Add support for CRD ConversionReview types (#999)

* Add conversion webhook typings

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Add simple test

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Fix formatting

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Improve docs

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Add is_success & is_failure methods

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Use our Status in admission

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Expand test

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Rename response methods

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Avoid optionality

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Move some code around

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Fix copy-paste error

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Improve response signatures

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

* Change status in invalid admission response

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>

Signed-off-by: Mikail Bagishov <bagishov.mikail@yandex.ru>
Co-authored-by: Eirik A <sszynrae@gmail.com>

kube-client/src/lib.rs

@@ -137,7 +137,10 @@ mod test {
     };
     use futures::{StreamExt, TryStreamExt};
     use k8s_openapi::api::core::v1::Pod;
-    use kube_core::params::{DeleteParams, Patch};
+    use kube_core::{
+        params::{DeleteParams, Patch},
+        response::StatusSummary,
+    };
     use serde_json::json;
     use tower::ServiceBuilder;
 
@@ -475,7 +478,7 @@ mod test {
         let ep = EvictParams::default();
         let eres = pods.evict("busybox-kube3", &ep).await?;
         assert_eq!(eres.code, 201); // created
-        assert_eq!(eres.status, "Success");
+        assert!(eres.is_success());
 
         Ok(())
     }

kube-core/src/admission.rs

@@ -10,14 +10,12 @@ use crate::{
     gvk::{GroupVersionKind, GroupVersionResource},
     metadata::TypeMeta,
     resource::Resource,
+    Status,
 };
 
 use std::collections::HashMap;
 
-use k8s_openapi::{
-    api::authentication::v1::UserInfo,
-    apimachinery::pkg::{apis::meta::v1::Status, runtime::RawExtension},
-};
+use k8s_openapi::{api::authentication::v1::UserInfo, apimachinery::pkg::runtime::RawExtension};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -307,10 +305,7 @@ impl AdmissionResponse {
             },
             uid: Default::default(),
             allowed: false,
-            result: Status {
-                reason: Some(reason.to_string()),
-                ..Default::default()
-            },
+            result: Status::failure(&reason.to_string(), "InvalidRequest"),
             patch: None,
             patch_type: None,
             audit_annotations: Default::default(),
@@ -322,7 +317,7 @@ impl AdmissionResponse {
     #[must_use]
     pub fn deny<T: ToString>(mut self, reason: T) -> Self {
         self.allowed = false;
-        self.result.message = Some(reason.to_string());
+        self.result.message = reason.to_string();
         self
     }
 

kube-core/src/conversion/mod.rs

@@ -0,0 +1,8 @@
+//! Contains types useful for implementing custom resource conversion webhooks.
+
+pub use self::types::{
+    ConversionRequest, ConversionResponse, ConversionReview, ConvertConversionReviewError,
+};
+
+/// Defines low-level typings.
+mod types;

kube-core/src/conversion/test_data/simple.json

@@ -0,0 +1,55 @@
+{
+    "kind": "ConversionReview",
+    "apiVersion": "apiextensions.k8s.io/v1",
+    "request": {
+        "uid": "f263987e-4d58-465a-9195-bf72a1c83623",
+        "desiredAPIVersion": "nullable.se/v1",
+        "objects": [
+            {
+                "apiVersion": "nullable.se/v2",
+                "kind": "ConfigMapGenerator",
+                "metadata": {
+                    "annotations": {
+                        "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"nullable.se/v2\",\"kind\":\"ConfigMapGenerator\",\"metadata\":{\"annotations\":{},\"name\":\"kek\",\"namespace\":\"default\"},\"spec\":{\"content\":\"x\"}}\n"
+                    },
+                    "creationTimestamp": "2022-09-04T14:21:34Z",
+                    "generation": 1,
+                    "managedFields": [
+                        {
+                            "apiVersion": "nullable.se/v2",
+                            "fieldsType": "FieldsV1",
+                            "fieldsV1": {
+                                "f:metadata": {
+                                    "f:annotations": {
+                                        ".": {},
+                                        "f:kubectl.kubernetes.io/last-applied-configuration": {}
+                                    }
+                                },
+                                "f:spec": {
+                                    ".": {},
+                                    "f:content": {}
+                                }
+                            },
+                            "manager": "kubectl-client-side-apply",
+                            "operation": "Update",
+                            "time": "2022-09-04T14:21:34Z"
+                        }
+                    ],
+                    "name": "kek",
+                    "namespace": "default",
+                    "uid": "af7e84e4-573e-4b6e-bb66-0ea578c740da"
+                },
+                "spec": {
+                    "content": "x"
+                }
+            }
+        ]
+    },
+    "response": {
+        "uid": "",
+        "convertedObjects": null,
+        "result": {
+            "metadata": {}
+        }
+    }
+}

kube-core/src/conversion/types.rs

@@ -0,0 +1,212 @@
+use crate::{Status, TypeMeta};
+use serde::{Deserialize, Deserializer, Serialize};
+use thiserror::Error;
+
+/// The `kind` field in [`TypeMeta`]
+pub const META_KIND: &str = "ConversionReview";
+/// The `api_version` field in [`TypeMeta`] on the v1 version
+pub const META_API_VERSION_V1: &str = "apiextensions.k8s.io/v1";
+
+#[derive(Debug, Error)]
+#[error("request missing in ConversionReview")]
+/// Returned when `ConversionReview` cannot be converted into `ConversionRequest`
+pub struct ConvertConversionReviewError;
+
+/// Struct that describes both request and response
+#[derive(Serialize, Deserialize)]
+pub struct ConversionReview {
+    /// Contains the API version and type of the request
+    #[serde(flatten)]
+    pub types: TypeMeta,
+    /// Contains conversion request
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub request: Option<ConversionRequest>,
+    /// Contains conversion response
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(default)]
+    pub response: Option<ConversionResponse>,
+}
+
+/// Part of ConversionReview which is set on input (i.e. generated by apiserver)
+#[derive(Serialize, Deserialize)]
+pub struct ConversionRequest {
+    /// [`TypeMeta`] of the [`ConversionReview`] this response was created from
+    ///  
+    /// This field dopied from the corresponding [`ConversionReview`].
+    /// It is not part of the Kubernetes API, it's consumed only by `kube`.
+    #[serde(skip)]
+    pub types: Option<TypeMeta>,
+    /// Random uid uniquely identifying this conversion call
+    pub uid: String,
+    /// The API group and version the objects should be converted to
+    #[serde(rename = "desiredAPIVersion")]
+    pub desired_api_version: String,
+    /// The list of objects to convert
+    ///
+    /// Note that list may contain one or more objects, in one or more versions.
+    // This field uses raw Value instead of Object/DynamicObject to simplify
+    // further downcasting.
+    pub objects: Vec<serde_json::Value>,
+}
+
+impl ConversionRequest {
+    /// Extracts request from the [`ConversionReview`]
+    pub fn from_review(review: ConversionReview) -> Result<Self, ConvertConversionReviewError> {
+        ConversionRequest::try_from(review)
+    }
+}
+
+impl TryFrom<ConversionReview> for ConversionRequest {
+    type Error = ConvertConversionReviewError;
+
+    fn try_from(review: ConversionReview) -> Result<Self, Self::Error> {
+        match review.request {
+            Some(mut req) => {
+                req.types = Some(review.types);
+                Ok(req)
+            }
+            None => Err(ConvertConversionReviewError),
+        }
+    }
+}
+
+/// Part of ConversionReview which is set on output (i.e. generated by conversion webhook)
+#[derive(Serialize, Deserialize)]
+pub struct ConversionResponse {
+    /// [`TypeMeta`] of the [`ConversionReview`] this response was derived from
+    ///  
+    /// This field is copied from the corresponding [`ConversionRequest`].
+    /// It is not part of the Kubernetes API, it's consumed only by `kube`.
+    #[serde(skip)]
+    pub types: Option<TypeMeta>,
+    /// Copy of .request.uid
+    pub uid: String,
+    /// Outcome of the conversion operation
+    ///
+    /// Success: all objects were successfully converted
+    /// Failure: at least one object could not be converted.
+    /// It is recommended that conversion fails as rare as possible.
+    pub result: Status,
+    /// Converted objects
+    ///
+    /// This field should contain objects in the same order as in the request
+    /// Should be empty if conversion failed.
+    #[serde(rename = "convertedObjects")]
+    #[serde(deserialize_with = "parse_converted_objects")]
+    pub converted_objects: Vec<serde_json::Value>,
+}
+
+fn parse_converted_objects<'de, D>(de: D) -> Result<Vec<serde_json::Value>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    #[derive(Deserialize)]
+    #[serde(untagged)]
+    enum Helper {
+        List(Vec<serde_json::Value>),
+        Null(()),
+    }
+
+    let h: Helper = Helper::deserialize(de)?;
+    let res = match h {
+        Helper::List(l) => l,
+        Helper::Null(()) => Vec::new(),
+    };
+    Ok(res)
+}
+
+impl ConversionResponse {
+    /// Creates a new response, matching provided request
+    ///
+    /// This response must be finalized with one of:
+    /// - [`ConversionResponse::success`] when conversion succeeded
+    /// - [`ConversionResponse::failure`] when conversion failed
+    pub fn for_request(request: ConversionRequest) -> Self {
+        ConversionResponse::from(request)
+    }
+
+    /// Creates successful conversion response
+    ///
+    /// `converted_objects` must specify objects in the exact same order as on input.
+    pub fn success(mut self, converted_objects: Vec<serde_json::Value>) -> Self {
+        self.result = Status::success();
+        self.converted_objects = converted_objects;
+        self
+    }
+
+    /// Creates failed conversion response (discouraged)
+    ///
+    /// `request_uid` must be equal to the `.uid` field in the request.
+    /// `message` and `reason` will be returned to the apiserver.
+    pub fn failure(mut self, status: Status) -> Self {
+        self.result = status;
+        self
+    }
+
+    /// Creates failed conversion response, not matched with any request
+    ///
+    /// You should only call this function when request couldn't be parsed into [`ConversionRequest`].
+    /// Otherwise use `error`.
+    pub fn invalid(status: Status) -> Self {
+        ConversionResponse {
+            types: None,
+            uid: String::new(),
+            result: status,
+            converted_objects: Vec::new(),
+        }
+    }
+
+    /// Converts response into a [`ConversionReview`] value, ready to be sent as a response
+    pub fn into_review(self) -> ConversionReview {
+        self.into()
+    }
+}
+
+impl From<ConversionRequest> for ConversionResponse {
+    fn from(request: ConversionRequest) -> Self {
+        ConversionResponse {
+            types: request.types,
+            uid: request.uid,
+            result: Status {
+                status: None,
+                code: 0,
+                message: String::new(),
+                reason: String::new(),
+                details: None,
+            },
+            converted_objects: Vec::new(),
+        }
+    }
+}
+
+impl From<ConversionResponse> for ConversionReview {
+    fn from(mut response: ConversionResponse) -> Self {
+        ConversionReview {
+            types: response.types.take().unwrap_or_else(|| {
+                // we don't know which uid, apiVersion and kind to use, let's just use something
+                TypeMeta {
+                    api_version: META_API_VERSION_V1.to_string(),
+                    kind: META_KIND.to_string(),
+                }
+            }),
+            request: None,
+            response: Some(response),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{ConversionRequest, ConversionResponse};
+
+    #[test]
+    fn simple_request_parses() {
+        // this file contains dump of real request generated by kubernetes v1.22
+        let data = include_str!("./test_data/simple.json");
+        // check that we can parse this review, and all chain of conversion worls
+        let review = serde_json::from_str(data).unwrap();
+        let req = ConversionRequest::from_review(review).unwrap();
+        let res = ConversionResponse::for_request(req);
+        let _ = res.into_review();
+    }
+}

kube-core/src/lib.rs

@@ -14,6 +14,8 @@
 #[cfg(feature = "admission")]
 pub mod admission;
 
+pub mod conversion;
+
 pub mod discovery;
 
 pub mod dynamic;