Semantic Conventions for Messaging Metrics

Status: Experimental

Warning Existing messaging instrumentations that are using v1.24.0 of this document (or prior) SHOULD NOT change the version of the messaging conventions that they emit until a transition plan to the (future) stable semantic conventions has been published. Conventions include, but are not limited to, attributes, metric and span names, and unit of measure.

Common attributes

All messaging metrics share the same set of attributes:

Attribute	Type	Description	Examples	Requirement Level	Stability
messaging.system	string	An identifier for the messaging system being used. See below for a list of well-known identifiers.	activemq	Required
error.type	string	Describes a class of error the operation ended with. [1]	amqp:decode-error; KAFKA_STORAGE_ERROR; channel-error	Conditionally Required [2]
messaging.destination.name	string	The message destination name [3]	MyQueue; MyTopic	Conditionally Required [4]
messaging.destination.template	string	Low cardinality representation of the messaging destination name [5]	/customers/{customerId}	Conditionally Required if available.
server.address	string	Server domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [6]	example.com; 10.1.2.80; /tmp/my.sock	Conditionally Required If available.
server.port	int	Server port number. [7]	80; 8080; 443	Recommended

[1]: The error.type SHOULD be predictable and SHOULD have low cardinality. Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low. Telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time when no additional filters are applied.

If the operation has completed successfully, instrumentations SHOULD NOT set error.type.

If a specific domain defines its own set of error identifiers (such as HTTP or gRPC status codes), it’s RECOMMENDED to:

• Use a domain-specific attribute
• Set error.type to capture all errors, regardless of whether they are defined within the domain-specific set or not.

[2]: If and only if the messaging operation has failed.

[3]: Destination name SHOULD uniquely identify a specific queue, topic or other entity within the broker. If the broker doesn’t have such notion, the destination name SHOULD uniquely identify the broker.

[4]: if and only if messaging.destination.name is known to have low cardinality. Otherwise, messaging.destination.template MAY be populated.

[5]: Destination names could be constructed from templates. An example would be a destination name involving a user name or product id. Although the destination name in this case is of high cardinality, the underlying template is of low cardinality and can be effectively used for grouping and aggregation.

[6]: Server domain name of the broker if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name.

[7]: When observed from the client side, and when communicating through an intermediary, server.port SHOULD represent the server port behind any intermediaries, for example proxies, if it’s available.

messaging.system has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
activemq	Apache ActiveMQ
aws_sqs	Amazon Simple Queue Service (SQS)
eventgrid	Azure Event Grid
eventhubs	Azure Event Hubs
servicebus	Azure Service Bus
gcp_pubsub	Google Cloud Pub/Sub
jms	Java Message Service
kafka	Apache Kafka
rabbitmq	RabbitMQ
rocketmq	Apache RocketMQ

error.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
_OTHER	A fallback error value to be used when the instrumentation doesn’t define a custom value.

Producer metrics

Metric: messaging.publish.duration

This metric is required.

When this metric is reported alongside a messaging publish span, the metric value SHOULD be the same as the corresponding span duration.

This metric SHOULD be specified with ExplicitBucketBoundaries of [ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ].

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.publish.duration	Histogram	s	Measures the duration of publish operation.

Metric: messaging.publish.messages

This metric is required when the messaging system supports batch publishing. It’s opt-in when the messaging system does not support batch publishing, since the message count can be derived from the messaging.publish.duration histogram.

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.publish.messages	Counter	{message}	Measures the number of published messages.

The need to report messaging.publish.messages depends on the messaging system capabilities and not application scenarios or client library limitations. For example, RabbitMQ does not support batch publishing and corresponding instrumentations don’t need to report messaging.publish.messages. Kafka supports both, single and batch publishing, and instrumentations MUST report messaging.publish.messages counter regardless of application scenarios or APIs available in the client library.

Consumer metrics

Metric: messaging.receive.duration

This metric is required for operations that are initiated by the application code (pull-based).

This metric SHOULD be specified with ExplicitBucketBoundaries of [ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ].

When this metric is reported alongside a messaging receive span, the metric value SHOULD be the same as the corresponding span duration.

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.receive.duration	Histogram	s	Measures the duration of receive operation.

Metric: messaging.receive.messages

This metric is required for batch receive operations. It’s opt-in when the messaging system does not support batch receive since the message count can be derived from the messaging.receive.duration histogram.

Note: The need to report messaging.receive.messages depends on the messaging system capabilities and not application scenarios or client library limitations.

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.receive.messages	Counter	{message}	Measures the number of received messages.

Metric: messaging.process.duration

This metric is required for operations that are not initiated by the application code (push-based deliver), and recommended for processing operations instrumented for pull-based scenarios.

When this metric is reported alongside a messaging process span, the metric value SHOULD be the same as the corresponding span duration.

This metric SHOULD be specified with ExplicitBucketBoundaries of [ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ].

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.process.duration	Histogram	s	Measures the duration of process operation.

Metric: messaging.process.messages

This metric is required for batch process operations, and recommended for batch processing operations instrumented for pull-based scenarios. It’s opt-in when the messaging system does not support batch processing since the message count can be derived from the messaging.process.duration histogram.

Note: The need to report messaging.process.messages depends on the messaging system capabilities and not application scenarios or client library limitations.

Name	Instrument Type	Unit (UCUM)	Description	Stability
messaging.process.messages	Counter	{message}	Measures the number of processed messages.