Menü
Common Tokio patterns and idioms for async programming. Use when implementing worker pools, request-response patterns, pub/sub, timeouts, retries, or graceful shutdown.
Mit Codex oder Claude installieren Kopieren Sie diesen Prompt, fügen Sie ihn in Codex, Claude oder einen anderen Assistant ein und lassen Sie die Skill-Seite prüfen und installieren.
Basierend auf der SOC-Berufsklassifikation
Common Clap patterns and idioms for argument parsing, validation, and CLI design. Use when implementing CLI arguments with Clap v4+.
Configuration management patterns including file formats, precedence, environment variables, and XDG directories. Use when implementing configuration systems for CLI applications.
Distribution and packaging patterns including shell completions, man pages, cross-compilation, and release automation. Use when preparing CLI tools for distribution.
CLI user experience best practices for error messages, colors, progress indicators, and output formatting. Use when improving CLI usability and user experience.
Advanced concurrency patterns for Tokio including fan-out/fan-in, pipeline processing, rate limiting, and coordinated shutdown. Use when building high-concurrency async systems.
Network programming patterns with Hyper, Tonic, and Tower. Use when building HTTP services, gRPC applications, implementing middleware, connection pooling, or health checks.
| name | tokio-patterns |
| description | Common Tokio patterns and idioms for async programming. Use when implementing worker pools, request-response patterns, pub/sub, timeouts, retries, or graceful shutdown. |
This skill provides common patterns and idioms for building robust async applications with Tokio.
Limit concurrent task execution using a semaphore:
use tokio::sync::Semaphore;
use std::sync::Arc;
pub struct WorkerPool {
semaphore: Arc<Semaphore>,
}
impl WorkerPool {
pub fn new(size: usize) -> Self {
Self {
semaphore: Arc::new(Semaphore::new(size)),
}
}
pub async fn execute<F, T>(&self, f: F) -> T
where
F: Future<Output = T>,
{
let _permit = self.semaphore.acquire().await.unwrap();
f.await
}
}
// Usage
let pool = WorkerPool::new(10);
let results = futures::future::join_all(
(0..100).map(|i| pool.execute(process_item(i)))
).await;
Use oneshot channels for request-response communication:
use tokio::sync::{mpsc, oneshot};
pub enum Command {
Get { key: String, respond_to: oneshot::Sender<Option<String>> },
Set { key: String, value: String },
}
pub async fn actor(mut rx: mpsc::Receiver<Command>) {
let mut store = HashMap::new();
while let Some(cmd) = rx.recv().await {
match cmd {
Command::Get { key, respond_to } => {
let value = store.get(&key).cloned();
let _ = respond_to.send(value);
}
Command::Set { key, value } => {
store.insert(key, value);
}
}
}
}
// Client usage
let (tx, rx) = mpsc::channel(32);
tokio::spawn(actor(rx));
let (respond_to, response) = oneshot::channel();
tx.send(Command::Get { key: "foo".into(), respond_to }).await.unwrap();
let value = response.await.unwrap();
Use broadcast channels for pub/sub messaging:
use tokio::sync::broadcast;
pub struct PubSub<T: Clone> {
tx: broadcast::Sender<T>,
}
impl<T: Clone> PubSub<T> {
pub fn new(capacity: usize) -> Self {
let (tx, _) = broadcast::channel(capacity);
Self { tx }
}
pub fn subscribe(&self) -> broadcast::Receiver<T> {
self.tx.subscribe()
}
pub fn publish(&self, message: T) -> Result<usize, broadcast::error::SendError<T>> {
self.tx.send(message)
}
}
// Usage
let pubsub = PubSub::new(100);
// Subscriber 1
let mut rx1 = pubsub.subscribe();
tokio::spawn(async move {
while let Ok(msg) = rx1.recv().await {
println!("Subscriber 1: {:?}", msg);
}
});
// Subscriber 2
let mut rx2 = pubsub.subscribe();
tokio::spawn(async move {
while let Ok(msg) = rx2.recv().await {
println!("Subscriber 2: {:?}", msg);
}
});
// Publisher
pubsub.publish("Hello".to_string()).unwrap();
Wrap operations with timeouts:
use tokio::time::{timeout, Duration};
pub async fn with_timeout<F, T>(duration: Duration, future: F) -> Result<T, TimeoutError>
where
F: Future<Output = Result<T, Error>>,
{
match timeout(duration, future).await {
Ok(Ok(result)) => Ok(result),
Ok(Err(e)) => Err(TimeoutError::Inner(e)),
Err(_) => Err(TimeoutError::Elapsed),
}
}
// Usage
let result = with_timeout(
Duration::from_secs(5),
fetch_data()
).await?;
Retry failed operations with backoff:
use tokio::time::{sleep, Duration};
pub async fn retry_with_backoff<F, T, E>(
mut operation: F,
max_retries: u32,
initial_backoff: Duration,
) -> Result<T, E>
where
F: FnMut() -> Pin<Box<dyn Future<Output = Result<T, E>>>>,
{
let mut retries = 0;
let mut backoff = initial_backoff;
loop {
match operation().await {
Ok(result) => return Ok(result),
Err(e) if retries < max_retries => {
retries += 1;
sleep(backoff).await;
backoff *= 2; // Exponential backoff
}
Err(e) => return Err(e),
}
}
}
// Usage
let result = retry_with_backoff(
|| Box::pin(fetch_data()),
3,
Duration::from_millis(100)
).await?;
Coordinate graceful shutdown across components:
use tokio::sync::broadcast;
use tokio::select;
pub struct ShutdownCoordinator {
tx: broadcast::Sender<()>,
}
impl ShutdownCoordinator {
pub fn new() -> Self {
let (tx, _) = broadcast::channel(1);
Self { tx }
}
pub fn subscribe(&self) -> broadcast::Receiver<()> {
self.tx.subscribe()
}
pub fn shutdown(&self) {
let _ = self.tx.send(());
}
}
// Worker pattern
pub async fn worker(mut shutdown: broadcast::Receiver<()>) {
loop {
select! {
_ = shutdown.recv() => {
// Cleanup
break;
}
result = do_work() => {
// Process result
}
}
}
}
// Main
let coordinator = ShutdownCoordinator::new();
let shutdown_rx1 = coordinator.subscribe();
let h1 = tokio::spawn(worker(shutdown_rx1));
let shutdown_rx2 = coordinator.subscribe();
let h2 = tokio::spawn(worker(shutdown_rx2));
// Wait for signal
tokio::signal::ctrl_c().await.unwrap();
coordinator.shutdown();
// Wait for workers
let _ = tokio::join!(h1, h2);
Lazy async initialization with OnceCell:
use tokio::sync::OnceCell;
pub struct Service {
connection: OnceCell<Connection>,
}
impl Service {
pub fn new() -> Self {
Self {
connection: OnceCell::new(),
}
}
async fn get_connection(&self) -> &Connection {
self.connection
.get_or_init(|| async {
Connection::connect().await.unwrap()
})
.await
}
pub async fn query(&self, sql: &str) -> Result<Vec<Row>> {
let conn = self.get_connection().await;
conn.query(sql).await
}
}
Ensure cleanup even on task cancellation:
pub struct Resource {
handle: SomeHandle,
}
impl Resource {
pub async fn new() -> Self {
Self {
handle: acquire_resource().await,
}
}
pub async fn use_resource(&self) -> Result<()> {
// Use the resource
Ok(())
}
}
impl Drop for Resource {
fn drop(&mut self) {
// Synchronous cleanup
// For async cleanup, use a separate shutdown method
self.handle.close();
}
}
// For async cleanup
impl Resource {
pub async fn shutdown(self) {
// Async cleanup
self.handle.close_async().await;
}
}
Use select! to race multiple operations:
use tokio::select;
pub async fn select_example() {
let mut rx1 = channel1();
let mut rx2 = channel2();
loop {
select! {
msg = rx1.recv() => {
if let Some(msg) = msg {
handle_channel1(msg).await;
} else {
break;
}
}
msg = rx2.recv() => {
if let Some(msg) = msg {
handle_channel2(msg).await;
} else {
break;
}
}
_ = tokio::time::sleep(Duration::from_secs(60)) => {
check_timeout().await;
}
}
}
}
Use tokio_util::sync::CancellationToken for cooperative cancellation:
use tokio_util::sync::CancellationToken;
pub async fn worker(token: CancellationToken) {
loop {
tokio::select! {
_ = token.cancelled() => {
// Cleanup
break;
}
_ = do_work() => {
// Continue
}
}
}
}
// Hierarchical cancellation
let parent_token = CancellationToken::new();
let child_token = parent_token.child_token();
tokio::spawn(worker(child_token));
// Cancel all
parent_token.cancel();