Implement client native object reference fetching (#1511)

Implement native object reference fetching

Signed-off-by: Danil-Grigorev <danil.grigorev@suse.com>

kube-client/src/client/client_ext.rs

@@ -1,10 +1,13 @@
 use crate::{Client, Error, Result};
-use k8s_openapi::api::core::v1::Namespace as k8sNs;
+use k8s_openapi::{
+    api::core::v1::{LocalObjectReference, Namespace as k8sNs, ObjectReference},
+    apimachinery::pkg::apis::meta::v1::OwnerReference,
+};
 use kube_core::{
     object::ObjectList,
     params::{GetParams, ListParams},
     request::Request,
-    ClusterResourceScope, DynamicResourceScope, NamespaceResourceScope, Resource,
+    ApiResource, ClusterResourceScope, DynamicResourceScope, NamespaceResourceScope, Resource,
 };
 use serde::{de::DeserializeOwned, Serialize};
 use std::fmt::Debug;
@@ -42,9 +45,109 @@ pub struct Cluster;
 /// You can create this directly, or convert `From` a `String` / `&str`, or `TryFrom` an `k8s_openapi::api::core::v1::Namespace`
 pub struct Namespace(String);
 
+/// Referenced object name resolution
+pub trait ObjectRef<K>: ObjectUrl<K> {
+    fn name(&self) -> Option<&str>;
+}
+
+/// Reference resolver for a specified namespace
+pub trait NamespacedRef<K> {
+    /// Resolve reference in the provided namespace
+    fn within(&self, namespace: impl Into<Option<String>>) -> impl ObjectRef<K>;
+}
+
+impl<K> ObjectUrl<K> for ObjectReference
+where
+    K: Resource,
+{
+    fn url_path(&self) -> String {
+        url_path(
+            &ApiResource::from_gvk(&self.clone().into()),
+            self.namespace.clone(),
+        )
+    }
+}
+
+impl<K> ObjectRef<K> for ObjectReference
+where
+    K: Resource,
+{
+    fn name(&self) -> Option<&str> {
+        self.name.as_deref()
+    }
+}
+
+impl<K> NamespacedRef<K> for ObjectReference
+where
+    K: Resource,
+    K::Scope: NamespaceScope,
+{
+    fn within(&self, namespace: impl Into<Option<String>>) -> impl ObjectRef<K> {
+        Self {
+            namespace: namespace.into(),
+            ..self.clone()
+        }
+    }
+}
+
+impl<K> ObjectUrl<K> for OwnerReference
+where
+    K: Resource,
+    K::Scope: ClusterScope,
+{
+    fn url_path(&self) -> String {
+        url_path(&ApiResource::from_gvk(&self.clone().into()), None)
+    }
+}
+
+impl<K> ObjectRef<K> for OwnerReference
+where
+    K: Resource,
+    K::Scope: ClusterScope,
+{
+    fn name(&self) -> Option<&str> {
+        self.name.as_str().into()
+    }
+}
+
+impl<K> NamespacedRef<K> for OwnerReference
+where
+    K: Resource,
+    K::Scope: NamespaceScope,
+{
+    fn within(&self, namespace: impl Into<Option<String>>) -> impl ObjectRef<K> {
+        ObjectReference {
+            api_version: self.api_version.clone().into(),
+            namespace: namespace.into(),
+            name: self.name.clone().into(),
+            uid: self.uid.clone().into(),
+            kind: self.kind.clone().into(),
+            ..Default::default()
+        }
+    }
+}
+
+impl<K> NamespacedRef<K> for LocalObjectReference
+where
+    K: Resource,
+    K::DynamicType: Default,
+    K::Scope: NamespaceScope,
+{
+    fn within(&self, namespace: impl Into<Option<String>>) -> impl ObjectRef<K> {
+        let dt = Default::default();
+        ObjectReference {
+            api_version: K::api_version(&dt).to_string().into(),
+            namespace: namespace.into(),
+            name: self.name.clone(),
+            kind: K::kind(&dt).to_string().into(),
+            ..Default::default()
+        }
+    }
+}
+
 /// Scopes for `unstable-client` [`Client#impl-Client`] extension methods
 pub mod scope {
-    pub use super::{Cluster, Namespace};
+    pub use super::{Cluster, Namespace, NamespacedRef};
 }
 
 // All objects can be listed cluster-wide
@@ -184,6 +287,69 @@ impl Client {
         self.request::<K>(req).await
     }
 
+    /// Fetch a single instance of a `Resource` from a provided object reference.
+    ///
+    /// ```no_run
+    /// # use k8s_openapi::api::rbac::v1::ClusterRole;
+    /// # use k8s_openapi::api::core::v1::Service;
+    /// # use k8s_openapi::api::core::v1::Secret;
+    /// # use k8s_openapi::api::core::v1::ObjectReference;
+    /// # use k8s_openapi::api::core::v1::LocalObjectReference;
+    /// # use k8s_openapi::api::core::v1::{Node, Pod};
+    /// # use kube::{Resource, ResourceExt, api::GetParams};
+    /// # use kube::client::scope::NamespacedRef;
+    /// # use kube::api::DynamicObject;
+    /// # async fn wrapper() -> Result<(), Box<dyn std::error::Error>> {
+    /// # let client: kube::Client = todo!();
+    /// // cluster scoped
+    /// let cr: ClusterRole = todo!();
+    /// let cr: ClusterRole = client.fetch(&cr.object_ref(&())).await?;
+    /// assert_eq!(cr.name_unchecked(), "cluster-admin");
+    /// // namespace scoped
+    /// let svc: Service = todo!();
+    /// let svc: Service = client.fetch(&svc.object_ref(&())).await?;
+    /// assert_eq!(svc.name_unchecked(), "kubernetes");
+    /// // Fetch an owner of the resource
+    /// let pod: Pod = todo!();
+    /// let owner = pod
+    ///     .owner_references()
+    ///     .to_vec()
+    ///     .into_iter()
+    ///     .find(|r| r.kind == Node::kind(&()))
+    ///     .ok_or("Not Found")?;
+    /// let node: Node = client.fetch(&owner).await?;
+    /// // Namespace scoped objects require namespace
+    /// let pod: Pod = client.fetch(&owner.within("ns".to_string())).await?;
+    /// // Fetch dynamic object to resolve type later
+    /// let dynamic: DynamicObject = client.fetch(&owner.within("ns".to_string())).await?;
+    /// // Fetch using local object reference
+    /// let secret_ref = pod
+    ///     .spec
+    ///     .unwrap_or_default()
+    ///     .image_pull_secrets
+    ///     .unwrap_or_default()
+    ///     .get(0)
+    ///     .unwrap_or(&LocalObjectReference{name: Some("pull_secret".into())});
+    /// let secret: Secret = client.fetch(&secret_ref.within(pod.namespace())).await?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn fetch<K>(&self, reference: &impl ObjectRef<K>) -> Result<K>
+    where
+        K: Resource + Serialize + DeserializeOwned + Clone + Debug,
+    {
+        let mut req = Request::new(reference.url_path())
+            .get(
+                reference
+                    .name()
+                    .ok_or(Error::RefResolve("Reference is empty".to_string()))?,
+                &GetParams::default(),
+            )
+            .map_err(Error::BuildRequest)?;
+        req.extensions_mut().insert("get");
+        self.request::<K>(req).await
+    }
+
     /// List instances of a `Resource` implementing type `K` at the specified scope.
     ///
     /// ```no_run
@@ -216,13 +382,32 @@ impl Client {
     }
 }
 
+// Resource url_path resolver
+fn url_path(r: &ApiResource, namespace: Option<String>) -> String {
+    let n = if let Some(ns) = namespace {
+        format!("namespaces/{ns}/")
+    } else {
+        "".into()
+    };
+    format!(
+        "/{group}/{api_version}/{namespaces}{plural}",
+        group = if r.group.is_empty() { "api" } else { "apis" },
+        api_version = r.api_version,
+        namespaces = n,
+        plural = r.plural
+    )
+}
+
 #[cfg(test)]
 mod test {
+    use crate::client::client_ext::NamespacedRef;
+
     use super::{
         scope::{Cluster, Namespace},
         Client, ListParams,
     };
-    use kube_core::ResourceExt;
+    use k8s_openapi::api::core::v1::LocalObjectReference;
+    use kube_core::{DynamicObject, Resource, ResourceExt};
 
     #[tokio::test]
     #[ignore = "needs cluster (will list/get namespaces, pods, jobs, svcs, clusterroles)"]
@@ -256,4 +441,100 @@ mod test {
 
         Ok(())
     }
+
+    #[tokio::test]
+    #[ignore = "needs cluster (will get svcs, clusterroles, pods, nodes)"]
+    async fn client_ext_fetch_ref_pods_svcs() -> Result<(), Box<dyn std::error::Error>> {
+        use k8s_openapi::api::{
+            core::v1::{Node, ObjectReference, Pod, Service},
+            rbac::v1::ClusterRole,
+        };
+
+        let client = Client::try_default().await?;
+        // namespaced fetch
+        let svc: Service = client
+            .fetch(&ObjectReference {
+                kind: Some(Service::kind(&()).into()),
+                api_version: Some(Service::api_version(&()).into()),
+                name: Some("kubernetes".into()),
+                namespace: Some("default".into()),
+                ..Default::default()
+            })
+            .await?;
+        assert_eq!(svc.name_unchecked(), "kubernetes");
+        // global fetch
+        let ca: ClusterRole = client
+            .fetch(&ObjectReference {
+                kind: Some(ClusterRole::kind(&()).into()),
+                api_version: Some(ClusterRole::api_version(&()).into()),
+                name: Some("cluster-admin".into()),
+                ..Default::default()
+            })
+            .await?;
+        assert_eq!(ca.name_unchecked(), "cluster-admin");
+        // namespaced fetch untyped
+        let svc: DynamicObject = client.fetch(&svc.object_ref(&())).await?;
+        assert_eq!(svc.name_unchecked(), "kubernetes");
+        // global fetch untyped
+        let ca: DynamicObject = client.fetch(&ca.object_ref(&())).await?;
+        assert_eq!(ca.name_unchecked(), "cluster-admin");
+
+        // Fetch using local object reference
+        let svc: Service = client
+            .fetch(
+                &LocalObjectReference {
+                    name: svc.name_any().into(),
+                }
+                .within(svc.namespace()),
+            )
+            .await?;
+        assert_eq!(svc.name_unchecked(), "kubernetes");
+
+        let kube_system: Namespace = "kube-system".into();
+        for pod in client
+            .list::<Pod>(
+                &ListParams::default().labels("component=kube-apiserver"),
+                &kube_system,
+            )
+            .await?
+        {
+            let owner = pod
+                .owner_references()
+                .to_vec()
+                .into_iter()
+                .find(|r| r.kind == Node::kind(&()))
+                .ok_or("Not found")?;
+            let _: Node = client.fetch(&owner).await?;
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    #[ignore = "needs cluster (will get svcs, clusterroles, pods, nodes)"]
+    async fn fetch_fails() -> Result<(), Box<dyn std::error::Error>> {
+        use crate::error::Error;
+        use k8s_openapi::api::core::v1::{ObjectReference, Pod, Service};
+
+        let client = Client::try_default().await?;
+        // namespaced fetch
+        let svc: Service = client
+            .fetch(&ObjectReference {
+                kind: Some(Service::kind(&()).into()),
+                api_version: Some(Service::api_version(&()).into()),
+                name: Some("kubernetes".into()),
+                namespace: Some("default".into()),
+                ..Default::default()
+            })
+            .await?;
+        let err = client.fetch::<Pod>(&svc.object_ref(&())).await.unwrap_err();
+        assert!(matches!(err, Error::SerdeError(_)));
+        assert_eq!(err.to_string(), "Error deserializing response: invalid value: string \"Service\", expected Pod at line 1 column 17".to_string());
+
+        let obj: DynamicObject = client.fetch(&svc.object_ref(&())).await?;
+        let err = obj.try_parse::<Pod>().unwrap_err();
+        assert_eq!(err.to_string(), "failed to parse this DynamicObject into a Resource: invalid value: string \"Service\", expected Pod".to_string());
+
+        Ok(())
+    }
 }

kube-client/src/error.rs

@@ -86,6 +86,12 @@ pub enum Error {
     #[cfg_attr(docsrs, doc(cfg(feature = "client")))]
     #[error("auth error: {0}")]
     Auth(#[source] crate::client::AuthError),
+
+    /// Error resolving resource reference
+    #[cfg(feature = "unstable-client")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "unstable-client")))]
+    #[error("Reference resolve error: {0}")]
+    RefResolve(String),
 }
 
 #[derive(Error, Debug)]

kube-core/src/gvk.rs

@@ -2,6 +2,7 @@
 use std::str::FromStr;
 
 use crate::TypeMeta;
+use k8s_openapi::{api::core::v1::ObjectReference, apimachinery::pkg::apis::meta::v1::OwnerReference};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -47,6 +48,35 @@ impl TryFrom<TypeMeta> for GroupVersionKind {
     }
 }
 
+impl From<OwnerReference> for GroupVersionKind {
+    fn from(value: OwnerReference) -> Self {
+        let (group, version) = match value.api_version.split_once("/") {
+            Some((group, version)) => (group, version),
+            None => ("", value.api_version.as_str()),
+        };
+        Self {
+            group: group.into(),
+            version: version.into(),
+            kind: value.kind,
+        }
+    }
+}
+
+impl From<ObjectReference> for GroupVersionKind {
+    fn from(value: ObjectReference) -> Self {
+        let api_version = value.api_version.unwrap_or_default();
+        let (group, version) = match api_version.split_once("/") {
+            Some((group, version)) => (group, version),
+            None => ("", api_version.as_str()),
+        };
+        Self {
+            group: group.into(),
+            version: version.into(),
+            kind: value.kind.unwrap_or_default(),
+        }
+    }
+}
+
 /// Core information about a family of API Resources
 #[derive(Deserialize, Serialize, Debug, Clone, PartialEq, Eq, Hash)]
 pub struct GroupVersion {