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

use crate::{
    JobStatus, PidController, TickWorkTracker, WorkerPool, WorkerPoolCommand, WorkerPoolStatus,
};

use async_std::future::Future;

use log::debug;

use async_std::{
    pin::Pin,
    stream::Stream,
    task::{Context, Poll},
};
use std::time::Duration;

pub struct AutoPool<In, Out, F> {
    /// WorkerPool to drive and monitor
    pool: WorkerPool<In, Out, F>,
    /// Current number
    num_workers: f32,
    /// Three part controller that drives towards the target rate
    pid: PidController,
    /// Work tracking
    tracker: TickWorkTracker,
    /// User controlled settings
    config: AutoPoolConfig,
}

pub struct AutoPoolConfig {
    /// How often to evaluate the PID controller and add/remove workers
    tick_rate: Duration,
    /// Target executions per second across all workers
    goal_rate_per_sec: f32,
}

impl<In, Out, F> AutoPool<In, Out, F>
where
    In: Send + Sync + Clone + 'static,
    Out: Send + Sync + 'static,
    F: Future<Output = JobStatus> + Send + 'static,
{
    pub fn new(config: AutoPoolConfig, pool: WorkerPool<In, Out, F>) -> Self {
        Self {
            tracker: TickWorkTracker::new(config.tick_rate),
            pid: Default::default(), // todo PidConfig
            num_workers: 0.0,
            config,
            pool,
        }
    }

    fn work(&mut self) -> WorkerPoolStatus<Out> {
        self.tick();

        match self.pool.work() {
            WorkerPoolStatus::Ready(out) => {
                self.tracker.track_work();
                return WorkerPoolStatus::Ready(out);
            }
            WorkerPoolStatus::Working => WorkerPoolStatus::Working,
            WorkerPoolStatus::Done => WorkerPoolStatus::Done,
        }
    }

    fn tick(&mut self) {
        if !self.tracker.tick_done() {
            return;
        }

        debug!("{}, {}, {}", self.pid.output(), self.tracker.tick_rate_per_sec(), self.num_workers);

        self.pid.update(self.config.goal_rate_per_sec, self.tracker.tick_rate_per_sec());
        self.num_workers += self.pid.output();

        // Update workers if we've crossed over an integer threshold
        if self.num_workers.floor() as usize != self.pool.target_workers() {
            self.pool.command(WorkerPoolCommand::SetWorkerCount(self.num_workers as usize));
        }
    }
}

impl<In, Out, F> Stream for AutoPool<In, Out, F>
where
    In: Send + Sync + Unpin + Clone + 'static,
    Out: Send + Sync + Unpin + 'static,
    F: Future<Output = JobStatus> + Send + 'static,
{
    type Item = Out;

    fn poll_next(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        dbg!("YOOO");
        match self.get_mut().work() {
            WorkerPoolStatus::Ready(o) => Poll::Ready(Some(o)),
            WorkerPoolStatus::Working => Poll::Pending,
            WorkerPoolStatus::Done => Poll::Ready(None),
        }
    }
}

impl AutoPoolConfig {
    pub fn new(tick_rate: Duration, goal_rate_per_sec: f32) -> Self {
        Self { tick_rate, goal_rate_per_sec }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{pool::WorkerPoolConfig, Job};
    use async_std::task;
    use futures_await_test::async_test;
    use std::time::Duration;

    /// Double the input some number of times or until we receive a close message
    async fn double(job: Job<(usize, usize), usize>) -> JobStatus {
        let (mut i, n) = job.task;
        for _ in 0..n {
            // play nice with the pool by allowing it to stop this loop early
            if job.stop_requested() {
                break;
            }

            // do the actual work
            i *= 2;

            // send it to the pool for collection so it can be sent along to listeners
            job.results.send(i).await;

            // pretend this is hard
            task::sleep(Duration::from_millis(100)).await;
        }

        JobStatus::Done
    }

    #[async_test]
    async fn autopool_new() {
        let wp_config = *WorkerPoolConfig::new().target_workers(4).default_job((2, 10));
        let ap_config = AutoPoolConfig::new(Duration::from_secs_f32(0.1), 2500.0);
        let worker_pool = WorkerPool::new_with_config(double, wp_config);

        let _auto_pool = AutoPool::new(ap_config, worker_pool);
    }
}