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use callback::Callback; use config::{Config, MAX_WORKERS}; use park::{BoxPark, BoxedPark, DefaultPark}; use sender::Sender; use pool::{Pool, MAX_BACKUP}; use thread_pool::ThreadPool; use worker::{self, Worker, WorkerId}; use std::error::Error; use std::fmt; use std::sync::Arc; use std::time::Duration; use num_cpus; use tokio_executor::Enter; use tokio_executor::park::Park; #[cfg(feature = "unstable-futures")] use futures2; /// Builds a thread pool with custom configuration values. /// /// Methods can be chained in order to set the configuration values. The thread /// pool is constructed by calling [`build`]. /// /// New instances of `Builder` are obtained via [`Builder::new`]. /// /// See function level documentation for details on the various configuration /// settings. /// /// [`build`]: #method.build /// [`Builder::new`]: #method.new /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// use futures::future::{Future, lazy}; /// use std::time::Duration; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .pool_size(4) /// .keep_alive(Some(Duration::from_secs(30))) /// .build(); /// /// thread_pool.spawn(lazy(|| { /// println!("called from a worker thread"); /// Ok(()) /// })); /// /// // Gracefully shutdown the threadpool /// thread_pool.shutdown().wait().unwrap(); /// # } /// ``` pub struct Builder { /// Thread pool specific configuration values config: Config, /// Number of workers to spawn pool_size: usize, /// Maximum number of futures that can be in a blocking section /// concurrently. max_blocking: usize, /// Generates the `Park` instances new_park: Box<Fn(&WorkerId) -> BoxPark>, } impl Builder { /// Returns a new thread pool builder initialized with default configuration /// values. /// /// Configuration methods can be chained on the return value. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// use std::time::Duration; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .pool_size(4) /// .keep_alive(Some(Duration::from_secs(30))) /// .build(); /// # } /// ``` pub fn new() -> Builder { let num_cpus = num_cpus::get(); let new_park = Box::new(|_: &WorkerId| { Box::new(BoxedPark::new(DefaultPark::new())) as BoxPark }); Builder { pool_size: num_cpus, max_blocking: 100, config: Config { keep_alive: None, name_prefix: None, stack_size: None, around_worker: None, after_start: None, before_stop: None, }, new_park, } } /// Set the maximum number of worker threads for the thread pool instance. /// /// This must be a number between 1 and 32,768 though it is advised to keep /// this value on the smaller side. /// /// The default value is the number of cores available to the system. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .pool_size(4) /// .build(); /// # } /// ``` pub fn pool_size(&mut self, val: usize) -> &mut Self { assert!(val >= 1, "at least one thread required"); assert!(val <= MAX_WORKERS, "max value is {}", 32768); self.pool_size = val; self } /// Set the maximum number of concurrent blocking sections. /// /// When the maximum concurrent `blocking` calls is reached, any further /// calls to `blocking` will return `NotReady` and the task is notified once /// previously in-flight calls to `blocking` return. /// /// This must be a number between 1 and 32,768 though it is advised to keep /// this value on the smaller side. /// /// The default value is 100. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .max_blocking(200) /// .build(); /// # } /// ``` pub fn max_blocking(&mut self, val: usize) -> &mut Self { assert!(val <= MAX_BACKUP, "max value is {}", MAX_BACKUP); self.max_blocking = val; self } /// Set the worker thread keep alive duration /// /// If set, a worker thread will wait for up to the specified duration for /// work, at which point the thread will shutdown. When work becomes /// available, a new thread will eventually be spawned to replace the one /// that shut down. /// /// When the value is `None`, the thread will wait for work forever. /// /// The default value is `None`. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// use std::time::Duration; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .keep_alive(Some(Duration::from_secs(30))) /// .build(); /// # } /// ``` pub fn keep_alive(&mut self, val: Option<Duration>) -> &mut Self { self.config.keep_alive = val; self } /// Set name prefix of threads spawned by the scheduler /// /// Thread name prefix is used for generating thread names. For example, if /// prefix is `my-pool-`, then threads in the pool will get names like /// `my-pool-1` etc. /// /// If this configuration is not set, then the thread will use the system /// default naming scheme. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .name_prefix("my-pool-") /// .build(); /// # } /// ``` pub fn name_prefix<S: Into<String>>(&mut self, val: S) -> &mut Self { self.config.name_prefix = Some(val.into()); self } /// Set the stack size (in bytes) for worker threads. /// /// The actual stack size may be greater than this value if the platform /// specifies minimal stack size. /// /// The default stack size for spawned threads is 2 MiB, though this /// particular stack size is subject to change in the future. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .stack_size(32 * 1024) /// .build(); /// # } /// ``` pub fn stack_size(&mut self, val: usize) -> &mut Self { self.config.stack_size = Some(val); self } /// Execute function `f` on each worker thread. /// /// This function is provided a handle to the worker and is expected to call /// [`Worker::run`], otherwise the worker thread will shutdown without doing /// any work. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .around_worker(|worker, _| { /// println!("worker is starting up"); /// worker.run(); /// println!("worker is shutting down"); /// }) /// .build(); /// # } /// ``` /// /// [`Worker::run`]: struct.Worker.html#method.run pub fn around_worker<F>(&mut self, f: F) -> &mut Self where F: Fn(&Worker, &mut Enter) + Send + Sync + 'static { self.config.around_worker = Some(Callback::new(f)); self } /// Execute function `f` after each thread is started but before it starts /// doing work. /// /// This is intended for bookkeeping and monitoring use cases. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .after_start(|| { /// println!("thread started"); /// }) /// .build(); /// # } /// ``` pub fn after_start<F>(&mut self, f: F) -> &mut Self where F: Fn() + Send + Sync + 'static { self.config.after_start = Some(Arc::new(f)); self } /// Execute function `f` before each thread stops. /// /// This is intended for bookkeeping and monitoring use cases. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .before_stop(|| { /// println!("thread stopping"); /// }) /// .build(); /// # } /// ``` pub fn before_stop<F>(&mut self, f: F) -> &mut Self where F: Fn() + Send + Sync + 'static { self.config.before_stop = Some(Arc::new(f)); self } /// Customize the `park` instance used by each worker thread. /// /// The provided closure `f` is called once per worker and returns a `Park` /// instance that is used by the worker to put itself to sleep. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// # fn decorate<F>(f: F) -> F { f } /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .custom_park(|_| { /// use tokio_threadpool::park::DefaultPark; /// /// // This is the default park type that the worker would use if we /// // did not customize it. /// let park = DefaultPark::new(); /// /// // Decorate the `park` instance, allowing us to customize work /// // that happens when a worker thread goes to sleep. /// decorate(park) /// }) /// .build(); /// # } /// ``` pub fn custom_park<F, P>(&mut self, f: F) -> &mut Self where F: Fn(&WorkerId) -> P + 'static, P: Park + Send + 'static, P::Error: Error, { self.new_park = Box::new(move |id| { Box::new(BoxedPark::new(f(id))) }); self } /// Create the configured `ThreadPool`. /// /// The returned `ThreadPool` instance is ready to spawn tasks. /// /// # Examples /// /// ``` /// # extern crate tokio_threadpool; /// # extern crate futures; /// # use tokio_threadpool::Builder; /// /// # pub fn main() { /// let thread_pool = Builder::new() /// .build(); /// # } /// ``` pub fn build(&self) -> ThreadPool { let mut workers = vec![]; trace!("build; num-workers={}", self.pool_size); for i in 0..self.pool_size { let id = WorkerId::new(i); let park = (self.new_park)(&id); let unpark = park.unpark(); workers.push(worker::Entry::new(park, unpark)); } // Create the pool let inner = Arc::new( Pool::new( workers.into_boxed_slice(), self.max_blocking, self.config.clone())); // Wrap with `Sender` let inner = Some(Sender { inner }); ThreadPool { inner } } } impl fmt::Debug for Builder { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { fmt.debug_struct("Builder") .field("config", &self.config) .field("pool_size", &self.pool_size) .field("new_park", &"Box<Fn() -> BoxPark>") .finish() } }