Use TryInto when validating settings, not evaluating

When evaluating, just unwrap the result, since we don't have to take a
decision based on that. We know that settings are valid given that
they were already validated with `validate_settings`. Just unwrap the
result on the real evaluation.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "selinux-psp"
-version = "0.1.2"
+version = "0.1.3"
 authors = ["Rafael Fernández López <[email protected]>"]
 edition = "2018"
 

src/lib.rs

@@ -29,10 +29,9 @@ enum PolicyResponse {
 fn validate(payload: &[u8]) -> CallResult {
     let validation_request: ValidationRequest<ExternalSettings> = ValidationRequest::new(payload)?;
 
-    let settings: Settings = match validation_request.settings.try_into() {
-        Ok(settings) => settings,
-        Err(err) => return kubewarden::reject_request(Some(err.to_string()), None),
-    };
+    // It is safe to unwrap here, because the validate_settings function already made sure that
+    // ExternalSettings can be converted to Settings.
+    let settings: Settings = validation_request.settings.try_into().unwrap();
 
     let pod = match serde_json::from_value::<apicore::Pod>(validation_request.request.object) {
         Ok(pod) => pod,

src/settings.rs

@@ -7,7 +7,7 @@ use std::{
 
 use k8s_openapi::api::core::v1 as apicore;
 
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Clone, Serialize, Deserialize, Debug)]
 pub(crate) struct SELinuxOptionsExternal {
     user: Option<String>,
     role: Option<String>,
@@ -95,7 +95,7 @@ impl SELinuxLevel {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Clone, Serialize, Deserialize, Debug)]
 #[serde(tag = "rule", deny_unknown_fields)]
 pub(crate) enum ExternalSettings {
     MustRunAs(SELinuxOptionsExternal),
@@ -141,6 +141,9 @@ impl kubewarden::settings::Validatable for ExternalSettings {
                             .to_string(),
                     );
                 }
+                if let Err(err) = TryInto::<Settings>::try_into(self.clone()) {
+                    return Err(format!("settings are invalid: {}", err));
+                }
                 Ok(())
             }
         }