Distributed Tracing OpenTelemetry Span Fields

As discussed in Context Propagation, message traces are made up of spans that are emitted at each point along the event mesh, consumed (and converted) by the Solace Open Telemetry Receiver, and sent to your chosen backend, which reassembles these spans and provides a visual view of the movement and processing of an event message. Each span that passes to the backend is made up of span fields and include span attributes (key-value pairs).

These tables list the OpenTelemetry span attributes in the event message that are sent to your observability backend (from the OpenTelemetry Collector with a configured Solace Open Telemetry Receiver).

Span Attribute	Description	Required?
TraceId	The traceID associated with the span.	Yes, by OpenTelemetry
SpanId	The spanID associated with the span.	Yes, by OpenTelemetry
TraceState	The state of the span trace.	No
Kind	The kind of span as per OpenTelemetry specifications (always Client).	Yes, by OpenTelemetry
StartTimeUnixNano	The start timestamp of the span.	Yes, by OpenTelemetry
EndTimeUnixNano	The end timestamp of the span.	Yes by OpenTelemetry
Status	The status of the OpenTelemetry span.	No
ParentSpanId	The spanID associated with the parent span.	No
messaging.system	The main messaging system of the event mesh.	Yes, by Solace
messaging.name	The name of the event broker.	Yes, by OpenTelemetry
service.instance.id	The message VPN of the event broker.	Yes, by Solace
service.version	The current version of the event broker.	Yes, by Solace
messaging.operation	The span operation (Receive or Send).	Yes, by Solace
messaging.protocol	The protocol used when the message was received by the event broker. Expected values are: SMF, REST, AMQP, MQTT.	No
messaging.protocol_version	The version of protocol used (For MQTT, it may be 3.1 or 5.0).	No
messaging.message_id	Application message ID of the PubSub+ event broker.	No
messaging.conversation_id	The correlationID (or conversation ID) of the message.	No
messaging.message_payload_size_bytes	The sum of the binary, XML, and metadata attachment sizes in the message payload.	No
messaging.solace.client_username	The name of the `client-username` object on the event broker that the client is bound to.	No
messaging.solace.client_name	The name of the client that is unique among all other clients on the event broker.	No
messaging.solace.replication_group_message_id	The replication group message ID of the received message.	No
messaging.solace.priority	The priority of the published message.	No
messaging.solace.ttl	The TTL of the published message.	No
messaging.solace.dmq_eligible	Indicates that the DMQ eligible bit was set in the message.	No
messaging.solace.dropped_enqueue_events_success	Indicates that the enqueueing of a dropped message succeeded.	No
messaging.solace.dropped_enqueue_events_failed	Indicates that the enqueueing of a dropped message failed.	No
messaging.solace.reply_to_topic	The reply-to topic of the received message.	No
messaging.solace.broker_receive_time_unix_nano	Indicates when the event broker first identifies that a message is to be traced.	No
messaging.solace.dropped_application_message_properties	If true, indicates that not all user properties in the message were captured in the `user_properties` because the limit was exceeded. (The event broker supports up to a total of 8KiB of user property data).	No
messaging.solace.delivery_mode	The delivery mode of the message (Persistent, Non-Persistent, or Direct).	No
messaging.source.kind	The type of the messaging source (queue or topic-endpoint).	Yes, by Solace
messaging.solace.message_replayed	Indicates whether the message has been replayed by the event broker.	No
messaging.solace.send.outcome	Displays the outcome of the sent message (accepted, rejected, released, delivery failed, flow unbound, transaction commit, transaction commit failed, and transaction rollback).	Yes, by Solace
net.host.ip	The IP Address that the event broker received the message on.	No
net.host.port	The port that the event broker received the message on.	No
net.peer.ip	The IP Address of the publishing client.	No
net.peer.port	The port of the publishing client.	No

Enqueue Events
Span Attribute	Description	Required?
event SetTimestamp(..)	The timestamp of when the enqueue decision was made.	Yes
event SetName(..)	The name of the enqueued queue or endpoint.	Yes

Enqueue Event Attributes
Span Attribute	Description	Required?
messaging.solace.destination_type	The type of the message destination (queue or topic-endpoint).	Yes
messaging.solace.partition_number	The number of the partition that the message was enqueued upon in a partitioned queue.	No
messaging.solace.enqueue_error_message	Describes why an enqueue operation failed.	No
messaging.solace.rejects_all_enqueues	Indicates that all other non-error enqueue events in this span are rejected. In other words, the message is not enqueued to any destination, regardless of what some enqueue events may indicate.	No

Transaction Events
Span Attribute	Description	Required?
event SetTimestamp	The timestamp of the initial decision for this message as part of the transaction operation.	Yes
event SetName	The name of the transaction event. For example, if a client requests a commit but the transaction rolls back due to an error, the name of the transaction event will be `commit`, and the status attribute will indicate why the commit failed. Expected values are: `commit`, `rollback`, `prepare`, `end`, `session_timeout`, and `rollback_only` .	Yes

Transaction Event Attributes
Span Attribute	Description	Required?
messaging.solace.transaction_initiator	Identifies if the (ADMIN) operation was performed using the management interface or by the CLIENT.	Yes
messaging.solace.transaction_id	The transaction ID. All messages that are part of the same transaction have the same value for this ID.	No
messaging.solace.transacted_session_name	The name of the local ID of the transaction event.	No
messaging.solace.transacted_session_id	The type of the local ID of the transaction event.	No
messaging.solace.transaction_error_message	Describes why a transaction operation failed.	No

Baggage Propagation
Span Attribute	Description	Required?
messaging.solace.message.baggage.<BAGGAGE_KEY NAME>	Provides the value associated with the Baggage Key Name that is provided through context propagation.	No
messaging.solace.message.baggage_metadata.<BAGGAGE_KEY NAME>	Provides the metadata value associated with the Baggage Key Name that is provided through context propagation.	No

For more information on traces, spans, span attributes (key-value pairs), and more, see OpenTelemetry Traces.

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