1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
//! A batteries included runtime for applications using Tokio.
//!
//! Applications using Tokio require some runtime support in order to work:
//!
//! * A [reactor] to drive I/O resources.
//! * An [executor] to execute tasks that use these I/O resources.
//! * A [timer] for scheduling work to run after a set period of time.
//!
//! While it is possible to setup each component manually, this involves a bunch
//! of boilerplate.
//!
//! [`Runtime`] bundles all of these various runtime components into a single
//! handle that can be started and shutdown together, eliminating the necessary
//! boilerplate to run a Tokio application.
//!
//! Most applications wont need to use [`Runtime`] directly. Instead, they will
//! use the [`run`] function, which uses [`Runtime`] under the hood.
//!
//! Creating a [`Runtime`] does the following:
//!
//! * Spawn a background thread running a [`Reactor`] instance.
//! * Start a [`ThreadPool`] for executing futures.
//! * Run an instance of [`Timer`] **per** thread pool worker thread.
//!
//! The thread pool uses a work-stealing strategy and is configured to start a
//! worker thread for each CPU core available on the system. This tends to be
//! the ideal setup for Tokio applications.
//!
//! A timer per thread pool worker thread is used to minimize the amount of
//! synchronization that is required for working with the timer.
//!
//! # Usage
//!
//! Most applications will use the [`run`] function. This takes a future to
//! "seed" the application, blocking the thread until the runtime becomes
//! [idle].
//!
//! ```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() {}
//! ```
//!
//! In this function, the `run` function blocks until the runtime becomes idle.
//! See [`shutdown_on_idle`][idle] for more shutdown details.
//!
//! From within the context of the runtime, additional tasks are spawned using
//! the [`tokio::spawn`] function. Futures spawned using this function will be
//! executed on the same thread pool used by the [`Runtime`].
//!
//! A [`Runtime`] instance can also be used directly.
//!
//! ```rust
//! # extern crate tokio;
//! # extern crate futures;
//! # use futures::{Future, Stream};
//! use tokio::runtime::Runtime;
//! 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))
//!     });
//!
//! // Create the runtime
//! let mut rt = Runtime::new().unwrap();
//!
//! // Spawn the server task
//! rt.spawn(server);
//!
//! // Wait until the runtime becomes idle and shut it down.
//! rt.shutdown_on_idle()
//!     .wait().unwrap();
//! # }
//! # pub fn main() {}
//! ```
//!
//! [reactor]: ../reactor/struct.Reactor.html
//! [executor]: https://tokio.rs/docs/getting-started/runtime-model/#executors
//! [timer]: ../timer/index.html
//! [`Runtime`]: struct.Runtime.html
//! [`Reactor`]: ../reactor/struct.Reactor.html
//! [`ThreadPool`]: ../executor/thread_pool/struct.ThreadPool.html
//! [`run`]: fn.run.html
//! [idle]: struct.Runtime.html#method.shutdown_on_idle
//! [`tokio::spawn`]: ../executor/fn.spawn.html
//! [`Timer`]: https://docs.rs/tokio-timer/0.2/tokio_timer/timer/struct.Timer.html

mod builder;
pub mod current_thread;
mod shutdown;
mod task_executor;

pub use self::builder::Builder;
pub use self::shutdown::Shutdown;
pub use self::task_executor::TaskExecutor;

use reactor::{Background, Handle};

use std::io;

use tokio_threadpool as threadpool;

use futures;
use futures::future::Future;
#[cfg(feature = "unstable-futures")]
use futures2;

/// 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 {
    /// Reactor running on a background thread.
    reactor: Background,

    /// 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,
{
    let mut runtime = Runtime::new().unwrap();
    runtime.spawn(future);
    runtime.shutdown_on_idle().wait().unwrap();
}

/// Start the Tokio runtime using the supplied future to bootstrap execution.
///
/// Identical to `run` but works with futures 0.2-style futures.
#[cfg(feature = "unstable-futures")]
pub fn run2<F>(future: F)
    where F: futures2::Future<Item = (), Error = futures2::Never> + Send + 'static,
{
    let mut runtime = Runtime::new().unwrap();
    runtime.spawn2(future);
    runtime.shutdown_on_idle().wait().unwrap();
}

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 {
        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`
    /// ```
    pub fn reactor(&self) -> &Handle {
        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
    }

    /// Spawn a futures 0.2-style future onto the Tokio runtime.
    ///
    /// Otherwise identical to `spawn`
    #[cfg(feature = "unstable-futures")]
    pub fn spawn2<F>(&mut self, future: F) -> &mut Self
        where F: futures2::Future<Item = (), Error = futures2::Never> + Send + 'static,
    {
        futures2::executor::Executor::spawn(
            self.inner_mut().pool.sender_mut(), Box::new(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 asynchrounous 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 (tx, rx) = futures::sync::oneshot::channel();
        self.spawn(future.then(move |r| tx.send(r).map_err(|_| unreachable!())));
        rx.wait().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 = Box::new({
            let pool = inner.pool;
            let reactor = inner.reactor;

            pool.shutdown_on_idle().and_then(|_| {
                reactor.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();
        }
    }
}