accelerator 0.1.1

MVP multi-level cache runtime with singleflight load de-duplication
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

use accelerator::CacheError;

use crate::support::{CacheableBatchHarness, MacroTestError, User};

#[tokio::test]
async fn cacheable_batch_merges_cache_hit_and_load_miss() {
    let harness = CacheableBatchHarness::new();
    harness.cache.seed(
        1,
        Some(User {
            id: 1,
            name: "cached-1".to_string(),
        }),
    );

    let values = harness.load_users(vec![1, 2, 4]).await.unwrap();

    assert_eq!(
        values.get(&1).cloned().unwrap(),
        Some(User {
            id: 1,
            name: "cached-1".to_string()
        })
    );
    assert_eq!(
        values.get(&2).cloned().unwrap(),
        Some(User {
            id: 2,
            name: "u2".to_string()
        })
    );
    assert_eq!(values.get(&4).cloned().unwrap(), None);
    assert_eq!(harness.load_inputs(), vec![vec![2, 4]]);
    assert_eq!(harness.cache.mget_calls(), 1);
    assert_eq!(harness.cache.mset_calls(), 1);
    assert_eq!(harness.cache.last_mset_sizes(), vec![2]);
}

#[tokio::test]
async fn cacheable_batch_deduplicates_duplicate_keys() {
    let harness = CacheableBatchHarness::new();

    let values = harness.load_users(vec![2, 2, 2, 3, 3]).await.unwrap();

    assert_eq!(values.len(), 2);
    assert_eq!(
        values.get(&2).cloned().unwrap(),
        Some(User {
            id: 2,
            name: "u2".to_string()
        })
    );
    assert_eq!(
        values.get(&3).cloned().unwrap(),
        Some(User {
            id: 3,
            name: "u3".to_string()
        })
    );
    assert_eq!(harness.load_inputs(), vec![vec![2, 3]]);
}

#[tokio::test]
async fn cacheable_batch_empty_input_short_circuits() {
    let harness = CacheableBatchHarness::new();

    let values = harness.load_users(Vec::new()).await.unwrap();

    assert!(values.is_empty());
    assert_eq!(harness.load_inputs().len(), 0);
    assert_eq!(harness.cache.mget_calls(), 0);
    assert_eq!(harness.cache.mset_calls(), 0);
}

#[tokio::test]
async fn cacheable_batch_ignore_mget_error_keeps_business_flow() {
    let harness = CacheableBatchHarness::new();
    harness.cache.set_fail_mget(true);

    let values = harness.load_users(vec![1, 2]).await.unwrap();

    assert_eq!(
        values.get(&1).cloned().unwrap(),
        Some(User {
            id: 1,
            name: "u1".to_string()
        })
    );
    assert_eq!(
        values.get(&2).cloned().unwrap(),
        Some(User {
            id: 2,
            name: "u2".to_string()
        })
    );
    assert_eq!(harness.load_inputs(), vec![vec![1, 2]]);
}

#[tokio::test]
async fn cacheable_batch_propagate_mget_error_returns_cache_error() {
    let harness = CacheableBatchHarness::new();
    harness.cache.set_fail_mget(true);

    let err = harness.load_users_propagate(vec![1, 2]).await.unwrap_err();

    assert!(matches!(
        err,
        MacroTestError::Cache(CacheError::Backend(ref msg)) if msg.contains("mock mget failed")
    ));
    assert_eq!(harness.load_inputs().len(), 0);
}

#[tokio::test]
async fn cacheable_batch_propagate_mset_error_returns_cache_error() {
    let harness = CacheableBatchHarness::new();
    harness.cache.set_fail_mset(true);

    let err = harness.load_users_propagate(vec![2, 3]).await.unwrap_err();

    assert!(matches!(
        err,
        MacroTestError::Cache(CacheError::Backend(ref msg)) if msg.contains("mock mset failed")
    ));
    assert_eq!(harness.load_inputs(), vec![vec![2, 3]]);
    assert_eq!(harness.cache.mset_calls(), 1);
}

#[tokio::test]
async fn cacheable_batch_business_error_is_returned_and_skips_mset() {
    let harness = CacheableBatchHarness::new();

    let err = harness.load_users_fail(vec![1, 2]).await.unwrap_err();

    assert!(matches!(err, MacroTestError::Biz("batch-load-failed")));
    assert_eq!(harness.load_inputs(), vec![vec![1, 2]]);
    assert_eq!(harness.cache.mset_calls(), 0);
}