added role impl From, more for compatability as only a single, fixed comment

Author: adwk67

rust/operator-binary/src/controller.rs

@@ -228,11 +228,6 @@ impl ValidatedCluster {
     }
 
     /// The single Hive role name (`metastore`).
-    pub fn role_name() -> RoleName {
-        RoleName::from_str(&HiveRole::MetaStore.to_string())
-            .expect("the metastore role name is a valid role name")
-    }
-
     /// Type-safe names for the per-cluster RBAC resources: the ServiceAccount shared by all
     /// Pods, its (namespaced) RoleBinding, and the operator-deployed ClusterRole it binds.
     pub fn cluster_resource_names(&self) -> role_utils::ResourceNames {
@@ -249,7 +244,7 @@ impl ValidatedCluster {
     ) -> ResourceNames {
         ResourceNames {
             cluster_name: self.name.clone(),
-            role_name: Self::role_name(),
+            role_name: HiveRole::MetaStore.into(),
             role_group_name: role_group_name.clone(),
         }
     }
@@ -269,7 +264,7 @@ impl ValidatedCluster {
     pub fn unversioned_recommended_labels(&self, role_group_name: &RoleGroupName) -> Labels {
         self.recommended_labels_with(
             &UNVERSIONED_PRODUCT_VERSION,
-            &Self::role_name(),
+            &HiveRole::MetaStore.into(),
             role_group_name,
         )
     }
@@ -294,12 +289,17 @@ impl ValidatedCluster {
 
     /// Recommended labels for a role-group resource.
     pub fn recommended_labels(&self, role_group_name: &RoleGroupName) -> Labels {
-        self.recommended_labels_for(&Self::role_name(), role_group_name)
+        self.recommended_labels_for(&HiveRole::MetaStore.into(), role_group_name)
     }
 
     /// Selector labels matching the pods of a role group.
     pub fn role_group_selector(&self, role_group_name: &RoleGroupName) -> Labels {
-        role_group_selector(self, &product_name(), &Self::role_name(), role_group_name)
+        role_group_selector(
+            self,
+            &product_name(),
+            &HiveRole::MetaStore.into(),
+            role_group_name,
+        )
     }
 
     /// Whether Kerberos is enabled for this cluster (a Kerberos `SecretClass` was configured).
@@ -663,7 +663,21 @@ pub(crate) mod test_support {
 mod tests {
     use std::str::FromStr;
 
+    use stackable_operator::v2::types::operator::RoleName;
+    use strum::IntoEnumIterator;
+
     use super::{RoleGroupName, test_support::*};
+    use crate::crd::HiveRole;
+
+    /// Locks the invariant behind the `expect` in the `From<HiveRole> for RoleName` impls:
+    /// every `HiveRole` variant (present and future) must serialise to a valid `RoleName`.
+    #[test]
+    fn every_hive_role_serialises_to_a_valid_role_name() {
+        for role in HiveRole::iter() {
+            let _: RoleName = (&role).into();
+            let _: RoleName = role.into();
+        }
+    }
 
     #[test]
     fn object_meta_sets_namespace_owner_and_recommended_labels() {

rust/operator-binary/src/controller/build/mod.rs

@@ -70,9 +70,6 @@ pub enum Error {
 ///
 /// `cluster_info` carries the Kubernetes cluster domain (needed by the Kerberos config); it is
 /// static cluster metadata, not a live client, so the build step stays client-free.
-///
-/// `service_account_name` is the name of the RBAC `ServiceAccount` the role-group Pods run under
-/// (RBAC resources are built and applied separately, in the reconcile step).
 pub fn build(
     cluster: &ValidatedCluster,
     cluster_info: &KubernetesClusterInfo,

rust/operator-binary/src/controller/build/resource/pdb.rs

@@ -23,7 +23,7 @@ pub fn build_pdb(
     let pdb = pod_disruption_budget_builder_with_role(
         cluster,
         &product_name(),
-        &ValidatedCluster::role_name(),
+        &HiveRole::MetaStore.into(),
         &operator_name(),
         &controller_name(),
     )

rust/operator-binary/src/crd/mod.rs

@@ -38,6 +38,7 @@ use stackable_operator::{
             kubernetes::{
                 ConfigMapName, ContainerName, ListenerClassName, SecretClassName, VolumeName,
             },
+            operator::RoleName,
         },
     },
     versioned::versioned,
@@ -261,6 +262,18 @@ pub enum HiveRole {
     MetaStore,
 }
 
+impl From<HiveRole> for RoleName {
+    fn from(value: HiveRole) -> Self {
+        RoleName::from_str(&value.to_string()).expect("a HiveRole is a valid role name")
+    }
+}
+
+impl From<&HiveRole> for RoleName {
+    fn from(value: &HiveRole) -> Self {
+        RoleName::from_str(&value.to_string()).expect("a HiveRole is a valid role name")
+    }
+}
+
 impl HiveRole {
     /// A Kerberos principal has three parts, with the form username/fully.qualified.domain.name@YOUR-REALM.COM.
     /// We only have one role and will use "hive" everywhere (which e.g. differs from the current hdfs implementation).