Add lease-based leader election

.github/workflows/pr.yml

@@ -4,7 +4,7 @@ on:
 
 env:
   DOCKER_BUILDKIT: "1"
-  K8S_OPENAPI_ENABLED_VERSION: "1.32"
+  K8S_OPENAPI_ENABLED_VERSION: "1.34"
 
 jobs:
   lint:

CHANGELOG.md

@@ -1,5 +1,22 @@
 # Changelog
 
+## [0.12.0] - 2026-07-22
+
+### Added
+
+* `LeaderElection`, providing lease-based leader election so that multiple
+  replicas of a controller can run with only one reconciling at a time.
+  `LeaderElection::with_lease` runs an arbitrary future (for instance, one
+  or several `Controller::run` futures) while holding the lease.
+  `LeaderElection::release` allows handing leadership over immediately
+  during graceful shutdown.
+
+### Changed
+
+* `k8s-openapi` is now a regular dependency, with no version feature
+  enabled; the final binary crate is responsible for enabling one.
+* Update the k8s-openapi version feature used in CI and tests to `v1_34`.
+
 ## [0.3.2] - 2024-07-23
 
 ### Changed

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "k8s-controller"
-version = "0.11.0"
+version = "0.12.0"
 edition = "2024"
 rust-version = "1.89.0"
 
@@ -13,16 +13,20 @@ include = ["src/**/*", "LICENSE", "README.md", "CHANGELOG.md"]
 [dependencies]
 async-trait = "0.1"
 futures = "0.3"
+# no version feature is enabled here; the final binary crate is responsible
+# for enabling one, as described in the k8s-openapi docs
+k8s-openapi = { version = "0.27.0", default-features = false }
 kube = { version = "3.0.0", default-features = false, features = ["client"] }
 kube-runtime = "3.0.0"
 rand = "0.9.2"
 serde = "1"
 serde_json = "1"
 thiserror = "2.0.17"
+tokio = { version = "1", features = ["time"] }
 tracing = "0.1"
 
 [dev-dependencies]
-k8s-openapi = { version = "0.27.0", default-features = false, features = ["v1_32"] }
+k8s-openapi = { version = "0.27.0", default-features = false, features = ["v1_34"] }
 tokio = "1"
 
 [package.metadata.docs.rs]

src/controller.rs

@@ -149,6 +149,10 @@ where
     /// method called when a resource is created or updated, and its
     /// [`cleanup`](Context::cleanup) method called when a resource is about
     /// to be deleted.
+    ///
+    /// To run multiple replicas of a controller with only one reconciling
+    /// at a time, pass this method's future to
+    /// [`LeaderElection::with_lease`](crate::LeaderElection::with_lease).
     pub async fn run(self) {
         let Self {
             client,