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
use core::Flush;
use core::attributes::{Attributes, WithAttributes, Prefixed};
use core::name::MetricName;
use core::output::{Output, OutputMetric, OutputScope, OutputDyn};
use core::input::InputKind;
use cache::lru_cache as lru;
use core::error;
use std::sync::{Arc, RwLock};
use std::rc::Rc;
pub trait CachedOutput: Output + Send + Sync + 'static + Sized {
fn cached(self, max_size: usize) -> OutputCache {
OutputCache::wrap(self, max_size)
}
}
#[derive(Clone)]
pub struct OutputCache {
attributes: Attributes,
target: Arc<OutputDyn + Send + Sync + 'static>,
cache: Arc<RwLock<lru::LRUCache<MetricName, OutputMetric>>>,
}
impl OutputCache {
pub fn wrap<OUT: Output + Send + Sync + 'static>(target: OUT, max_size: usize) -> OutputCache {
OutputCache {
attributes: Attributes::default(),
target: Arc::new(target),
cache: Arc::new(RwLock::new(lru::LRUCache::with_capacity(max_size)))
}
}
}
impl WithAttributes for OutputCache {
fn get_attributes(&self) -> &Attributes { &self.attributes }
fn mut_attributes(&mut self) -> &mut Attributes { &mut self.attributes }
}
impl Output for OutputCache {
type SCOPE = OutputScopeCache;
fn output(&self) -> Self::SCOPE {
let target = self.target.output_dyn();
OutputScopeCache {
attributes: self.attributes.clone(),
target,
cache: self.cache.clone(),
}
}
}
#[derive(Clone)]
pub struct OutputScopeCache {
attributes: Attributes,
target: Rc<OutputScope + 'static>,
cache: Arc<RwLock<lru::LRUCache<MetricName, OutputMetric>>>,
}
impl WithAttributes for OutputScopeCache {
fn get_attributes(&self) -> &Attributes { &self.attributes }
fn mut_attributes(&mut self) -> &mut Attributes { &mut self.attributes }
}
impl OutputScope for OutputScopeCache {
fn new_metric(&self, name: MetricName, kind: InputKind) -> OutputMetric {
let name = self.prefix_append(name);
let lookup = {
self.cache.write().expect("Cache Lock").get(&name).cloned()
};
lookup.unwrap_or_else(|| {
let new_metric: OutputMetric = self.target.new_metric(name.clone(), kind);
let mut cache_miss = self.cache.write().expect("Cache Lock");
cache_miss.insert(name, new_metric.clone());
new_metric
})
}
}
impl Flush for OutputScopeCache {
fn flush(&self) -> error::Result<()> {
self.target.flush()
}
}