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mod builder; mod shutdown; mod task_executor; #[cfg(feature = "async-await-preview")] mod async_await; pub use self::builder::Builder; pub use self::shutdown::Shutdown; pub use self::task_executor::TaskExecutor; use reactor::{Handle, Reactor}; use std::io; use std::sync::Mutex; use tokio_executor::enter; use tokio_threadpool as threadpool; use futures; use futures::future::Future; /// Handle to the Tokio runtime. /// /// The Tokio runtime includes a reactor as well as an executor for running /// tasks. /// /// Instances of `Runtime` can be created using [`new`] or [`Builder`]. However, /// most users will use [`tokio::run`], which uses a `Runtime` internally. /// /// See [module level][mod] documentation for more details. /// /// [mod]: index.html /// [`new`]: #method.new /// [`Builder`]: struct.Builder.html /// [`tokio::run`]: fn.run.html #[derive(Debug)] pub struct Runtime { inner: Option<Inner>, } #[derive(Debug)] struct Inner { /// A handle to the reactor in the background thread. reactor_handle: Handle, // TODO: This should go away in 0.2 reactor: Mutex<Option<Reactor>>, /// Task execution pool. pool: threadpool::ThreadPool, } // ===== impl Runtime ===== /// Start the Tokio runtime using the supplied future to bootstrap execution. /// /// This function is used to bootstrap the execution of a Tokio application. It /// does the following: /// /// * Start the Tokio runtime using a default configuration. /// * Spawn the given future onto the thread pool. /// * Block the current thread until the runtime shuts down. /// /// Note that the function will not return immediately once `future` has /// completed. Instead it waits for the entire runtime to become idle. /// /// See the [module level][mod] documentation for more details. /// /// # Examples /// /// ```rust /// # extern crate tokio; /// # extern crate futures; /// # use futures::{Future, Stream}; /// use tokio::net::TcpListener; /// /// # fn process<T>(_: T) -> Box<Future<Item = (), Error = ()> + Send> { /// # unimplemented!(); /// # } /// # fn dox() { /// # let addr = "127.0.0.1:8080".parse().unwrap(); /// let listener = TcpListener::bind(&addr).unwrap(); /// /// let server = listener.incoming() /// .map_err(|e| println!("error = {:?}", e)) /// .for_each(|socket| { /// tokio::spawn(process(socket)) /// }); /// /// tokio::run(server); /// # } /// # pub fn main() {} /// ``` /// /// # Panics /// /// This function panics if called from the context of an executor. /// /// [mod]: ../index.html pub fn run<F>(future: F) where F: Future<Item = (), Error = ()> + Send + 'static, { // Check enter before creating a new Runtime... let mut entered = enter().expect("nested tokio::run"); let mut runtime = Runtime::new().expect("failed to start new Runtime"); runtime.spawn(future); entered .block_on(runtime.shutdown_on_idle()) .expect("shutdown cannot error") } impl Runtime { /// Create a new runtime instance with default configuration values. /// /// This results in a reactor, thread pool, and timer being initialized. The /// thread pool will not spawn any worker threads until it needs to, i.e. /// tasks are scheduled to run. /// /// Most users will not need to call this function directly, instead they /// will use [`tokio::run`](fn.run.html). /// /// See [module level][mod] documentation for more details. /// /// # Examples /// /// Creating a new `Runtime` with default configuration values. /// /// ``` /// use tokio::runtime::Runtime; /// use tokio::prelude::*; /// /// let rt = Runtime::new() /// .unwrap(); /// /// // Use the runtime... /// /// // Shutdown the runtime /// rt.shutdown_now() /// .wait().unwrap(); /// ``` /// /// [mod]: index.html pub fn new() -> io::Result<Self> { Builder::new().build() } #[deprecated(since = "0.1.5", note = "use `reactor` instead")] #[doc(hidden)] pub fn handle(&self) -> &Handle { #[allow(deprecated)] self.reactor() } /// Return a reference to the reactor handle for this runtime instance. /// /// The returned handle reference can be cloned in order to get an owned /// value of the handle. This handle can be used to initialize I/O resources /// (like TCP or UDP sockets) that will not be used on the runtime. /// /// # Examples /// /// ``` /// use tokio::runtime::Runtime; /// /// let rt = Runtime::new() /// .unwrap(); /// /// let reactor_handle = rt.reactor().clone(); /// /// // use `reactor_handle` /// ``` #[deprecated(since = "0.1.11", note = "there is now a reactor per worker thread")] pub fn reactor(&self) -> &Handle { let mut reactor = self.inner().reactor.lock().unwrap(); if let Some(reactor) = reactor.take() { if let Ok(background) = reactor.background() { background.forget(); } } &self.inner().reactor_handle } /// Return a handle to the runtime's executor. /// /// The returned handle can be used to spawn tasks that run on this runtime. /// /// # Examples /// /// ``` /// use tokio::runtime::Runtime; /// /// let rt = Runtime::new() /// .unwrap(); /// /// let executor_handle = rt.executor(); /// /// // use `executor_handle` /// ``` pub fn executor(&self) -> TaskExecutor { let inner = self.inner().pool.sender().clone(); TaskExecutor { inner } } /// Spawn a future onto the Tokio runtime. /// /// This spawns the given future onto the runtime's executor, usually a /// thread pool. The thread pool is then responsible for polling the future /// until it completes. /// /// See [module level][mod] documentation for more details. /// /// [mod]: index.html /// /// # Examples /// /// ```rust /// # extern crate tokio; /// # extern crate futures; /// # use futures::{future, Future, Stream}; /// use tokio::runtime::Runtime; /// /// # fn dox() { /// // Create the runtime /// let mut rt = Runtime::new().unwrap(); /// /// // Spawn a future onto the runtime /// rt.spawn(future::lazy(|| { /// println!("now running on a worker thread"); /// Ok(()) /// })); /// # } /// # pub fn main() {} /// ``` /// /// # Panics /// /// This function panics if the spawn fails. Failure occurs if the executor /// is currently at capacity and is unable to spawn a new future. pub fn spawn<F>(&mut self, future: F) -> &mut Self where F: Future<Item = (), Error = ()> + Send + 'static, { self.inner_mut().pool.sender().spawn(future).unwrap(); self } /// Run a future to completion on the Tokio runtime. /// /// This runs the given future on the runtime, blocking until it is /// complete, and yielding its resolved result. Any tasks or timers which /// the future spawns internally will be executed on the runtime. /// /// This method should not be called from an asynchronous context. /// /// # Panics /// /// This function panics if the executor is at capacity, if the provided /// future panics, or if called within an asynchronous execution context. pub fn block_on<F, R, E>(&mut self, future: F) -> Result<R, E> where F: Send + 'static + Future<Item = R, Error = E>, R: Send + 'static, E: Send + 'static, { let mut entered = enter().expect("nested block_on"); let (tx, rx) = futures::sync::oneshot::channel(); self.spawn(future.then(move |r| tx.send(r).map_err(|_| unreachable!()))); entered.block_on(rx).unwrap() } /// Run a future to completion on the Tokio runtime, then wait for all /// background futures to complete too. /// /// This runs the given future on the runtime, blocking until it is /// complete, waiting for background futures to complete, and yielding /// its resolved result. Any tasks or timers which the future spawns /// internally will be executed on the runtime and waited for completion. /// /// This method should not be called from an asynchronous context. /// /// # Panics /// /// This function panics if the executor is at capacity, if the provided /// future panics, or if called within an asynchronous execution context. pub fn block_on_all<F, R, E>(mut self, future: F) -> Result<R, E> where F: Send + 'static + Future<Item = R, Error = E>, R: Send + 'static, E: Send + 'static, { let mut entered = enter().expect("nested block_on_all"); let (tx, rx) = futures::sync::oneshot::channel(); self.spawn(future.then(move |r| tx.send(r).map_err(|_| unreachable!()))); let block = rx .map_err(|_| unreachable!()) .and_then(move |r| { self.shutdown_on_idle() .map(move |()| r) }); entered.block_on(block).unwrap() } /// Signals the runtime to shutdown once it becomes idle. /// /// Returns a future that completes once the shutdown operation has /// completed. /// /// This function can be used to perform a graceful shutdown of the runtime. /// /// The runtime enters an idle state once **all** of the following occur. /// /// * The thread pool has no tasks to execute, i.e., all tasks that were /// spawned have completed. /// * The reactor is not managing any I/O resources. /// /// See [module level][mod] documentation for more details. /// /// # Examples /// /// ``` /// use tokio::runtime::Runtime; /// use tokio::prelude::*; /// /// let rt = Runtime::new() /// .unwrap(); /// /// // Use the runtime... /// /// // Shutdown the runtime /// rt.shutdown_on_idle() /// .wait().unwrap(); /// ``` /// /// [mod]: index.html pub fn shutdown_on_idle(mut self) -> Shutdown { let inner = self.inner.take().unwrap(); let inner = inner.pool.shutdown_on_idle(); Shutdown { inner } } /// Signals the runtime to shutdown immediately. /// /// Returns a future that completes once the shutdown operation has /// completed. /// /// This function will forcibly shutdown the runtime, causing any /// in-progress work to become canceled. The shutdown steps are: /// /// * Drain any scheduled work queues. /// * Drop any futures that have not yet completed. /// * Drop the reactor. /// /// Once the reactor has dropped, any outstanding I/O resources bound to /// that reactor will no longer function. Calling any method on them will /// result in an error. /// /// See [module level][mod] documentation for more details. /// /// # Examples /// /// ``` /// use tokio::runtime::Runtime; /// use tokio::prelude::*; /// /// let rt = Runtime::new() /// .unwrap(); /// /// // Use the runtime... /// /// // Shutdown the runtime /// rt.shutdown_now() /// .wait().unwrap(); /// ``` /// /// [mod]: index.html pub fn shutdown_now(mut self) -> Shutdown { let inner = self.inner.take().unwrap(); Shutdown::shutdown_now(inner) } fn inner(&self) -> &Inner { self.inner.as_ref().unwrap() } fn inner_mut(&mut self) -> &mut Inner { self.inner.as_mut().unwrap() } } impl Drop for Runtime { fn drop(&mut self) { if let Some(inner) = self.inner.take() { let shutdown = Shutdown::shutdown_now(inner); let _ = shutdown.wait(); } } }