Add support for filtering commands when tracing

Signed-off-by: Jason Parraga <[email protected]>

Author: Sovietaced

extra/redisotel/config.go

@@ -1,6 +1,7 @@
 package redisotel
 
 import (
+	"github.com/redis/go-redis/v9"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
@@ -21,6 +22,7 @@ type config struct {
 
 	dbStmtEnabled bool
 	callerEnabled bool
+	filter        func(cmd redis.Cmder) bool
 
 	// Metrics options.
 
@@ -124,6 +126,14 @@ func WithCallerEnabled(on bool) TracingOption {
 	})
 }
 
+// WithCommandFilter allows filtering of commands when tracing to omit commands that may have sensitive details like
+// passwords.
+func WithCommandFilter(filter func(cmd redis.Cmder) bool) TracingOption {
+	return tracingOption(func(conf *config) {
+		conf.filter = filter
+	})
+}
+
 //------------------------------------------------------------------------------
 
 type MetricsOption interface {

extra/redisotel/tracing.go

@@ -102,6 +102,12 @@ func (th *tracingHook) DialHook(hook redis.DialHook) redis.DialHook {
 func (th *tracingHook) ProcessHook(hook redis.ProcessHook) redis.ProcessHook {
 	return func(ctx context.Context, cmd redis.Cmder) error {
 
+		// Check if the command should be filtered out
+		if th.conf.filter != nil && th.conf.filter(cmd) {
+			// If so, just call the next hook
+			return hook(ctx, cmd)
+		}
+
 		attrs := make([]attribute.KeyValue, 0, 8)
 		if th.conf.callerEnabled {
 			fn, file, line := funcFileLine("github.com/redis/go-redis")

extra/redisotel/tracing_test.go

@@ -95,6 +95,63 @@ func TestWithoutCaller(t *testing.T) {
 	}
 }
 
+func TestWithCommandFilter(t *testing.T) {
+
+	t.Run("filter out ping command", func(t *testing.T) {
+		provider := sdktrace.NewTracerProvider()
+		hook := newTracingHook(
+			"",
+			WithTracerProvider(provider),
+			WithCommandFilter(func(cmd redis.Cmder) bool {
+				return cmd.Name() == "ping"
+			}),
+		)
+		ctx, span := provider.Tracer("redis-test").Start(context.TODO(), "redis-test")
+		cmd := redis.NewCmd(ctx, "ping")
+		defer span.End()
+
+		processHook := hook.ProcessHook(func(ctx context.Context, cmd redis.Cmder) error {
+			innerSpan := trace.SpanFromContext(ctx).(sdktrace.ReadOnlySpan)
+			if innerSpan.Name() != "redis-test" || innerSpan.Name() == "ping" {
+				t.Fatalf("ping command should not be traced")
+			}
+
+			return nil
+		})
+		err := processHook(ctx, cmd)
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	t.Run("do not filter ping command", func(t *testing.T) {
+		provider := sdktrace.NewTracerProvider()
+		hook := newTracingHook(
+			"",
+			WithTracerProvider(provider),
+			WithCommandFilter(func(cmd redis.Cmder) bool {
+				return false // never filter
+			}),
+		)
+		ctx, span := provider.Tracer("redis-test").Start(context.TODO(), "redis-test")
+		cmd := redis.NewCmd(ctx, "ping")
+		defer span.End()
+
+		processHook := hook.ProcessHook(func(ctx context.Context, cmd redis.Cmder) error {
+			innerSpan := trace.SpanFromContext(ctx).(sdktrace.ReadOnlySpan)
+			if innerSpan.Name() != "ping" {
+				t.Fatalf("ping command should be traced")
+			}
+
+			return nil
+		})
+		err := processHook(ctx, cmd)
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+}
+
 func TestTracingHook_DialHook(t *testing.T) {
 	imsb := tracetest.NewInMemoryExporter()
 	provider := sdktrace.NewTracerProvider(sdktrace.WithSyncer(imsb))