Add managed_fields accessors to ResourceExt (#898)

Signed-off-by: clux <sszynrae@gmail.com>

kube-core/src/resource.rs

@@ -1,5 +1,8 @@
 pub use k8s_openapi::apimachinery::pkg::apis::meta::v1::ObjectMeta;
-use k8s_openapi::{api::core::v1::ObjectReference, apimachinery::pkg::apis::meta::v1::OwnerReference};
+use k8s_openapi::{
+    api::core::v1::ObjectReference,
+    apimachinery::pkg::apis::meta::v1::{ManagedFieldsEntry, OwnerReference},
+};
 use std::{borrow::Cow, collections::BTreeMap};
 
 /// An accessor trait for a kubernetes Resource.
@@ -170,6 +173,10 @@ pub trait ResourceExt: Resource {
     fn finalizers(&self) -> &[String];
     /// Provides mutable access to the finalizers
     fn finalizers_mut(&mut self) -> &mut Vec<String>;
+    /// Returns managed fields
+    fn managed_fields(&self) -> &[ManagedFieldsEntry];
+    /// Provides mutable access to managed fields
+    fn managed_fields_mut(&mut self) -> &mut Vec<ManagedFieldsEntry>;
 }
 
 // TODO: replace with ordinary static when BTreeMap::new() is no longer
@@ -225,4 +232,12 @@ impl<K: Resource> ResourceExt for K {
     fn finalizers_mut(&mut self) -> &mut Vec<String> {
         self.meta_mut().finalizers.get_or_insert_with(Vec::new)
     }
+
+    fn managed_fields(&self) -> &[ManagedFieldsEntry] {
+        self.meta().managed_fields.as_deref().unwrap_or_default()
+    }
+
+    fn managed_fields_mut(&mut self) -> &mut Vec<ManagedFieldsEntry> {
+        self.meta_mut().managed_fields.get_or_insert_with(Vec::new)
+    }
 }

kube/src/lib.rs

@@ -339,6 +339,7 @@ mod test {
                 .entry("kube.rs".to_string())
                 .or_insert_with(|| "hello".to_string());
             pod.finalizers_mut().push("kube-finalizer".to_string());
+            pod.managed_fields_mut().clear();
             // NB: we are **not** pushing these back upstream - (Api::apply or Api::replace needed for it)
         }
         // check we can iterate over ObjectList normally - and check the mutations worked
@@ -347,6 +348,7 @@ mod test {
             assert!(pod.labels().get("kube.rs").is_some());
             assert!(pod.finalizers().contains(&"kube-finalizer".to_string()));
             assert!(pod.spec().containers.is_empty());
+            assert!(pod.managed_fields().is_empty());
         }
         Ok(())
     }