Implement Ephemeral Containers subresource

Extra:

An example of an invalid patch that will not cause an error has been
added to Patch docs.

Signed-off-by: Jessie Chatham Spencer <[email protected]>

Author: jmintb

kube-client/src/api/mod.rs

@@ -14,6 +14,11 @@ mod subresource;
 pub use subresource::{Attach, AttachParams, Execute, Portforward};
 pub use subresource::{Evict, EvictParams, Log, LogParams, ScaleSpec, ScaleStatus};
 
+// Ephemeral containers were stabilized in Kubernetes 1.25.
+k8s_openapi::k8s_if_ge_1_25! {
+    pub use subresource::Ephemeral;
+}
+
 mod util;
 
 pub mod entry;

kube-client/src/api/subresource.rs

@@ -1,6 +1,6 @@
 use bytes::Bytes;
 use futures::Stream;
-use serde::de::DeserializeOwned;
+use serde::{de::DeserializeOwned, Serialize};
 use std::fmt::Debug;
 
 use crate::{
@@ -128,6 +128,160 @@ where
     }
 }
 
+// ----------------------------------------------------------------------------
+// Ephemeral containers
+// ----------------------------------------------------------------------------
+
+/// Marker trait for objects that support the ephemeral containers sub resource.
+pub trait Ephemeral {}
+
+impl Ephemeral for k8s_openapi::api::core::v1::Pod {}
+
+impl<K> Api<K>
+where
+    K: Clone + DeserializeOwned + Ephemeral,
+{
+    /// Replace the ephemeral containers sub resource entirely.
+    ///
+    /// This functions in the same way as [`Api::replace`] except only `.spec.ephemeralcontainers` is replaced, everything else is ignored.
+    ///
+    /// Note that ephemeral containers may **not** be changed or removed once attached to a pod.
+    ///
+    ///
+    /// You way want to patch the underlying resource to gain access to the main container process,
+    /// see the [documentation](https://kubernetes.io/docs/tasks/configure-pod-container/share-process-namespace/) for `sharedProcessNamespace`.
+    ///
+    /// See the Kubernetes [documentation](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/#what-is-an-ephemeral-container) for more details.
+    ///
+    /// [`Api::patch_ephemeral_containers`] may be more ergonomic, as you can will avoid having to first fetch the
+    /// existing subresources with an approriate merge strategy, see the examples for more details.
+    ///
+    /// Example of using `replace_ephemeral_containers`:
+    ///
+    /// ```no_run
+    /// use k8s_openapi::api::core::v1::Pod;
+    /// use kube::{Api, api::PostParams};
+    /// # async fn wrapper() -> Result<(), Box<dyn std::error::Error>> {
+    /// # let client = kube::Client::try_default().await?;
+    /// let pods: Api<Pod> = Api::namespaced(client, "apps");
+    /// let pp = PostParams::default();
+    ///
+    /// // Get pod object with ephemeral containers.
+    /// let mut mypod = pods.get_ephemeral_containers("mypod").await?;
+    ///
+    /// // If there were existing ephemeral containers, we would have to append
+    /// // new containers to the list before calling replace_ephemeral_containers.
+    /// assert_eq!(mypod.spec.as_mut().unwrap().ephemeral_containers, None);
+    ///
+    /// // Add an ephemeral container to the pod object.
+    /// mypod.spec.as_mut().unwrap().ephemeral_containers = Some(serde_json::from_value(serde_json::json!([
+    ///    {
+    ///        "name": "myephemeralcontainer",
+    ///        "image": "busybox:1.34.1",
+    ///        "command": ["sh", "-c", "sleep 20"],
+    ///    },
+    /// ]))?);
+    ///
+    /// pods.replace_ephemeral_containers("mypod", &pp, &mypod).await?;
+    ///
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn replace_ephemeral_containers(&self, name: &str, pp: &PostParams, data: &K) -> Result<K>
+    where
+        K: Serialize,
+    {
+        let mut req = self
+            .request
+            .replace_subresource(
+                "ephemeralcontainers",
+                name,
+                pp,
+                serde_json::to_vec(data).map_err(Error::SerdeError)?,
+            )
+            .map_err(Error::BuildRequest)?;
+        req.extensions_mut().insert("replace_ephemeralcontainers");
+        self.client.request::<K>(req).await
+    }
+
+    /// Patch the ephemeral containers sub resource
+    ///
+    /// Any partial object containing the ephemeral containers
+    /// sub resource is valid as long as the complete structure
+    /// for the object is present, as shown below.
+    ///
+    /// You way want to patch the underlying resource to gain access to the main container process,
+    /// see the [docs](https://kubernetes.io/docs/tasks/configure-pod-container/share-process-namespace/) for `sharedProcessNamespace`.
+    ///
+    /// Ephemeral containers may **not** be changed or removed once attached to a pod.
+    /// Therefore if the chosen merge strategy overwrites the existing ephemeral containers,
+    /// you will have to fetch the existing ephemeral containers first.
+    /// In order to append your new ephemeral containers to the existing list before patching. See some examples and
+    /// discussion related to merge strategies in Kubernetes
+    /// [here](https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/#use-a-json-merge-patch-to-update-a-deployment). The example below uses a strategic merge patch which does not require
+    ///
+    /// See the `Kubernetes` [documentation](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/)
+    /// for more information about ephemeral containers.
+    ///
+    ///
+    /// Example of using `patch_ephemeral_containers`:
+    ///
+    /// ```no_run
+    /// use kube::api::{Api, PatchParams, Patch};
+    /// use k8s_openapi::api::core::v1::Pod;
+    /// # async fn wrapper() -> Result<(), Box<dyn std::error::Error>> {
+    /// # let client = kube::Client::try_default().await?;
+    /// let pods: Api<Pod> = Api::namespaced(client, "apps");
+    /// let pp = PatchParams::default(); // stratetgic merge patch
+    ///
+    /// // Note that the strategic merge patch will concatenate the
+    /// // lists of ephemeral containers so we avoid having to fetch the
+    /// // current list and append to it manually.
+    /// let patch = serde_json::json!({
+    ///    "spec":{
+    ///    "ephemeralContainers": [
+    ///    {
+    ///        "name": "myephemeralcontainer",
+    ///        "image": "busybox:1.34.1",
+    ///        "command": ["sh", "-c", "sleep 20"],
+    ///    },
+    ///    ]
+    /// }});
+    ///
+    /// pods.patch_ephemeral_containers("mypod", &pp, &Patch::Strategic(patch)).await?;
+    ///
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn patch_ephemeral_containers<P: serde::Serialize>(
+        &self,
+        name: &str,
+        pp: &PatchParams,
+        patch: &Patch<P>,
+    ) -> Result<K> {
+        let mut req = self
+            .request
+            .patch_subresource("ephemeralcontainers", name, pp, patch)
+            .map_err(Error::BuildRequest)?;
+
+        req.extensions_mut().insert("patch_ephemeralcontainers");
+        self.client.request::<K>(req).await
+    }
+
+    /// Get the named resource with the ephemeral containers subresource.
+    ///
+    /// This returns the whole K, with metadata and spec.
+    pub async fn get_ephemeral_containers(&self, name: &str) -> Result<K> {
+        let mut req = self
+            .request
+            .get_subresource("ephemeralcontainers", name)
+            .map_err(Error::BuildRequest)?;
+
+        req.extensions_mut().insert("get_ephemeralcontainers");
+        self.client.request::<K>(req).await
+    }
+}
+
 // ----------------------------------------------------------------------------
 
 // TODO: Replace examples with owned custom resources. Bad practice to write to owned objects
@@ -154,23 +308,22 @@ where
     /// NB: Requires that the resource has a status subresource.
     ///
     /// ```no_run
-    /// use kube::{api::{Api, PatchParams, Patch}, Client};
+    /// use kube::api::{Api, PatchParams, Patch};
     /// use k8s_openapi::api::batch::v1::Job;
-    /// #[tokio::main]
-    /// async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    ///     let client = Client::try_default().await?;
-    ///     let jobs: Api<Job> = Api::namespaced(client, "apps");
-    ///     let mut j = jobs.get("baz").await?;
-    ///     let pp = PatchParams::default(); // json merge patch
-    ///     let data = serde_json::json!({
-    ///         "status": {
-    ///             "succeeded": 2
-    ///         }
-    ///     });
-    ///     let o = jobs.patch_status("baz", &pp, &Patch::Merge(data)).await?;
-    ///     assert_eq!(o.status.unwrap().succeeded, Some(2));
-    ///     Ok(())
-    /// }
+    /// # async fn wrapper() -> Result<(), Box<dyn std::error::Error>> {
+    /// # let client = kube::Client::try_default().await?;
+    /// let jobs: Api<Job> = Api::namespaced(client, "apps");
+    /// let mut j = jobs.get("baz").await?;
+    /// let pp = PatchParams::default(); // json merge patch
+    /// let data = serde_json::json!({
+    ///     "status": {
+    ///         "succeeded": 2
+    ///     }
+    /// });
+    /// let o = jobs.patch_status("baz", &pp, &Patch::Merge(data)).await?;
+    /// assert_eq!(o.status.unwrap().succeeded, Some(2));
+    /// # Ok(())
+    /// # }
     /// ```
     pub async fn patch_status<P: serde::Serialize + Debug>(
         &self,
@@ -192,18 +345,17 @@ where
     /// You can leave out the `.spec` entirely from the serialized output.
     ///
     /// ```no_run
-    /// use kube::{api::{Api, PostParams}, Client};
+    /// use kube::api::{Api, PostParams};
     /// use k8s_openapi::api::batch::v1::{Job, JobStatus};
-    /// #[tokio::main]
-    /// async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    ///     let client = Client::try_default().await?;
-    ///     let jobs: Api<Job> = Api::namespaced(client, "apps");
-    ///     let mut o = jobs.get_status("baz").await?; // retrieve partial object
-    ///     o.status = Some(JobStatus::default()); // update the job part
-    ///     let pp = PostParams::default();
-    ///     let o = jobs.replace_status("baz", &pp, serde_json::to_vec(&o)?).await?;
-    ///     Ok(())
-    /// }
+    /// # async fn wrapper() -> Result<(), Box<dyn std::error::Error>> {
+    /// #   let client = kube::Client::try_default().await?;
+    /// let jobs: Api<Job> = Api::namespaced(client, "apps");
+    /// let mut o = jobs.get_status("baz").await?; // retrieve partial object
+    /// o.status = Some(JobStatus::default()); // update the job part
+    /// let pp = PostParams::default();
+    /// let o = jobs.replace_status("baz", &pp, serde_json::to_vec(&o)?).await?;
+    /// #    Ok(())
+    /// # }
     /// ```
     pub async fn replace_status(&self, name: &str, pp: &PostParams, data: Vec<u8>) -> Result<K> {
         let mut req = self