I was wondering how can I pass any variabel that did not implement Copy trait;

[rockburning]

source code

#[derive(Clone,)]
pub struct TaskTest{
    id: String
}

#[async_trait::async_trait]
impl PodProcessor for TaskTest{
    async fn process(&mut  self, id: &str)->anyhow::Result<()> {
        println!("hell  {}",id.to_string());
        Ok(())
    }
}

#[tokio::main]
async fn main() -> Result<(), JobSchedulerError> {
    let mut sched = JobScheduler::new().await?;

    // Add basic cron job
   let s = "32".to_string() ;
    let s_clone = s.clone();
    let mut handle = TaskTest {
        id: "".to_string(),
    };

    // let processor = Arc::new(handle) as Arc<dyn PodProcessor>;
    // let proc_clone = processor.clone();
    // let handle = proc_clone.clone().process(Arc::new(s));
    sched.add(
        Job::new_async("1/7 * * * * *", move |uuid, mut l| {
            Box::pin(async move {
                handle.process("123").await;
            })
        })?
    ).await?;

    // Start the scheduler
    sched.start().await?;

    // Wait while the jobs run
    tokio::time::sleep(Duration::from_secs(100)).await;

    Ok(())
}

ERRO is

296	Job::new_async("1/7 *", move	uuid, mut l	{	------------------ captured by this FnMut closure 297	Box::pin(async move {	__^ 298		handle.process("123").await;
	variable moved due to use in coroutine
	move occurs because handle has type TaskTest, which does not implement the Copy trait
299		})
	_____^ handle is moved here

[rockburning]

as shown in the above; my struct TaskTest has its own attribute id is string which is common type in strcut; when I want to capture it in the clousure it show the error above;

[mvniekerk]

Hi @rockburning Thank you for the reporting the issue.

We're using Tokio, this uses "task stealing" in terms of how it does async sheduling. That means, a task can move between threads. For Tokio, the struct being passed on should be implementing Copy. Some other async schedulers doesn't use task stealing, which removes the need of Copy.

That means, in practice, that you'll need to either resort to .clones() or to things that use Arc<RwLock<_>> in order to sync sending these structs over threads.

Sorry, this is Rust's fearless concurrency hitting you with this issue.

[mvniekerk]

For references: https://users.rust-lang.org/t/help-with-tokio-rwlock-and-the-copy-trait/48486 https://users.rust-lang.org/t/how-to-pass-struct-to-other-function-that-use-tokio-without-copy-trait/103775/6

Yeah there's plenty of people hitting the same issue.

Feel free to re-open this issue if you think we should handle this differently?