Add renovate.json

chore(release): 0.1.2

Co-authored-by: cuddle-please <bot@cuddle.sh>
Reviewed-on: https://git.front.kjuulh.io/kjuulh/noleader/pulls/2

CHANGELOG.md

@@ -6,6 +6,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.1.2] - 2025-07-04
+
+### Added
+- update basic example with a more simple acquire and run function
+
+### Docs
+- update master
+
 ## [0.1.1] - 2025-07-04
 
 ### Added

Cargo.lock

@@ -645,7 +645,7 @@ dependencies = [
 
 [[package]]
 name = "noleader"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "anyhow",
  "async-nats",

Cargo.toml

@@ -3,7 +3,7 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.package]
-version = "0.1.1"
+version = "0.1.2"
 license = "MIT"
 
 [workspace.dependencies]

README.md

@@ -71,31 +71,28 @@ async fn main() -> anyhow::Result<()> {
     // Ensure the KV bucket exists
     leader.create_bucket().await?;
 
-    // Spawn the election loop
+    // Attempts to acquire election loop, will call inner function if it wins, if it loses it will retry over again.
-    tokio::spawn({
+    // Will block until either the inner function returns and error, or the election processes crashes, intended to allow the application to properly restart
-        let leader = leader.clone();
-        async move {
-            leader
-                .start(CancellationToken::default())
-                .await
-                .expect("leadership loop failed");
-        }
-    });
-
-    // Do work while we are the leader
     leader
-        .do_while_leader(|cancel_token| async move {
+        .acquire_and_run({
-            loop {
+            move |token| {
-                if cancel_token.is_cancelled() {
+                let leader_id = leader_id.clone();
-                    break;
+
+                async move {
+                    loop {
+                        if token.is_cancelled() {
+                            return Ok(());
+                        }
+
+                        tracing::info!(leader_id, "do work as leader");
+                        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                    }
                 }
-                tracing::info!("🔑 I am the leader—doing work");
-                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
             }
-            Ok(())
         })
         .await?;
 
+
     Ok(())
 }
 ```

crates/noleader/Cargo.toml

@@ -1,7 +1,12 @@
 [package]
 name = "noleader"
-version = "0.1.0"
+edition = "2024"
-edition = "2021"
+readme = "../../README.md"
+version.workspace = true
+license.workspace = true
+repository = "https://git.front.kjuulh.io/kjuulh/noleader"
+authors = ["kjuulh <contact@kasperhermansen.com>"]
+description = "A small leader election package using NATS keyvalue store as the distributed locking mechanism. Does not require a min / max set of nodes"
 
 [dependencies]
 anyhow.workspace = true

crates/noleader/examples/basic/main.rs

@@ -23,28 +23,21 @@ async fn main() -> anyhow::Result<()> {
     tracing::info!("creating bucket");
     leader.create_bucket().await?;
 
-    tokio::spawn({
-        let leader = leader.clone();
-        let leader_id = leader_id.clone();
-
-        async move {
-            tracing::debug!(leader_id, "starting leader");
-            leader
-                .start(CancellationToken::default())
-                .await
-                .expect("to succeed");
-        }
-    });
-
     leader
-        .do_while_leader(move |token| async move {
+        .acquire_and_run({
-            loop {
+            move |token| {
-                if token.is_cancelled() {
+                let leader_id = leader_id.clone();
-                    return Ok(());
-                }
 
-                tracing::info!("do work as leader");
+                async move {
-                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                    loop {
+                        if token.is_cancelled() {
+                            return Ok(());
+                        }
+
+                        tracing::info!(leader_id, "do work as leader");
+                        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                    }
+                }
             }
         })
         .await?;

crates/noleader/src/lib.rs

@@ -31,19 +31,72 @@ impl Leader {
         }
     }
 
+    pub async fn acquire_and_run<F, Fut>(&self, f: F) -> anyhow::Result<()>
+    where
+        F: Fn(CancellationToken) -> Fut,
+        Fut: Future<Output = anyhow::Result<()>> + Send + 'static,
+    {
+        let parent_token = CancellationToken::default();
+        let s = self.clone();
+
+        let server_token = parent_token.child_token();
+
+        // Start the server election process in another task, this is because start is blocking
+        let handle = tokio::spawn({
+            let server_token = server_token.child_token();
+            async move {
+                match s.start(server_token).await {
+                    Ok(_) => {}
+                    Err(e) => tracing::error!("leader election process failed: {}", e),
+                }
+
+                tracing::info!("shutting down noleader");
+
+                parent_token.cancel();
+            }
+        });
+
+        // Do the work if we're leader
+        let res = self
+            .do_while_leader_inner(server_token.child_token(), f)
+            .await;
+
+        // Stop the server election process if our provided functions returns an error;
+        server_token.cancel();
+        // Close down the task as well, it should already be stopped, but this forces the task to close
+        handle.abort();
+        res?;
+
+        Ok(())
+    }
+
     pub async fn do_while_leader<F, Fut>(&self, f: F) -> anyhow::Result<()>
+    where
+        F: Fn(CancellationToken) -> Fut,
+        Fut: Future<Output = anyhow::Result<()>> + Send + 'static,
+    {
+        self.do_while_leader_inner(CancellationToken::new(), f)
+            .await
+    }
+
+    async fn do_while_leader_inner<F, Fut>(
+        &self,
+        cancellation_token: CancellationToken,
+        f: F,
+    ) -> anyhow::Result<()>
     where
         F: Fn(CancellationToken) -> Fut,
         Fut: Future<Output = anyhow::Result<()>> + Send + 'static,
     {
         loop {
+            let cancellation_token = cancellation_token.child_token();
+
             let is_leader = self.is_leader.clone();
             if !is_leader.load(Ordering::Relaxed) {
                 tokio::time::sleep(Duration::from_secs(1)).await;
                 continue;
             }
 
-            let cancellation_token = CancellationToken::new();
             let child_token = cancellation_token.child_token();
 
             let guard = tokio::spawn(async move {

renovate.json

@@ -0,0 +1,3 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json"
+}