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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
use std::time::{Duration, Instant};
use async_trait::async_trait;
use futures::future::*;
use futures::stream::FuturesUnordered;
use futures::StreamExt;
use tokio::select;
use tokio::sync::{mpsc, watch};
use tracing::*;
use crate::error::Error;
#[derive(PartialEq, Copy, Clone, Debug)]
pub enum WorkerStatus {
Busy,
Idle,
Done,
}
#[async_trait]
pub trait Worker: Send {
fn name(&self) -> String;
/// Work: do a basic unit of work, if one is available (otherwise, should return
/// WorkerStatus::Idle immediately). We will do our best to not interrupt this future in the
/// middle of processing, it will only be interrupted at the last minute when Garage is trying
/// to exit and this hasn't returned yet. This function may return an error to indicate that
/// its unit of work could not be processed due to an error: the error will be logged and
/// .work() will be called again immediately.
async fn work(&mut self, must_exit: &mut watch::Receiver<bool>) -> Result<WorkerStatus, Error>;
/// Wait for work: await for some task to become available. This future can be interrupted in
/// the middle for any reason. This future doesn't have to await on must_exit.changed(), we
/// are doing it for you. Therefore it only receives a read refernce to must_exit which allows
/// it to check if we are exiting.
async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerStatus;
}
pub(crate) struct WorkerProcessor {
stop_signal: watch::Receiver<bool>,
worker_chan: mpsc::UnboundedReceiver<Box<dyn Worker>>,
}
impl WorkerProcessor {
pub(crate) fn new(
worker_chan: mpsc::UnboundedReceiver<Box<dyn Worker>>,
stop_signal: watch::Receiver<bool>,
) -> Self {
Self {
stop_signal,
worker_chan,
}
}
pub(crate) async fn run(&mut self) {
let mut workers = FuturesUnordered::new();
let mut next_task_id = 1;
while !*self.stop_signal.borrow() {
let await_next_worker = async {
if workers.is_empty() {
futures::future::pending().await
} else {
workers.next().await
}
};
select! {
new_worker_opt = self.worker_chan.recv() => {
if let Some(new_worker) = new_worker_opt {
let task_id = next_task_id;
next_task_id += 1;
let stop_signal = self.stop_signal.clone();
let stop_signal_worker = self.stop_signal.clone();
workers.push(async move {
let mut worker = WorkerHandler {
task_id,
stop_signal,
stop_signal_worker,
worker: new_worker,
status: WorkerStatus::Busy,
};
worker.step().await;
worker
}.boxed());
}
}
worker = await_next_worker => {
if let Some(mut worker) = worker {
// TODO save new worker status somewhere
if worker.status == WorkerStatus::Done {
info!("Worker {} (TID {}) exited", worker.worker.name(), worker.task_id);
} else {
workers.push(async move {
worker.step().await;
worker
}.boxed());
}
}
}
_ = self.stop_signal.changed() => (),
}
}
// We are exiting, drain everything
let drain_half_time = Instant::now() + Duration::from_secs(5);
let drain_everything = async move {
while let Some(mut worker) = workers.next().await {
if worker.status == WorkerStatus::Done {
info!(
"Worker {} (TID {}) exited",
worker.worker.name(),
worker.task_id
);
} else if Instant::now() > drain_half_time {
warn!("Worker {} (TID {}) interrupted between two iterations in state {:?} (this should be fine)", worker.worker.name(), worker.task_id, worker.status);
} else {
workers.push(
async move {
worker.step().await;
worker
}
.boxed(),
);
}
}
};
select! {
_ = drain_everything => {
info!("All workers exited in time \\o/");
}
_ = tokio::time::sleep(Duration::from_secs(9)) => {
error!("Some workers could not exit in time, we are cancelling some things in the middle");
}
}
}
}
// TODO add tranquilizer
struct WorkerHandler {
task_id: usize,
stop_signal: watch::Receiver<bool>,
stop_signal_worker: watch::Receiver<bool>,
worker: Box<dyn Worker>,
status: WorkerStatus,
}
impl WorkerHandler {
async fn step(&mut self) {
match self.status {
WorkerStatus::Busy => match self.worker.work(&mut self.stop_signal).await {
Ok(s) => {
self.status = s;
}
Err(e) => {
error!(
"Error in worker {} (TID {}): {}",
self.worker.name(),
self.task_id,
e
);
}
},
WorkerStatus::Idle => {
if *self.stop_signal.borrow() {
select! {
new_st = self.worker.wait_for_work(&mut self.stop_signal_worker) => {
self.status = new_st;
}
_ = tokio::time::sleep(Duration::from_secs(1)) => {
// stay in Idle state
}
}
} else {
select! {
new_st = self.worker.wait_for_work(&mut self.stop_signal_worker) => {
self.status = new_st;
}
_ = self.stop_signal.changed() => {
// stay in Idle state
}
}
}
}
WorkerStatus::Done => unreachable!(),
}
}
}
|
