Trace Semantic Conventions

Status: Experimental

In OpenTelemetry spans can be created freely and it’s up to the implementor to annotate them with attributes specific to the represented operation. Spans represent specific operations in and between systems. Some of these operations represent calls that use well-known protocols like HTTP or database calls. Depending on the protocol and the type of operation, additional information is needed to represent and analyze a span correctly in monitoring systems. It is also important to unify how this attribution is made in different languages. This way, the operator will not need to learn specifics of a language and telemetry collected from polyglot (multi-language) micro-service environments can still be easily correlated and cross-analyzed.

The following semantic conventions for spans are defined:

• General: General semantic attributes that may be used in describing different kinds of operations.
• Compatibility: For spans generated by compatibility components, e.g. OpenTracing Shim layer.
• CloudEvents: Semantic Conventions for the CloudEvents spans.
• Cloud Providers: Semantic Conventions for cloud providers spans.
• Database: For SQL and NoSQL client call spans.
• Exceptions: For recording exceptions associated with a span.
• FaaS: For Function as a Service (e.g., AWS Lambda) spans.
• Feature Flags: For recording feature flag evaluations associated with a span.
• HTTP: For HTTP client and server spans.
• Messaging: For messaging systems (queues, publish/subscribe, etc.) spans.
• Object Stores: Semantic Conventions for object stores spans.
• RPC/RMI: For remote procedure call (e.g., gRPC) spans.

Apart from semantic conventions for traces, metrics, logs, and events, OpenTelemetry also defines the concept of overarching Resources with their own Resource Semantic Conventions.