Add opentracing.ref_type semantic convention. (#2297)

CHANGELOG.md

@@ -65,6 +65,8 @@ release.
   ([2100](https://github.com/open-telemetry/opentelemetry-specification/pull/2100))
 - Add JVM memory runtime semantic
   conventions. ([#2272](https://github.com/open-telemetry/opentelemetry-specification/pull/2272))
+- Add opentracing.ref_type semantic convention.
+  ([#2297](https://github.com/open-telemetry/opentelemetry-specification/pull/2297))
 
 ### Compatibility
 

semantic_conventions/trace/compatibility.yaml

@@ -0,0 +1,20 @@
+groups:
+  - id: opentracing
+    prefix: opentracing
+    brief: 'This document defines semantic conventions for the OpenTracing Shim'
+    note: >
+        These conventions are used by the OpenTracing Shim layer.
+    attributes:
+      - id: ref_type
+        brief: 'Parent-child Reference type'
+        note: >
+            The causal relationship between a child Span and a parent Span.
+        type:
+          allow_custom_values: false
+          members:
+            - id: child_of
+              value: 'child_of'
+              brief: 'The parent Span depends on the child Span in some capacity'
+            - id: follows_from
+              value: 'follows_from'
+              brief: 'The parent Span does not depend in any way on the result of the child Span'

specification/compatibility/opentracing.md

@@ -143,8 +143,9 @@ If a list of `Span` references is specified, the first `SpanContext`
 with **Child Of** type in the entire list is used as parent, else the
 the first `SpanContext` is used as parent. All values in the list
 MUST be added as [Link](../trace/api.md)s with the reference type value
-as a `Link` attribute, i.e. `opentracing.ref_type` set to `follows_from` or
-`child_of`.
+as a `Link` attribute, i.e.
+[opentracing.ref_type](../trace/semantic_conventions/compatibility.md#opentracing)
+set to `follows_from` or `child_of`.
 
 If a list of `Span` references is specified, the union of their
 `Baggage` values MUST be used as the initial `Baggage` of the newly created

specification/trace/semantic_conventions/README.md

@@ -22,6 +22,7 @@ The following semantic conventions for spans are defined:
 * [Messaging](messaging.md): For messaging systems (queues, publish/subscribe, etc.) spans.
 * [FaaS](faas.md): For [Function as a Service](https://en.wikipedia.org/wiki/Function_as_a_service) (e.g., AWS Lambda) spans.
 * [Exceptions](exceptions.md): For recording exceptions associated with a span.
+* [Compatibility](compatibility.md): For spans generated by compatibility components, e.g. OpenTracing Shim layer.
 
 The following library-specific semantic conventions are defined:
 

specification/trace/semantic_conventions/compatibility.md

@@ -0,0 +1,36 @@
+# Semantic conventions for Compatibility components
+
+**Status**: [Experimental](../../document-status.md)
+
+This document defines trace semantic conventions used by the
+compatibility components, e.g. OpenTracing Shim layer.
+
+<!-- Re-generate TOC with `markdown-toc --no-first-h1 -i` -->
+
+<!-- toc -->
+
+- [OpenTracing](#opentracing)
+
+<!-- tocstop -->
+
+## OpenTracing
+
+`Link`s created by the OpenTracing Shim MUST set `opentracing.ref_type`
+with one of the accepted values, describing the direct causal relationships
+between a child Span and a parent Span, as defined by
+[OpenTracing](https://github.com/opentracing/specification/blob/master/specification.md).
+
+<!-- semconv opentracing -->
+| Attribute  | Type | Description  | Examples  | Required |
+|---|---|---|---|---|
+| `opentracing.ref_type` | string | Parent-child Reference type [1] | `child_of` | No |
+
+**[1]:** The causal relationship between a child Span and a parent Span.
+
+`opentracing.ref_type` MUST be one of the following:
+
+| Value  | Description |
+|---|---|
+| `child_of` | The parent Span depends on the child Span in some capacity |
+| `follows_from` | The parent Span does not depend in any way on the result of the child Span |
+<!-- endsemconv -->