# Task Execution Queue
*Task Execution Queue* 一个任务执行队列。可限制任务并发执行数量,可控制同一类任务执行顺序。通常,异步任务直接使用Tokio或async-std执行即可;
但是,某些特殊业务场景我们需要批量执行任务,又要控制任务的并发数量时,直接使用spawn()容易导致负载过大,CPU或内存等资源耗尽;此Crate就是为了解决此 类问题而开发的。
## 功能特色
- 可执行任务;
- 可执行任务并返回结果;
- 可限制并发执行任务数量;
- 任务队列;
- 同一类任务顺序执行;
- 支持Local任务
## 计划
## 例子
- quick start
```rust
fn main() {
use async_std::task::spawn;
use rust_box::task_exec_queue::{init_default, default, SpawnDefaultExt};
let task_runner = init_default();
let root_fut = async move {
spawn(async {
//start executor
task_runner.await;
});
//execute task ...
let _ = async {
println!("hello world!");
}.spawn().await;
default().flush().await;
};
async_std::task::block_on(root_fut);
}
```
- execute and return result
```rust
fn main() {
use async_std::task::spawn;
use rust_box::task_exec_queue::{Builder, SpawnExt};
let (exec, task_runner) = Builder::default().workers(10).queue_max(100).build();
let root_fut = async move {
spawn(async {
//start executor
task_runner.await;
});
//execute task and return result...
let res = async {
"hello world!"
}.spawn(&exec).result().await;
println!("result: {:?}", res.ok());
exec.flush().await;
};
async_std::task::block_on(root_fut);
}
```
- sequential execution
```rust
fn main() {
use async_std::task::spawn;
use rust_box::task_exec_queue::{Builder, SpawnExt};
let (exec, task_runner) =
Builder::default().workers(10).queue_max(100).group().build::<&str>();
let root_fut = async move {
spawn(async {
//start executor
task_runner.await;
});
//execute task ...
let _res = async move {
println!("hello world!");
}.spawn(&exec).group("g1").await;
let res = async move {
"hello world!"
}.spawn(&exec).group("g1").result().await;
println!("result: {:?}", res.ok());
exec.flush().await;
println!("exec.actives: {}, waitings: {}, completeds: {}", exec.active_count(), exec.waiting_count(), exec.completed_count());
};
async_std::task::block_on(root_fut);
}
```
### 更多例子
- [task-exec-queue-test.rs](https://github.com/try-box/rust-box/blob/main/examples/src/task-exec-queue-test.rs)