fix(observability): tolerate otel schema URL conflicts in resource merge

resource.Merge returns ErrSchemaURLConflict when resource.Default()
and our semconv attributes use different schema versions (e.g. 1.39.0
vs 1.34.0 due to transitive dependency version skew). The merged
resource is still valid and usable, so we tolerate this specific error.

Author: samcm

pkg/observability/tracing.go

@@ -46,12 +46,17 @@ func SetupOTelSDK(ctx context.Context, tracerProvider *trace.TracerProvider) (sh
 }
 
 func NewResource(serviceName, serviceVersion string) (*resource.Resource, error) {
-	return resource.Merge(resource.Default(),
+	res, err := resource.Merge(resource.Default(),
 		resource.NewWithAttributes(semconv.SchemaURL,
 			semconv.ServiceName(serviceName),
 			semconv.ServiceVersion(serviceVersion),
 		),
 	)
+	if err != nil && !errors.Is(err, resource.ErrSchemaURLConflict) {
+		return nil, err
+	}
+
+	return res, nil
 }
 
 func NewHTTPTraceProvider(ctx context.Context, res *resource.Resource, httpOpts []otlptracehttp.Option, opts ...trace.TracerProviderOption) (*trace.TracerProvider, error) {