logforth_append_fastrace/
lib.rs

1// Copyright 2024 FastLabs Developers
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Appender for integrating with [fastrace](https://crates.io/crates/fastrace).
16
17#![cfg_attr(docsrs, feature(doc_cfg))]
18
19use std::borrow::Cow;
20
21use jiff::Zoned;
22use logforth_core::Diagnostic;
23use logforth_core::Error;
24use logforth_core::append::Append;
25use logforth_core::kv::Key;
26use logforth_core::kv::Value;
27use logforth_core::kv::Visitor;
28use logforth_core::record::Record;
29
30/// An appender that adds log records to fastrace as an event associated to the current span.
31///
32/// # Examples
33///
34/// ```
35/// use logforth_append_fastrace::FastraceEvent;
36///
37/// let fastrace_appender = FastraceEvent::default();
38/// ```
39#[derive(Default, Debug, Clone)]
40#[non_exhaustive]
41pub struct FastraceEvent {}
42
43impl Append for FastraceEvent {
44    fn append(&self, record: &Record, diags: &[Box<dyn Diagnostic>]) -> Result<(), Error> {
45        let message = record.payload().to_owned();
46
47        let mut collector = KvCollector { kv: Vec::new() };
48        record.key_values().visit(&mut collector)?;
49        for d in diags {
50            d.visit(&mut collector)?;
51        }
52
53        fastrace::local::LocalSpan::add_event(fastrace::Event::new(message).with_properties(
54            || {
55                [
56                    (Cow::from("level"), Cow::from(record.level().as_str())),
57                    (Cow::from("timestamp"), Cow::from(Zoned::now().to_string())),
58                ]
59                .into_iter()
60                .chain(
61                    collector
62                        .kv
63                        .into_iter()
64                        .map(|(k, v)| (Cow::from(k), Cow::from(v))),
65                )
66            },
67        ));
68
69        Ok(())
70    }
71
72    fn flush(&self) -> Result<(), Error> {
73        fastrace::flush();
74        Ok(())
75    }
76
77    fn exit(&self) -> Result<(), Error> {
78        // fastrace flush accesses thread-local storage,
79        // which is not supported in atexit handlers
80        Ok(())
81    }
82}
83
84struct KvCollector {
85    kv: Vec<(String, String)>,
86}
87
88impl Visitor for KvCollector {
89    fn visit(&mut self, key: Key, value: Value) -> Result<(), Error> {
90        self.kv.push((key.to_string(), value.to_string()));
91        Ok(())
92    }
93}
logforth_append_fastrace/lib.rs

logforth_append_fastrace/
lib.rs
