quota 0.1.9

High-performance Rate-limiter
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

use crate::{Quota, QuotaPolicy, QuotaResult};
use dashmap::DashMap;
use parking_lot::Mutex;
use std::borrow::Borrow;
use std::hash::Hash;
use std::time::Instant;

pub type QuotaKey = String;

pub struct QuotaPool<K = QuotaKey>
where
    K: Eq + Hash,
{
    initial_available_tokens: u64,
    policy: QuotaPolicy,
    entries: DashMap<K, Mutex<QuotaSlot>>,
    epoch: Instant,
}

struct QuotaSlot {
    quota: Quota,
    last_access_time_ns: u64,
    last_refill_time_ns: u64,
}

impl QuotaSlot {
    #[inline]
    fn new(initial_available_tokens: u64) -> Self {
        Self {
            quota: Quota::with_initial_tokens(initial_available_tokens),
            last_access_time_ns: 0,
            last_refill_time_ns: 0,
        }
    }

    #[inline]
    fn consume(&mut self, policy: &QuotaPolicy, now_ns: u64, cost: u64) -> QuotaResult {
        let delta_ns = now_ns.saturating_sub(self.last_access_time_ns);
        self.last_access_time_ns = now_ns;

        let elapsed_since_refill_ns = now_ns.saturating_sub(self.last_refill_time_ns);
        let did_refill = policy.tick_with_interval(delta_ns, &self.quota, elapsed_since_refill_ns);

        if did_refill {
            self.last_refill_time_ns = now_ns;
        }

        self.quota.consume(cost)
    }
}

impl QuotaPool {
    #[inline]
    pub fn new(policy: QuotaPolicy, initial_available_tokens: u64) -> Self {
        Self::with_key_type(policy, initial_available_tokens)
    }
}

impl<K: Eq + Hash> QuotaPool<K> {
    #[inline]
    pub fn with_key_type(policy: QuotaPolicy, initial_available_tokens: u64) -> Self {
        Self::with_capacity(policy, initial_available_tokens, 0)
    }

    #[inline]
    pub fn with_capacity(
        policy: QuotaPolicy,
        initial_available_tokens: u64,
        capacity: usize,
    ) -> Self {
        Self {
            initial_available_tokens,
            policy,
            entries: DashMap::with_capacity(capacity),
            epoch: Instant::now(),
        }
    }

    #[inline]
    pub fn len(&self) -> usize {
        self.entries.len()
    }

    #[inline]
    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }

    #[inline]
    pub fn contains_key<Q>(&self, key: &Q) -> bool
    where
        K: Borrow<Q>,
        Q: Eq + Hash + ?Sized,
    {
        self.entries.contains_key(key)
    }

    #[inline]
    pub fn insert_keys<'a, Q, I>(&self, keys: I)
    where
        K: Borrow<Q>,
        Q: Eq + Hash + ToOwned<Owned = K> + ?Sized + 'a,
        I: IntoIterator<Item = &'a Q>,
    {
        for key in keys {
            self.insert_key(key);
        }
    }

    #[inline]
    pub fn insert_key<Q>(&self, key: &Q)
    where
        K: Borrow<Q>,
        Q: Eq + Hash + ToOwned<Owned = K> + ?Sized,
    {
        if self.entries.get(key).is_some() {
            return;
        }

        self.entries
            .entry(key.to_owned())
            .or_insert_with(|| Mutex::new(QuotaSlot::new(self.initial_available_tokens)));
    }

    #[inline]
    pub fn consume<Q>(&self, key: &Q, cost: u64) -> QuotaResult
    where
        K: Borrow<Q>,
        Q: Eq + Hash + ToOwned<Owned = K> + ?Sized,
    {
        if let Some(entry) = self.entries.get(key) {
            return self.consume_slot(&entry, cost);
        }

        let entry = self
            .entries
            .entry(key.to_owned())
            .or_insert_with(|| Mutex::new(QuotaSlot::new(self.initial_available_tokens)));

        self.consume_slot(&entry, cost)
    }

    #[inline]
    pub fn consume_owned(&self, key: K, cost: u64) -> QuotaResult {
        if let Some(entry) = self.entries.get(&key) {
            return self.consume_slot(&entry, cost);
        }

        let entry = self
            .entries
            .entry(key)
            .or_insert_with(|| Mutex::new(QuotaSlot::new(self.initial_available_tokens)));

        self.consume_slot(&entry, cost)
    }

    #[inline]
    fn consume_slot(&self, slot: &Mutex<QuotaSlot>, cost: u64) -> QuotaResult {
        let mut slot = slot.lock();
        let now_ns = self.epoch.elapsed().as_nanos() as u64;
        slot.consume(&self.policy, now_ns, cost)
    }
}

#[cfg(test)]
mod tests;