jaeb 0.3.9

simple snapshot-driven event bus
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
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

use std::sync::Arc;
use std::sync::Mutex;
use std::sync::atomic::{AtomicUsize, Ordering};

use jaeb::{EventBus, EventHandler, HandlerResult, SubscriptionPolicy, SyncEventHandler, SyncSubscriptionPolicy};

#[derive(Clone)]
struct PriorityEvent;

struct OrderedSync {
    id: usize,
    order: Arc<Mutex<Vec<usize>>>,
}

impl SyncEventHandler<PriorityEvent> for OrderedSync {
    fn handle(&self, _event: &PriorityEvent) -> HandlerResult {
        let mut guard = self.order.lock().expect("lock order");
        guard.push(self.id);
        Ok(())
    }
}

struct OrderedAsync {
    id: usize,
    order: Arc<Mutex<Vec<usize>>>,
    hits: Arc<AtomicUsize>,
}

impl EventHandler<PriorityEvent> for OrderedAsync {
    async fn handle(&self, _event: &PriorityEvent) -> HandlerResult {
        self.hits.fetch_add(1, Ordering::SeqCst);
        let mut guard = self.order.lock().expect("lock order");
        guard.push(self.id);
        Ok(())
    }
}

#[tokio::test]
async fn sync_priority_orders_high_to_low() {
    let bus = EventBus::new(64).expect("valid config");
    let order = Arc::new(Mutex::new(Vec::new()));

    let low = SyncSubscriptionPolicy::default().with_priority(-10);
    let mid = SyncSubscriptionPolicy::default().with_priority(0);
    let high = SyncSubscriptionPolicy::default().with_priority(10);

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 1,
                order: Arc::clone(&order),
            },
            low,
        )
        .await
        .expect("subscribe low");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 2,
                order: Arc::clone(&order),
            },
            high,
        )
        .await
        .expect("subscribe high");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 3,
                order: Arc::clone(&order),
            },
            mid,
        )
        .await
        .expect("subscribe mid");

    bus.publish(PriorityEvent).await.expect("publish");
    bus.shutdown().await.expect("shutdown");

    let got = order.lock().expect("lock order").clone();
    assert_eq!(got, vec![2, 3, 1]);
}

#[tokio::test]
async fn sync_equal_priority_keeps_fifo_order() {
    let bus = EventBus::new(64).expect("valid config");
    let order = Arc::new(Mutex::new(Vec::new()));

    let p = SyncSubscriptionPolicy::default().with_priority(7);

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 1,
                order: Arc::clone(&order),
            },
            p,
        )
        .await
        .expect("subscribe 1");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 2,
                order: Arc::clone(&order),
            },
            p,
        )
        .await
        .expect("subscribe 2");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedSync {
                id: 3,
                order: Arc::clone(&order),
            },
            p,
        )
        .await
        .expect("subscribe 3");

    bus.publish(PriorityEvent).await.expect("publish");
    bus.shutdown().await.expect("shutdown");

    let got = order.lock().expect("lock order").clone();
    assert_eq!(got, vec![1, 2, 3]);
}

#[tokio::test]
async fn async_priority_orders_spawn_sequence() {
    let bus = EventBus::builder().buffer_size(64).max_concurrent_async(1).build().expect("valid config");

    let order = Arc::new(Mutex::new(Vec::new()));
    let hits = Arc::new(AtomicUsize::new(0));

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedAsync {
                id: 1,
                order: Arc::clone(&order),
                hits: Arc::clone(&hits),
            },
            SubscriptionPolicy::default().with_priority(-1),
        )
        .await
        .expect("subscribe low");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedAsync {
                id: 2,
                order: Arc::clone(&order),
                hits: Arc::clone(&hits),
            },
            SubscriptionPolicy::default().with_priority(20),
        )
        .await
        .expect("subscribe high");

    let _ = bus
        .subscribe_with_policy::<PriorityEvent, _, _>(
            OrderedAsync {
                id: 3,
                order: Arc::clone(&order),
                hits: Arc::clone(&hits),
            },
            SubscriptionPolicy::default().with_priority(0),
        )
        .await
        .expect("subscribe mid");

    bus.publish(PriorityEvent).await.expect("publish");
    bus.shutdown().await.expect("shutdown");

    assert_eq!(hits.load(Ordering::SeqCst), 3);
    let got = order.lock().expect("lock order").clone();
    assert_eq!(got, vec![2, 3, 1]);
}