tender 0.1.1

A Raft-based election framework
Documentation 
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

use crate::{ElectionType, State};
use std::time::SystemTime;
use watch::{WatchReceiver, WatchSender};

/// A set of metrics describing the current state of election.
#[derive(Clone)]
pub struct Metrics<T: ElectionType> {
    /// The state of the node.
    pub state: State,
    /// Current term of the node.
    pub current_term: u64,
    /// Current leader of the group.
    pub current_leader: Option<T::NodeId>,
    /// The last time a heartbeat was received.
    pub last_heartbeat_time: Option<SystemTime>,
}

impl<T: ElectionType> Metrics<T> {
    #[inline]
    pub(crate) fn new() -> Self {
        Metrics {
            state: State::Startup,
            current_term: 0,
            current_leader: None,
            last_heartbeat_time: None,
        }
    }
}

pub(crate) struct MetricsReporter<T: ElectionType> {
    metrics_tx: WatchSender<Metrics<T>>,
}

impl<T: ElectionType> MetricsReporter<T> {
    #[inline]
    pub(crate) fn new(metrics_tx: WatchSender<Metrics<T>>) -> Self {
        MetricsReporter { metrics_tx }
    }

    #[inline]
    pub(crate) fn report(&mut self, metrics: Metrics<T>) {
        self.metrics_tx.send(metrics);
    }

    #[inline]
    pub(crate) fn update<F>(&mut self, f: F)
    where
        F: FnOnce(&mut Metrics<T>),
    {
        self.metrics_tx.update(f)
    }
}

/// The metrics watcher of the node.
#[derive(Clone)]
pub struct MetricsWatcher<T: ElectionType> {
    metrics_rx: WatchReceiver<Metrics<T>>,
}

impl<T: ElectionType> MetricsWatcher<T> {
    #[inline]
    pub(crate) fn new(metrics_rx: WatchReceiver<Metrics<T>>) -> Self {
        MetricsWatcher { metrics_rx }
    }

    /// A set of metrics describing the current state of the node.
    #[inline]
    pub fn metrics(&mut self) -> Metrics<T> {
        self.metrics_rx.get()
    }
}

#[inline]
pub(crate) fn metrics_channel<T: ElectionType>() -> (MetricsReporter<T>, MetricsWatcher<T>) {
    let (tx, rx) = watch::channel(Metrics::new());
    (MetricsReporter::new(tx), MetricsWatcher::new(rx))
}