Define the fallback case for service.name

semantic_conventions/resource/service.yaml

@@ -11,6 +11,10 @@ groups:
           Logical name of the service.
         note: >
           MUST be the same for all instances of horizontally scaled services.
+          Although this is a required attribute, if the value was not specified, SDKs
+          MUST fallback to a language-specific name based on the running service
+          (typically inferred from process name, language, plaform, etc).
+          If this fallback fails, the name MUST default to `unknown_service`.
         examples: ["shoppingcart"]
       - id: namespace
         type: string

specification/resource/sdk.md

@@ -34,6 +34,10 @@ The interface MUST provide a way to create a new resource, from [`Attributes`](.
 Examples include a factory method or a constructor for a resource
 object. A factory method is recommended to enable support for cached objects.
 
+Note that certain **required** `Resource` specific attributes
+MUST have fallback values if they were not specified, e.g. `service.name`.
+See [Resource standard attributes]((semantic_conventions/README.md)).
+
 Required parameters:
 
 - [`Attributes`](../common/common.md#attributes)

specification/resource/semantic_conventions/README.md

@@ -46,7 +46,7 @@ Certain attribute groups in this document have a **Required** column. For these
 | `service.instance.id` | string | The string ID of the service instance. [3] | `627cc493-f310-47de-96bd-71410b7dec09` | Yes |
 | `service.version` | string | The version string of the service API or implementation. | `2.0.0` | No |
 
-**[1]:** MUST be the same for all instances of horizontally scaled services.
+**[1]:** MUST be the same for all instances of horizontally scaled services. Although this is a required attribute, if the value was not specified, SDKs MUST fallback to a language-specific name based on the running service (typically inferred from process name, language, plaform, etc). If this fallback fails, the name MUST default to `unknown_service`.
 
 **[2]:** A string value having a meaning that helps to distinguish a group of services, for example the team name that owns a group of services. `service.name` is expected to be unique within the same namespace. If `service.namespace` is not specified in the Resource then `service.name` is expected to be unique for all services that have no explicit namespace defined (so the empty/unspecified namespace is simply one more valid namespace). Zero-length namespace string is assumed equal to unspecified namespace.