[craffit]

Services without a service.namespace (attribute unset or empty) got inconsistent identities: services and resource relations used an invented default namespace, while instances, service-graph relations and monitors broke on the missing value. The namespace mapping also created an empty-name component, which sync rejects.

Per the OTel semantic conventions, service.namespace is optional and the unset namespace is just another valid namespace; service.instance.id is unique within its (service.namespace, service.name) pair. This change encodes the unset namespace as the empty string everywhere:

• No namespace component is created for an unset or empty service.namespace.
• Component mappings, relation mappings and monitors all produce urn:opentelemetry:namespace/:service/<name> for such services. Service-graph relations no longer require the namespace dimension.
• Monitors build the URN prefix with one label_replace, because PromQL drops empty labels and a missing label in urnTemplate yields an incomplete health state.

Identifiers for services without a namespace change from namespace/default to namespace/; those components are recreated.

Tracking: https://github.com/StackVista/stackstate/issues/888

🤖 Generated with Claude Code

[craffit]

Switched to encoding an unset service.namespace as the empty string in identifiers (namespace/:service/<name>) instead of a separate namespace-free URN. Mappings no longer branch on the URN shape, and monitors need a single label_replace.

[craffit]

Paused. Instead of the label_replace workaround in the monitors, we want to evaluate CEL in urnTemplate (and other monitor template fields), consistent with the rest of our templating. This PR will be revisited once that is available. Tracking: https://github.com/StackVista/stackstate/issues/888