thread pool
This commit is contained in:
parent
ed06a50aa8
commit
a0808728ad
@ -1,31 +1,53 @@
|
||||
use std::{
|
||||
io::{prelude::*, BufReader},
|
||||
io::{prelude::*, BufReader, Lines},
|
||||
net::{TcpListener, TcpStream},
|
||||
};
|
||||
use std::io::Lines;
|
||||
use std::thread::available_parallelism;
|
||||
use crate::thread_pool::ThreadPool;
|
||||
|
||||
mod thread_pool;
|
||||
|
||||
|
||||
fn main() {
|
||||
// start server on localhost (for remote access use: 0.0.0.0)
|
||||
let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
|
||||
|
||||
// create thread pool (size = no. of cpu cores)
|
||||
let pool = ThreadPool::new(available_parallelism().unwrap().get());
|
||||
|
||||
// handling function for incoming requests
|
||||
for stream in listener.incoming() {
|
||||
let stream = stream.unwrap();
|
||||
|
||||
handle_connection(stream);
|
||||
// pass request to thread pool
|
||||
pool.execute(|| {
|
||||
handle_connection(stream);
|
||||
});
|
||||
}
|
||||
println!("Shutting down.");
|
||||
}
|
||||
|
||||
|
||||
fn handle_connection(mut stream: TcpStream) {
|
||||
// clone TcpStream for simultaneous receiving and sending
|
||||
let mut stream2: TcpStream = stream.try_clone().unwrap();
|
||||
|
||||
// initialize reading buffer (for better performance!)
|
||||
let buf_reader: BufReader<&mut TcpStream> = BufReader::new(&mut stream);
|
||||
// request: read received text line by line (continuous until connection closed)
|
||||
let request: Lines<BufReader<&mut TcpStream>> = buf_reader.lines();
|
||||
|
||||
println!("Request: {:#?}", request);
|
||||
|
||||
// processing function for every text line received by request (terminates when conn closed)
|
||||
for elem in request
|
||||
{
|
||||
// store received line in variable s
|
||||
let s = elem.unwrap();
|
||||
println!("{:?}", s);
|
||||
stream2.write(s.as_bytes()).unwrap();
|
||||
|
||||
// send received line back to sender (append LF)
|
||||
stream2.write_all(s.as_bytes()).unwrap();
|
||||
stream2.write_all(b"\n").unwrap();
|
||||
}
|
||||
}
|
||||
|
116
src/bin/thread_pool.rs
Normal file
116
src/bin/thread_pool.rs
Normal file
@ -0,0 +1,116 @@
|
||||
use std::{
|
||||
sync::{mpsc, Arc, Mutex},
|
||||
thread
|
||||
};
|
||||
|
||||
|
||||
pub struct ThreadPool {
|
||||
workers: Vec<Worker>,
|
||||
sender: Option<mpsc::Sender<Job>>,
|
||||
}
|
||||
|
||||
// Box: pointer for heap allocation (smart pointer); dyn: unknown type to compile time
|
||||
type Job = Box<dyn FnOnce() + Send + 'static>;
|
||||
|
||||
|
||||
impl ThreadPool {
|
||||
/// Create a new ThreadPool.
|
||||
///
|
||||
/// The size is the number of threads in the pool.
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// The `new` function will panic if the size is zero.
|
||||
pub fn new(size: usize) -> ThreadPool {
|
||||
assert!(size > 0);
|
||||
|
||||
// create asynchronous channel with sender/receiver pair (for jobs!)
|
||||
let (sender, receiver) = mpsc::channel();
|
||||
|
||||
// protect receiver with thread-safe shared (Arc) mutex to avoid multiple access
|
||||
let receiver = Arc::new(Mutex::new(receiver));
|
||||
|
||||
// pre(!)allocate space for workers
|
||||
let mut workers = Vec::with_capacity(size);
|
||||
|
||||
// initialize all workers...
|
||||
for id in 0..size {
|
||||
// create worker with unique id and pointer to the shared mutex
|
||||
workers.push(Worker::new(id, Arc::clone(&receiver)));
|
||||
}
|
||||
|
||||
// set thread pool variables
|
||||
ThreadPool {
|
||||
workers,
|
||||
// Some --> enum variant (Option): indicates that sender may not exist (=be null)
|
||||
sender: Some(sender),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn execute<F>(&self, f: F)
|
||||
where
|
||||
// FnOnce() --> only callable once; Send --> transfer to another thread; 'static --> lifetime
|
||||
F: FnOnce() + Send + 'static,
|
||||
{
|
||||
let job = Box::new(f);
|
||||
|
||||
// commit job to sender object --> pass to threads for execution
|
||||
self.sender.as_ref().unwrap().send(job).unwrap();
|
||||
}
|
||||
}
|
||||
|
||||
impl Drop for ThreadPool {
|
||||
fn drop(&mut self) {
|
||||
// drop sender first
|
||||
drop(self.sender.take());
|
||||
|
||||
// then drop workers
|
||||
for worker in &mut self.workers {
|
||||
println!("Shutting down worker {}", worker.id);
|
||||
|
||||
// join worker thread
|
||||
if let Some(thread) = worker.thread.take() {
|
||||
thread.join().unwrap();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
struct Worker {
|
||||
id: usize,
|
||||
thread: Option<thread::JoinHandle<()>>,
|
||||
}
|
||||
|
||||
impl Worker {
|
||||
/// Create a new Worker..
|
||||
///
|
||||
/// The id is a unique identifier.
|
||||
/// The receiver is a shared pointer to a receiver protected by Mutex.
|
||||
fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
|
||||
// spawn thread and enter infinite loop
|
||||
let thread = thread::spawn(move || loop {
|
||||
// lock mutex and wait for job
|
||||
let message = receiver.lock().unwrap().recv();
|
||||
|
||||
match message {
|
||||
// normal operation --> execute job
|
||||
Ok(job) => {
|
||||
println!("Worker {id} got a job; executing.");
|
||||
|
||||
job();
|
||||
}
|
||||
// exit gracefully when pool is closed --> recv will return error then
|
||||
Err(_) => {
|
||||
println!("Worker {id} disconnected; shutting down.");
|
||||
break;
|
||||
}
|
||||
}
|
||||
});
|
||||
|
||||
Worker {
|
||||
id,
|
||||
thread: Some(thread),
|
||||
}
|
||||
}
|
||||
}
|
Loading…
x
Reference in New Issue
Block a user