Make pod overrides usable without roles. (#616)

Required for: stackabletech/spark-k8s-operator#256

- Make pub_overrides_schema public.
- Make PodTemplateSpec implement Atomic.
- Update CHANGELOG.md


Co-authored-by: Sebastian Bernauer <sebastian.bernauer@stackable.de>

Author: razvan

CHANGELOG.md

@@ -8,7 +8,12 @@ All notable changes to this project will be documented in this file.
 
 - Secrets can now be requested in a custom format ([#610]).
 
+### Changed
+
+- Make pod overrides usable independently of roles (like in the case of the Spark operator) ([#616])
+
 [#610]: https://github.com/stackabletech/operator-rs/pull/610
+[#616]: https://github.com/stackabletech/operator-rs/pull/616
 
 ## [0.42.2] - 2023-06-27
 

src/config/fragment.rs

@@ -15,6 +15,7 @@ use super::merge::Merge;
 #[cfg(doc)]
 use crate::role_utils::{Role, RoleGroup};
 
+use k8s_openapi::api::core::v1::PodTemplateSpec;
 use snafu::Snafu;
 
 pub use stackable_operator_derive::Fragment;
@@ -192,6 +193,17 @@ impl<T: FromFragment> FromFragment for Option<T> {
         }
     }
 }
+impl FromFragment for PodTemplateSpec {
+    type Fragment = PodTemplateSpec;
+    type RequiredFragment = PodTemplateSpec;
+
+    fn from_fragment(
+        fragment: Self::Fragment,
+        _validator: Validator,
+    ) -> Result<Self, ValidationError> {
+        Ok(fragment)
+    }
+}
 
 /// Validates a [`Fragment`](`FromFragment::Fragment`), and turns it into its corresponding [`FromFragment`] type if successful.
 ///

src/config/merge.rs

@@ -1,6 +1,7 @@
 use k8s_openapi::{
-    api::core::v1::{NodeAffinity, PodAffinity, PodAntiAffinity},
+    api::core::v1::{NodeAffinity, PodAffinity, PodAntiAffinity, PodTemplateSpec},
     apimachinery::pkg::{api::resource::Quantity, apis::meta::v1::LabelSelector},
+    DeepMerge,
 };
 use std::{
     collections::{btree_map, hash_map, BTreeMap, HashMap},
@@ -83,6 +84,11 @@ impl<K: Hash + Eq + Clone, V: Merge + Clone> Merge for HashMap<K, V> {
         }
     }
 }
+impl Merge for PodTemplateSpec {
+    fn merge(&mut self, defaults: &Self) {
+        self.merge_from(defaults.clone())
+    }
+}
 
 /// Moving version of [`Merge::merge`], to produce slightly nicer test output
 pub fn merge<T: Merge>(mut overrides: T, defaults: &T) -> T {
@@ -151,6 +157,7 @@ impl<T: Atomic> Merge for Option<T> {
 
 #[cfg(test)]
 mod tests {
+    use k8s_openapi::api::core::v1::{PodSpec, PodTemplateSpec};
     use std::collections::{BTreeMap, HashMap};
 
     use super::{merge, Merge};
@@ -425,4 +432,59 @@ mod tests {
             BTreeMap::from([("a", Acc(4)), ("b", Acc(2)), ("c", Acc(5))])
         );
     }
+
+    #[test]
+    fn merge_pod_template_spec() {
+        assert_eq!(
+            merge(
+                PodTemplateSpec {
+                    spec: Some(PodSpec {
+                        service_account_name: Some("my-sa".to_string()),
+                        ..PodSpec::default()
+                    }),
+                    ..PodTemplateSpec::default()
+                },
+                &PodTemplateSpec {
+                    spec: Some(PodSpec {
+                        priority: Some(3000),
+                        ..PodSpec::default()
+                    }),
+                    ..PodTemplateSpec::default()
+                }
+            ),
+            PodTemplateSpec {
+                spec: Some(PodSpec {
+                    service_account_name: Some("my-sa".to_string()),
+                    priority: Some(3000),
+                    ..PodSpec::default()
+                }),
+                ..PodTemplateSpec::default()
+            }
+        );
+        assert_eq!(
+            merge(
+                PodTemplateSpec {
+                    spec: Some(PodSpec {
+                        service_account_name: Some("sa-to-be-overridden".to_string()),
+                        ..PodSpec::default()
+                    }),
+                    ..PodTemplateSpec::default()
+                },
+                &PodTemplateSpec {
+                    spec: Some(PodSpec {
+                        service_account_name: Some("sa-override".to_string()),
+                        ..PodSpec::default()
+                    }),
+                    ..PodTemplateSpec::default()
+                }
+            ),
+            PodTemplateSpec {
+                spec: Some(PodSpec {
+                    service_account_name: Some("sa-override".to_string()),
+                    ..PodSpec::default()
+                }),
+                ..PodTemplateSpec::default()
+            }
+        );
+    }
 }

src/role_utils.rs

@@ -134,7 +134,7 @@ pub struct CommonConfiguration<T> {
 /// Additionally all docs are removed, as the resulting Stackable CRD objects where to big for Kubernetes.
 /// E.g. the HdfsCluster CRD increased to ~3.2 MB (which is over the limit of 3MB), after stripping
 /// the docs it went down to ~1.3 MiB.
-fn pod_overrides_schema(gen: &mut schemars::gen::SchemaGenerator) -> Schema {
+pub fn pod_overrides_schema(gen: &mut schemars::gen::SchemaGenerator) -> Schema {
     let mut schema = PodTemplateSpec::json_schema(gen);
     SimplifyOverrideSchema.visit_schema(&mut schema);
     if let Schema::Object(schema) = &mut schema {