Adding function to add a single attestor

attestation/factory.go

@@ -70,6 +70,12 @@ func (e ErrAttestationNotFound) Error() string {
 	return fmt.Sprintf("attestation not found: %v", string(e))
 }
 
+type ErrAttestorNotFound string
+
+func (e ErrAttestorNotFound) Error() string {
+	return fmt.Sprintf("attestor not found: %v", string(e))
+}
+
 func RegisterAttestation(name, predicateType string, run RunType, factoryFunc registry.FactoryFunc[Attestor], opts ...registry.Configurer) {
 	registrationEntry := attestorRegistry.Register(name, factoryFunc, opts...)
 	attestationsByType[predicateType] = registrationEntry
@@ -86,14 +92,32 @@ func FactoryByName(name string) (registry.FactoryFunc[Attestor], bool) {
 	return registrationEntry.Factory, ok
 }
 
+func GetAttestor(nameOrType string) (Attestor, error) {
+	attestors, err := GetAttestors([]string{nameOrType})
+	if err != nil {
+		return nil, err
+	}
+
+	if len(attestors) == 0 {
+		return nil, ErrAttestorNotFound(nameOrType)
+	}
+
+	return attestors[0], nil
+}
+
+// Deprecated: use AddAttestors instead
 func Attestors(nameOrTypes []string) ([]Attestor, error) {
+	return GetAttestors(nameOrTypes)
+}
+
+func GetAttestors(nameOrTypes []string) ([]Attestor, error) {
 	attestors := make([]Attestor, 0)
 	for _, nameOrType := range nameOrTypes {
 		factory, ok := FactoryByName(nameOrType)
 		if !ok {
 			factory, ok = FactoryByType(nameOrType)
 			if !ok {
-				return nil, ErrAttestationNotFound(nameOrType)
+				return nil, ErrAttestorNotFound(nameOrType)
 			}
 		}