fix: make container name accessor infallible (#874)

* fix: make container name accessor infallible

* changelog

* review feedback

Author: adwk67

CHANGELOG.md

@@ -25,7 +25,7 @@ All notable changes to this project will be documented in this file.
   StatefulSets created by older operator versions cannot be updated in place: after the
   operator upgrade, delete each broker, coordinator and router StatefulSet so that the operator
   immediately recreates it with the new labels ([#865]).
-- Make operations infallible where dependent on static inputs ([#869]).
+- Make operations infallible where dependent on static inputs ([#869], [#874]).
 
 ### Fixed
 
@@ -43,6 +43,7 @@ All notable changes to this project will be documented in this file.
 [#865]: https://github.com/stackabletech/druid-operator/pull/865
 [#867]: https://github.com/stackabletech/druid-operator/pull/867
 [#869]: https://github.com/stackabletech/druid-operator/pull/869
+[#874]: https://github.com/stackabletech/druid-operator/pull/874
 
 ## [26.7.0] - 2026-07-21
 

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

@@ -130,11 +130,9 @@ pub fn build_rolegroup_statefulset(
     let druid_tls_security = &cluster.cluster_config.druid_tls_security;
     let druid_auth_config = &cluster.cluster_config.druid_auth_config;
     // prepare container builder
-    let prepare_container_name = Container::Prepare.to_container_name();
-    let mut cb_prepare = new_container_builder(&prepare_container_name);
+    let mut cb_prepare = new_container_builder(Container::Prepare.name());
     // druid container builder
-    let druid_container_name = Container::Druid.to_container_name();
-    let mut cb_druid = new_container_builder(&druid_container_name);
+    let mut cb_druid = new_container_builder(Container::Druid.name());
     // init pod builder
     let mut pb = PodBuilder::new();
     pb.affinity(&merged_rolegroup_config.affinity);
@@ -158,7 +156,7 @@ pub fn build_rolegroup_statefulset(
         // otherwise the output of the following commands will not be captured!
         prepare_container_commands.push(product_logging::framework::capture_shell_output(
             STACKABLE_LOG_DIR,
-            prepare_container_name.as_ref(),
+            Container::Prepare.name().as_ref(),
             log_config,
         ));
     }
@@ -362,7 +360,7 @@ pub fn build_rolegroup_statefulset(
     // config volume; the validated aggregator address comes from the up-front `ValidatedLogging`.
     if let Some(vector_log_config) = &merged_rolegroup_config.logging.vector_container {
         pb.add_container(vector_container(
-            &Container::Vector.to_container_name(),
+            Container::Vector.name(),
             resolved_product_image,
             vector_log_config,
             &resource_names,

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

@@ -497,11 +497,20 @@ pub enum Container {
     Vector,
 }
 
+// Typed container names. They must match the strum `Display` (kebab-case) of the variants above,
+// which is pinned by a unit test.
+constant!(DRUID_CONTAINER_NAME: ContainerName = "druid");
+constant!(PREPARE_CONTAINER_NAME: ContainerName = "prepare");
+constant!(VECTOR_CONTAINER_NAME: ContainerName = "vector");
+
 impl Container {
-    /// Returns the typed container name for this container.
-    pub fn to_container_name(&self) -> ContainerName {
-        ContainerName::from_str(&self.to_string())
-            .expect("a Container always serializes to a valid container name")
+    /// The typed container name of this variant.
+    pub fn name(&self) -> &'static ContainerName {
+        match self {
+            Container::Druid => &DRUID_CONTAINER_NAME,
+            Container::Prepare => &PREPARE_CONTAINER_NAME,
+            Container::Vector => &VECTOR_CONTAINER_NAME,
+        }
     }
 }
 
@@ -901,10 +910,20 @@ pub fn build_string_list(strings: &[String]) -> String {
 #[cfg(test)]
 mod tests {
     use stackable_operator::versioned::test_utils::RoundtripTestData;
+    use strum::IntoEnumIterator;
 
     use super::*;
     use crate::crd::v1alpha1;
 
+    /// The typed container names returned by `name` must agree with the strum `Display`
+    /// of `Container`, which the logging configuration still uses as the per-container key.
+    #[test]
+    fn container_names_match_display() {
+        for container in Container::iter() {
+            assert_eq!(container.name().to_string(), container.to_string());
+        }
+    }
+
     #[test]
     fn test_constants() {
         // Test that dereferencing the constants does not panic.
@@ -916,6 +935,9 @@ mod tests {
         let _ = *COOKIE_PASSPHRASE_ENV;
         let _ = *COOKIE_PASSPHRASE_SECRET_KEY;
         let _ = *DRUID_DEFAULT_LISTENER_CLASS;
+        let _ = *DRUID_CONTAINER_NAME;
+        let _ = *PREPARE_CONTAINER_NAME;
+        let _ = *VECTOR_CONTAINER_NAME;
     }
 
     impl RoundtripTestData for v1alpha1::DruidClusterSpec {