[checkout] fix kafka restart (#1590)

* fix kafka acks

* Update src/checkoutservice/main.go

Co-authored-by: Juliano Costa <julianocosta89@outlook.com>

* align attribute names with semantic conventions

* checkout: recover from kafka restart

---------

Co-authored-by: Juliano Costa <julianocosta89@outlook.com>

Author: puckpuck

CHANGELOG.md

@@ -47,6 +47,8 @@ the release.
   ([#1592](https://github.com/open-telemetry/opentelemetry-demo/pull/1592))
 * chore: Add service version to OTEL_RESOURCE_ATTRIBUTES
   ([#1594](https://github.com/open-telemetry/opentelemetry-demo/pull/1594))
+* [checkout] increase Kafka resiliency and observability
+  ([#1590](https://github.com/open-telemetry/opentelemetry-demo/pull/1590))
 
 ## 1.9.0
 

src/checkoutservice/kafka/producer.go

@@ -13,8 +13,18 @@ var (
 )
 
 func CreateKafkaProducer(brokers []string, log *logrus.Logger) (sarama.AsyncProducer, error) {
+	sarama.Logger = log
+
 	saramaConfig := sarama.NewConfig()
+	saramaConfig.Producer.Return.Successes = true
+	saramaConfig.Producer.Return.Errors = true
+
+	// Sarama has an issue in a single broker kafka if the kafka broker is restarted.
+	// This setting is to prevent that issue from manifesting itself, but may swallow failed messages.
+	saramaConfig.Producer.RequiredAcks = sarama.NoResponse
+
 	saramaConfig.Version = ProtocolVersion
+
 	// So we can know the partition and offset of messages.
 	saramaConfig.Producer.Return.Successes = true
 

src/checkoutservice/main.go

@@ -20,11 +20,15 @@ import (
 
 	"github.com/IBM/sarama"
 	"github.com/google/uuid"
+	otelhooks "github.com/open-feature/go-sdk-contrib/hooks/open-telemetry/pkg"
+	flagd "github.com/open-feature/go-sdk-contrib/providers/flagd/pkg"
+	"github.com/open-feature/go-sdk/openfeature"
 	"github.com/sirupsen/logrus"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"go.opentelemetry.io/contrib/instrumentation/runtime"
 	"go.opentelemetry.io/otel"
+	otelcodes "go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
 	"go.opentelemetry.io/otel/propagation"
@@ -34,9 +38,6 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials/insecure"
-	flagd "github.com/open-feature/go-sdk-contrib/providers/flagd/pkg"
-	"github.com/open-feature/go-sdk/openfeature"
-	otelhooks "github.com/open-feature/go-sdk-contrib/hooks/open-telemetry/pkg"
 	healthpb "google.golang.org/grpc/health/grpc_health_v1"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/proto"
@@ -440,13 +441,13 @@ func (cs *checkoutService) convertCurrency(ctx context.Context, from *pb.Money,
 }
 
 func (cs *checkoutService) chargeCard(ctx context.Context, amount *pb.Money, paymentInfo *pb.CreditCardInfo) (string, error) {
-    paymentService := cs.paymentSvcClient
+	paymentService := cs.paymentSvcClient
 	if cs.isFeatureFlagEnabled(ctx, "paymentServiceUnreachable") {
-        badAddress := "badAddress:50051"
-        c := mustCreateClient(context.Background(), badAddress)
+		badAddress := "badAddress:50051"
+		c := mustCreateClient(context.Background(), badAddress)
 		paymentService = pb.NewPaymentServiceClient(c)
-    }
-	
+	}
+
 	paymentResp, err := paymentService.Charge(ctx, &pb.ChargeRequest{
 		Amount:     amount,
 		CreditCard: paymentInfo})
@@ -504,18 +505,52 @@ func (cs *checkoutService) sendToPostProcessor(ctx context.Context, result *pb.O
 	span := createProducerSpan(ctx, &msg)
 	defer span.End()
 
-	cs.KafkaProducerClient.Input() <- &msg
-	successMsg := <-cs.KafkaProducerClient.Successes()
-	log.Infof("Successful to write message. offset: %v", successMsg.Offset)
+	// Send message and handle response
+	startTime := time.Now()
+	select {
+	case cs.KafkaProducerClient.Input() <- &msg:
+		log.Infof("Message sent to Kafka: %v", msg)
+		select {
+		case successMsg := <-cs.KafkaProducerClient.Successes():
+			span.SetAttributes(
+				attribute.Bool("messaging.kafka.producer.success", true),
+				attribute.Int("messaging.kafka.producer.duration_ms", int(time.Since(startTime).Milliseconds())),
+				attribute.KeyValue(semconv.MessagingKafkaMessageOffset(int(successMsg.Offset))),
+			)
+			log.Infof("Successful to write message. offset: %v, duration: %v", successMsg.Offset, time.Since(startTime))
+		case errMsg := <-cs.KafkaProducerClient.Errors():
+			span.SetAttributes(
+				attribute.Bool("messaging.kafka.producer.success", false),
+				attribute.Int("messaging.kafka.producer.duration_ms", int(time.Since(startTime).Milliseconds())),
+			)
+			span.SetStatus(otelcodes.Error, errMsg.Err.Error())
+			log.Errorf("Failed to write message: %v", errMsg.Err)
+		case <-ctx.Done():
+			span.SetAttributes(
+				attribute.Bool("messaging.kafka.producer.success", false),
+				attribute.Int("messaging.kafka.producer.duration_ms", int(time.Since(startTime).Milliseconds())),
+			)
+			span.SetStatus(otelcodes.Error, "Context cancelled: "+ctx.Err().Error())
+			log.Warnf("Context canceled before success message received: %v", ctx.Err())
+		}
+	case <-ctx.Done():
+		span.SetAttributes(
+			attribute.Bool("messaging.kafka.producer.success", false),
+			attribute.Int("messaging.kafka.producer.duration_ms", int(time.Since(startTime).Milliseconds())),
+		)
+		span.SetStatus(otelcodes.Error, "Failed to send: "+ctx.Err().Error())
+		log.Errorf("Failed to send message to Kafka within context deadline: %v", ctx.Err())
+		return
+	}
 
 	ffValue := cs.getIntFeatureFlag(ctx, "kafkaQueueProblems")
 	if ffValue > 0 {
 		log.Infof("Warning: FeatureFlag 'kafkaQueueProblems' is activated, overloading queue now.")
 		for i := 0; i < ffValue; i++ {
-    		go func(i int) {
-    		    cs.KafkaProducerClient.Input() <- &msg
+			go func(i int) {
+				cs.KafkaProducerClient.Input() <- &msg
 				_ = <-cs.KafkaProducerClient.Successes()
-            }(i)
+			}(i)
 		}
 		log.Infof("Done with #%d messages for overload simulation.", ffValue)
 	}
@@ -548,29 +583,29 @@ func createProducerSpan(ctx context.Context, msg *sarama.ProducerMessage) trace.
 }
 
 func (cs *checkoutService) isFeatureFlagEnabled(ctx context.Context, featureFlagName string) bool {
-    client := openfeature.NewClient("checkout")
-	
-    // Default value is set to false, but you could also make this a parameter.
-    featureEnabled, _ := client.BooleanValue(
-        ctx, 
-        featureFlagName, 
-        false, 
-        openfeature.EvaluationContext{},
-    )
-    
-    return featureEnabled
+	client := openfeature.NewClient("checkout")
+
+	// Default value is set to false, but you could also make this a parameter.
+	featureEnabled, _ := client.BooleanValue(
+		ctx,
+		featureFlagName,
+		false,
+		openfeature.EvaluationContext{},
+	)
+
+	return featureEnabled
 }
 
 func (cs *checkoutService) getIntFeatureFlag(ctx context.Context, featureFlagName string) int {
-    client := openfeature.NewClient("checkout")
-    
-    // Default value is set to 0, but you could also make this a parameter.
-    featureFlagValue, _ := client.IntValue(
-        ctx, 
-        featureFlagName, 
-        0, 
-        openfeature.EvaluationContext{},
-    )
-    
-    return int(featureFlagValue)
+	client := openfeature.NewClient("checkout")
+
+	// Default value is set to 0, but you could also make this a parameter.
+	featureFlagValue, _ := client.IntValue(
+		ctx,
+		featureFlagName,
+		0,
+		openfeature.EvaluationContext{},
+	)
+
+	return int(featureFlagValue)
 }