Unclear usage of semconv MessagingSystemKey about opentelemetry-go

[dmathieu]

Would the semantic conventions doc be more helpful there?
https://github.com/open-telemetry/semantic-conventions/blob/75f9d428a45f9e779b72c34d9ac3c00625b7472a/docs/attributes-registry/messaging.md

Improved documentation is always welcome though. Do you want to open a PR?

[joreetz-otto]

Thanks for this super fast reply.
This documentation is also not clear in this case for me.

An identifier for the messaging system being used. See below for a list of well-known identifiers.

I will for sure update the docs when i know the answer to this

I will open an issue in the linked repo.

[dmathieu]

I'm not sure I understand the source/destination messaging system there.
If you have a span reading from Kafka, that's what its messaging system is. If it's writing to RabbitMQ, that's what its messaging system is.

If you have a span both reading and writing, maybe there should be two spans to properly observe what's happening?

[pellared]

The docs are generated from https://github.com/open-telemetry/semantic-conventions/blob/v1.24.0/model/registry/messaging.yaml#L210-L245

Do you find these not good enough?

• opentelemetry-go/semconv/v1.24.0/attribute_group.go

  Lines 2727 to 2735 in 6ead8d8

  	// MessagingSystemKey is the attribute Key conforming to the
  	// "messaging.system" semantic conventions. It represents an identifier for
  	// the messaging system being used. See below for a list of well-known
  	// identifiers.
  	//
  	// Type: Enum
  	// RequirementLevel: Optional
  	// Stability: experimental
  	MessagingSystemKey = attribute.Key("messaging.system")

• opentelemetry-go/semconv/v1.24.0/attribute_group.go

  Lines 2767 to 2788 in 6ead8d8

  	var (
  	// Apache ActiveMQ
  	MessagingSystemActivemq = MessagingSystemKey.String("activemq")
  	// Amazon Simple Queue Service (SQS)
  	MessagingSystemAWSSqs = MessagingSystemKey.String("aws_sqs")
  	// Azure Event Grid
  	MessagingSystemAzureEventgrid = MessagingSystemKey.String("azure_eventgrid")
  	// Azure Event Hubs
  	MessagingSystemAzureEventhubs = MessagingSystemKey.String("azure_eventhubs")
  	// Azure Service Bus
  	MessagingSystemAzureServicebus = MessagingSystemKey.String("azure_servicebus")
  	// Google Cloud Pub/Sub
  	MessagingSystemGCPPubsub = MessagingSystemKey.String("gcp_pubsub")
  	// Java Message Service
  	MessagingSystemJms = MessagingSystemKey.String("jms")
  	// Apache Kafka
  	MessagingSystemKafka = MessagingSystemKey.String("kafka")
  	// RabbitMQ
  	MessagingSystemRabbitmq = MessagingSystemKey.String("rabbitmq")
  	// Apache RocketMQ
  	MessagingSystemRocketmq = MessagingSystemKey.String("rocketmq")
  	)

[joreetz-otto]

@dmathieu yes I think you are right that one should have a separate span for receive and send but even though you want to give some metadata about what happens inside the span and thats what these attributes are for in my opinion.
@pellared I cant answer my question from this documentation, so...

I just saw that there is the MessagingOperationKey which should resolve my issue.