Initial Entry API sketch

Fixes #810

kube-client/src/api/entry.rs

@@ -0,0 +1,149 @@
+#![warn(missing_docs)]
+
+use std::fmt::Debug;
+
+use kube_core::{params::PostParams, Resource};
+use serde::{de::DeserializeOwned, Serialize};
+
+use crate::{Api, Result};
+
+impl<K: Resource + Clone + DeserializeOwned + Debug> Api<K> {
+    pub async fn entry<'a>(&'a self, name: &'a str) -> Result<Entry<'a, K>> {
+        Ok(match self.try_get(name).await? {
+            Some(object) => Entry::Occupied(OccupiedEntry {
+                api: self,
+                object,
+                new: false,
+            }),
+            None => Entry::Vacant(VacantEntry { api: self, name }),
+        })
+    }
+}
+
+#[derive(Debug)]
+pub enum Entry<'a, K> {
+    Occupied(OccupiedEntry<'a, K>),
+    Vacant(VacantEntry<'a, K>),
+}
+
+impl<'a, K> Entry<'a, K> {
+    pub fn get(&self) -> Option<&K> {
+        match self {
+            Entry::Occupied(entry) => Some(entry.get()),
+            Entry::Vacant(_) => None,
+        }
+    }
+
+    pub fn get_mut(&mut self) -> Option<&mut K> {
+        match self {
+            Entry::Occupied(entry) => Some(entry.get_mut()),
+            Entry::Vacant(_) => None,
+        }
+    }
+
+    pub fn and_modify(self, f: impl FnOnce(&mut K)) -> Self {
+        match self {
+            Entry::Occupied(entry) => Entry::Occupied(entry.and_modify(f)),
+            entry @ Entry::Vacant(_) => entry,
+        }
+    }
+
+    pub fn or_insert(self, default: impl FnOnce() -> K) -> OccupiedEntry<'a, K>
+    where
+        K: Resource,
+    {
+        match self {
+            Entry::Occupied(entry) => entry,
+            Entry::Vacant(entry) => entry.insert(default()),
+        }
+    }
+}
+
+pub struct OccupiedEntry<'a, K> {
+    api: &'a Api<K>,
+    new: bool,
+    object: K,
+}
+
+impl<'a, K> OccupiedEntry<'a, K> {
+    pub fn get(&self) -> &K {
+        &self.object
+    }
+
+    pub fn get_mut(&mut self) -> &mut K {
+        &mut self.object
+    }
+
+    pub fn and_modify(mut self, f: impl FnOnce(&mut K)) -> Self {
+        f(&mut self.object);
+        self
+    }
+
+    pub fn into_object(self) -> K {
+        self.object
+    }
+
+    pub async fn sync(&mut self) -> Result<()>
+    where
+        K: Resource + DeserializeOwned + Serialize + Clone + Debug,
+    {
+        if self.new {
+            self.new = false;
+            self.object = self.api.create(&PostParams::default(), &self.object).await?;
+            Ok(())
+        } else {
+            self.object = self
+                .api
+                .replace(
+                    self.object.meta().name.as_deref().unwrap(),
+                    &PostParams::default(),
+                    &self.object,
+                )
+                .await?;
+            Ok(())
+        }
+    }
+}
+
+pub struct VacantEntry<'a, K> {
+    api: &'a Api<K>,
+    name: &'a str,
+}
+
+impl<'a, K> VacantEntry<'a, K> {
+    pub fn insert(self, mut object: K) -> OccupiedEntry<'a, K>
+    where
+        K: Resource,
+    {
+        let meta = object.meta_mut();
+        meta.name.get_or_insert_with(|| self.name.to_string());
+        if meta.namespace.is_none() {
+            meta.namespace = self.api.namespace.clone();
+        }
+        OccupiedEntry {
+            api: self.api,
+            object,
+            new: true,
+        }
+    }
+}
+
+impl<'a, K: Debug> Debug for OccupiedEntry<'a, K> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("OccupiedEntry")
+            .field("api", &"...")
+            .field("new", &self.new)
+            .field("object", &self.object)
+            .finish()
+    }
+}
+
+impl<'a, K> Debug for VacantEntry<'a, K> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("VacantEntry")
+            .field("api", &"...")
+            .field("name", &self.name)
+            .field("namespace", &self.api.namespace)
+            .finish()
+    }
+}

kube-client/src/api/mod.rs

@@ -15,6 +15,8 @@ pub use subresource::{Evict, EvictParams, Log, LogParams, ScaleSpec, ScaleStatus
 
 mod util;
 
+mod entry;
+
 // Re-exports from kube-core
 #[cfg(feature = "admission")]
 #[cfg_attr(docsrs, doc(cfg(feature = "admission")))]
@@ -46,6 +48,7 @@ pub struct Api<K> {
     pub(crate) request: Request,
     /// The client to use (from this library)
     pub(crate) client: Client,
+    namespace: Option<String>,
     /// Note: Using `iter::Empty` over `PhantomData`, because we never actually keep any
     /// `K` objects, so `Empty` better models our constraints (in particular, `Empty<K>`
     /// is `Send`, even if `K` may not be).
@@ -65,6 +68,7 @@ impl<K: Resource> Api<K> {
         Self {
             client,
             request: Request::new(url),
+            namespace: None,
             phantom: std::iter::empty(),
         }
     }
@@ -77,6 +81,7 @@ impl<K: Resource> Api<K> {
         Self {
             client,
             request: Request::new(url),
+            namespace: Some(ns.to_string()),
             phantom: std::iter::empty(),
         }
     }
@@ -88,12 +93,8 @@ impl<K: Resource> Api<K> {
     /// Unless configured explicitly, the default namespace is either "default"
     /// out of cluster, or the service account's namespace in cluster.
     pub fn default_namespaced_with(client: Client, dyntype: &K::DynamicType) -> Self {
-        let url = K::url_path(dyntype, Some(client.default_ns()));
-        Self {
-            client,
-            request: Request::new(url),
-            phantom: std::iter::empty(),
-        }
+        let ns = client.default_ns().to_string();
+        Self::namespaced_with(client, &ns, dyntype)
     }
 
     /// Consume self and return the [`Client`]
@@ -117,35 +118,20 @@ where
 {
     /// Cluster level resources, or resources viewed across all namespaces
     pub fn all(client: Client) -> Self {
-        let url = K::url_path(&Default::default(), None);
-        Self {
-            client,
-            request: Request::new(url),
-            phantom: std::iter::empty(),
-        }
+        Self::all_with(client, &K::DynamicType::default())
     }
 
     /// Namespaced resource within a given namespace
     pub fn namespaced(client: Client, ns: &str) -> Self {
-        let url = K::url_path(&Default::default(), Some(ns));
-        Self {
-            client,
-            request: Request::new(url),
-            phantom: std::iter::empty(),
-        }
+        Self::namespaced_with(client, ns, &K::DynamicType::default())
     }
 
     /// Namespaced resource within the default namespace
     ///
     /// Unless configured explicitly, the default namespace is either "default"
     /// out of cluster, or the service account's namespace in cluster.
     pub fn default_namespaced(client: Client) -> Self {
-        let url = K::url_path(&Default::default(), Some(client.default_ns()));
-        Self {
-            client,
-            request: Request::new(url),
-            phantom: std::iter::empty(),
-        }
+        Self::default_namespaced_with(client, &K::DynamicType::default())
     }
 }