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#![deny(missing_docs)]
19
20use std::borrow::Cow;
21
22use jiff::Zoned;
23use logforth_core::Diagnostic;
24use logforth_core::Error;
25use logforth_core::append::Append;
26use logforth_core::kv::KeyView;
27use logforth_core::kv::ValueView;
28use logforth_core::kv::Visitor;
29use logforth_core::record::Record;
30
31/// An appender that adds log records to fastrace as an event associated to the current span.
32///
33/// # Examples
34///
35/// ```
36/// use logforth_append_fastrace::FastraceEvent;
37///
38/// let fastrace_appender = FastraceEvent::default();
39/// ```
40///
41/// # Caveats
42///
43/// The caller or application should ensure that the `flush` method or [`fastrace::flush`] is called
44/// before the program exits to collect the final events, especially when this appender is used
45/// in a global context.
46#[derive(Default, Debug, Clone)]
47#[non_exhaustive]
48pub struct FastraceEvent {}
49
50impl Append for FastraceEvent {
51    fn append(&self, record: &Record, diags: &[Box<dyn Diagnostic>]) -> Result<(), Error> {
52        let message = if let Some(msg) = record.payload_static() {
53            Cow::Borrowed(msg)
54        } else {
55            Cow::Owned(record.payload().to_string())
56        };
57
58        let mut collector = KvCollector { kv: Vec::new() };
59        record.key_values().visit(&mut collector)?;
60        for d in diags {
61            d.visit(&mut collector)?;
62        }
63
64        fastrace::local::LocalSpan::add_event(fastrace::Event::new(message).with_properties(
65            || {
66                [
67                    (Cow::from("level"), Cow::from(record.level().name())),
68                    (Cow::from("timestamp"), Cow::from(Zoned::now().to_string())),
69                ]
70                .into_iter()
71                .chain(collector.kv)
72            },
73        ));
74
75        Ok(())
76    }
77
78    fn flush(&self) -> Result<(), Error> {
79        fastrace::flush();
80        Ok(())
81    }
82}
83
84struct KvCollector {
85    kv: Vec<(Cow<'static, str>, Cow<'static, str>)>,
86}
87
88impl Visitor for KvCollector {
89    fn visit(&mut self, key: KeyView, value: ValueView) -> Result<(), Error> {
90        let k = key.to_cow();
91        let v = if let Some(s) = value.to_static_str() {
92            Cow::Borrowed(s)
93        } else {
94            Cow::Owned(value.to_string())
95        };
96        self.kv.push((k, v));
97        Ok(())
98    }
99}
logforth_append_fastrace/lib.rs

logforth_append_fastrace/
lib.rs
