pingora-cache 0.8.0

HTTP caching APIs for Pingora proxy.
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

// Copyright 2026 Cloudflare, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Distributed tracing helpers

use cf_rustracing_jaeger::span::SpanContextState;
use std::time::SystemTime;

use crate::{CacheMeta, CachePhase, HitStatus};

pub use cf_rustracing::tag::Tag;

pub type Span = cf_rustracing::span::Span<SpanContextState>;
pub type SpanHandle = cf_rustracing::span::SpanHandle<SpanContextState>;

#[derive(Debug)]
pub(crate) struct CacheTraceCTX {
    // parent span
    pub cache_span: Span,
    // only spans across multiple calls need to store here
    pub miss_span: Span,
    pub hit_span: Span,
}

pub fn tag_span_with_meta(span: &mut Span, meta: &CacheMeta) {
    fn ts2epoch(ts: SystemTime) -> f64 {
        ts.duration_since(SystemTime::UNIX_EPOCH)
            .unwrap_or_default() // should never overflow but be safe here
            .as_secs_f64()
    }
    let internal = &meta.0.internal;
    span.set_tags(|| {
        [
            Tag::new("created", ts2epoch(internal.created)),
            Tag::new("fresh_until", ts2epoch(internal.fresh_until)),
            Tag::new("updated", ts2epoch(internal.updated)),
            Tag::new("stale_if_error_sec", internal.stale_if_error_sec as i64),
            Tag::new(
                "stale_while_revalidate_sec",
                internal.stale_while_revalidate_sec as i64,
            ),
            Tag::new("variance", internal.variance.is_some()),
        ]
    });
}

impl CacheTraceCTX {
    pub fn new() -> Self {
        CacheTraceCTX {
            cache_span: Span::inactive(),
            miss_span: Span::inactive(),
            hit_span: Span::inactive(),
        }
    }

    pub fn enable(&mut self, cache_span: Span) {
        self.cache_span = cache_span;
    }

    pub fn get_cache_span(&self) -> SpanHandle {
        self.cache_span.handle()
    }

    #[inline]
    pub fn child(&self, name: &'static str) -> Span {
        self.cache_span.child(name, |o| o.start())
    }

    pub fn start_miss_span(&mut self) {
        self.miss_span = self.child("miss");
    }

    pub fn get_miss_span(&self) -> SpanHandle {
        self.miss_span.handle()
    }

    pub fn finish_miss_span(&mut self) {
        self.miss_span.set_finish_time(SystemTime::now);
    }

    pub fn start_hit_span(&mut self, phase: CachePhase, hit_status: HitStatus) {
        self.hit_span = self.child("hit");
        self.hit_span.set_tag(|| Tag::new("phase", phase.as_str()));
        self.hit_span
            .set_tag(|| Tag::new("status", hit_status.as_str()));
    }

    pub fn get_hit_span(&self) -> SpanHandle {
        self.hit_span.handle()
    }

    pub fn finish_hit_span(&mut self) {
        self.hit_span.set_finish_time(SystemTime::now);
    }

    pub fn log_meta_in_hit_span(&mut self, meta: &CacheMeta) {
        tag_span_with_meta(&mut self.hit_span, meta);
    }

    pub fn log_meta_in_miss_span(&mut self, meta: &CacheMeta) {
        tag_span_with_meta(&mut self.miss_span, meta);
    }
}