Add an in-between mode where schema is still used but not derived

Signed-off-by: Teo Klestrup Röijezon <[email protected]>

Author: nightkr

CHANGELOG.md

@@ -12,8 +12,8 @@ UNRELEASED
    - Replaced `kube::Error::RequestValidation(String)` variant with `kube::Error::BuildRequest(kube::core::request::Error)`. This variant includes possible errors when building an HTTP request as described above, and contains errors that was previously grouped under `kube::Error::SerdeError` and `kube::Error::HttpError`.
    - Removed `impl From<T> for kube::Error` for the following types: `std::io::Error`, `hyper::Error`, `tower::BoxError`, `std::string::FromUtf8Error`, `http::Error`, `http::uri::InvalidUri`, `serde_json::Error`, `openssl::error::ErrorStack`, `kube::core::Error`, `kube::error::ConfigError`, `kube::error::DisoveryError`, `kube::error::OAuthError`.
    - Changed variants of error enums in `kube::runtime`. Replaced `snafu` with `thiserror`.
- * BREAKING: Replaced feature `kube-runtime/schema` with attribute `#[kube(derive_schema)]` - #690
-   - If you currently disable default `kube-runtime` default features to avoid this issue, add `#[kube(derive_schema = false)]` to your spec struct instead
+ * BREAKING: Replaced feature `kube-runtime/schema` with attribute `#[kube(schema_mode)]` - #690
+   - If you currently disable default `kube-runtime` default features to avoid automatic schema generation, add `#[kube(schema_mode = "disabled")]` to your spec struct instead
 
 0.63.2 / 2021-10-28
 ===================

examples/crd_derive_no_schema.rs

@@ -14,7 +14,7 @@ use serde::{Deserialize, Serialize};
     version = "v1",
     kind = "Bar",
     namespaced,
-    derive_schema = false
+    schema_mode = "disabled"
 )]
 pub struct MyBar {
     bars: u32,

kube-derive/src/custom_resource.rs

@@ -1,4 +1,4 @@
-use darling::FromDeriveInput;
+use darling::{FromDeriveInput, FromMeta};
 use proc_macro2::{Ident, Span, TokenStream};
 use syn::{parse_quote, Data, DeriveInput, Path, Visibility};
 
@@ -24,7 +24,7 @@ struct KubeAttrs {
     #[darling(multiple, rename = "derive")]
     derives: Vec<String>,
     #[darling(default)]
-    derive_schema: Option<bool>,
+    schema_mode: Option<SchemaMode>,
     #[darling(default)]
     status: Option<String>,
     #[darling(multiple, rename = "category")]
@@ -66,6 +66,42 @@ fn default_serde_json() -> Path {
     parse_quote! { ::serde_json }
 }
 
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+enum SchemaMode {
+    Disabled,
+    Custom,
+    Derived,
+}
+
+impl SchemaMode {
+    fn derive(self) -> bool {
+        match self {
+            SchemaMode::Disabled => false,
+            SchemaMode::Custom => false,
+            SchemaMode::Derived => true,
+        }
+    }
+
+    fn use_in_crd(self) -> bool {
+        match self {
+            SchemaMode::Disabled => false,
+            SchemaMode::Custom => true,
+            SchemaMode::Derived => true,
+        }
+    }
+}
+
+impl FromMeta for SchemaMode {
+    fn from_string(value: &str) -> darling::Result<Self> {
+        match value {
+            "disabled" => Ok(SchemaMode::Disabled),
+            "custom" => Ok(SchemaMode::Custom),
+            "derived" => Ok(SchemaMode::Derived),
+            x => Err(darling::Error::unknown_value(x)),
+        }
+    }
+}
+
 pub(crate) fn derive(input: proc_macro2::TokenStream) -> proc_macro2::TokenStream {
     let derive_input: DeriveInput = match syn::parse2(input) {
         Err(err) => return err.to_compile_error(),
@@ -94,7 +130,7 @@ pub(crate) fn derive(input: proc_macro2::TokenStream) -> proc_macro2::TokenStrea
         version,
         namespaced,
         derives,
-        derive_schema,
+        schema_mode,
         status,
         plural,
         singular,
@@ -156,16 +192,20 @@ pub(crate) fn derive(input: proc_macro2::TokenStream) -> proc_macro2::TokenStrea
     }
 
     // Enable schema generation by default for v1 because it's mandatory.
-    let schema_gen_enabled = derive_schema.unwrap_or(apiextensions == "v1");
+    let schema_mode = schema_mode.unwrap_or(if apiextensions == "v1" {
+        SchemaMode::Derived
+    } else {
+        SchemaMode::Disabled
+    });
     // We exclude fields `apiVersion`, `kind`, and `metadata` from our schema because
     // these are validated by the API server implicitly. Also, we can't generate the
     // schema for `metadata` (`ObjectMeta`) because it doesn't implement `JsonSchema`.
-    let schemars_skip = if schema_gen_enabled {
+    let schemars_skip = if schema_mode.derive() {
         quote! { #[schemars(skip)] }
     } else {
         quote! {}
     };
-    if schema_gen_enabled {
+    if schema_mode.derive() {
         derive_paths.push(syn::parse_quote! { #schemars::JsonSchema });
     }
 
@@ -291,7 +331,7 @@ pub(crate) fn derive(input: proc_macro2::TokenStream) -> proc_macro2::TokenStrea
     let crd_meta_name = format!("{}.{}", plural, group);
     let crd_meta = quote! { { "name": #crd_meta_name } };
 
-    let schemagen = if schema_gen_enabled {
+    let schemagen = if schema_mode.use_in_crd() {
         quote! {
             // Don't use definitions and don't include `$schema` because these are not allowed.
             let gen = #schemars::gen::SchemaSettings::openapi3().with(|s| {

kube-derive/src/lib.rs

@@ -111,12 +111,22 @@ mod custom_resource;
 /// Adding `#[kube(derive = "PartialEq")]` is required if you want your generated
 /// top level type to be able to `#[derive(PartialEq)]`
 ///
-/// ### `#[kube(derive_schema = false)]`
-/// Disables the automatic `#[derive(JsonSchema)]` on the top level generated type.
+/// ### `#[kube(schema_mode = "mode")]`
+/// Defines whether the `JsonSchema` of the top level generated type should be used when generating a `CustomResourceDefinition`.
 ///
-/// This can be used to provide a completely custom schema, or to interact with third-party custom resources,
+/// Legal values:
+/// - `"derived"`: A `JsonSchema` implementation is automatically derived
+/// - `"custom"`: `JsonSchema` is not derived, but used when creating the `CustomResource` object
+/// - `"disabled"`: No `JsonSchema` is used
+///
+/// This can be used to provide a completely custom schema, or to interact with third-party custom resources
 /// where you are not responsible for installing the `CustomResourceDefinition`.
 ///
+/// Defaults to `"disabled"` when `apiextensions = "v1beta1"`, otherwise `"derived"`.
+///
+/// NOTE: `apiextensions = "v1"` `CustomResourceDefinition`s require a schema. If `schema_mode = "disabled"` then
+/// `Self::crd()` will not be installable into the cluster as-is.
+///
 /// ### `#[kube(scale = r#"json"#)]`
 /// Allow customizing the scale struct for the [scale subresource](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#subresources).
 ///