/page.md
@@ -87,6 +87,11 @@ This document lists all the configuration options supported by the GoFr framewor
 
 ---
 
+-  TRACER_RATIO
+-  Refers to the proportion of traces that are exported through sampling. It is optional configuration. By default, this ratio is set to 1.
+
+---
+
 -  TRACER_AUTH_KEY
 -  Authorization header for trace exporter requests.
 -  Supported for zipkin, jaeger.

diff --git a/pkg/gofr/gofr.go b/pkg/gofr/gofr.go
@@ -385,16 +385,6 @@ func (a *App) Migrate(migrationsMap map[int64]migration.Migrate) {
 }
 
 func (a *App) initTracer() {
-	tp := sdktrace.NewTracerProvider(
-		sdktrace.WithResource(resource.NewWithAttributes(
-			semconv.SchemaURL,
-			semconv.ServiceNameKey.String(a.container.GetAppName()),
-		)),
-	)
-	otel.SetTracerProvider(tp)
-	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
-	otel.SetErrorHandler(&otelErrorHandler{logger: a.container.Logger})
-
 	traceExporter := a.Config.Get("TRACE_EXPORTER")
 	tracerURL := a.Config.Get("TRACER_URL")
 
@@ -406,6 +396,22 @@ func (a *App) initTracer() {
 		return
 	}
 
+	traceRatio, err := strconv.ParseFloat(a.Config.GetOrDefault("TRACER_RATIO", "1"), 64)
+	if err != nil {
+		a.container.Error(err)
+	}
+
+	tp := sdktrace.NewTracerProvider(
+		sdktrace.WithResource(resource.NewWithAttributes(
+			semconv.SchemaURL,
+			semconv.ServiceNameKey.String(a.container.GetAppName()),
+		)),
+		sdktrace.WithSampler(sdktrace.ParentBased(sdktrace.TraceIDRatioBased(traceRatio))),
+	)
+	otel.SetTracerProvider(tp)
+	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
+	otel.SetErrorHandler(&otelErrorHandler{logger: a.container.Logger})
+
 	exporter, err := a.getExporter(traceExporter, tracerHost, tracerPort, tracerURL)
 
 	if err != nil {