petri/
tracing.rs

1// Copyright (c) Microsoft Corporation.
2// Licensed under the MIT License.
3
4use fs_err::File;
5use fs_err::PathExt;
6use futures::AsyncBufReadExt;
7use futures::AsyncRead;
8use futures::AsyncReadExt;
9use futures::StreamExt;
10use futures::io::BufReader;
11use jiff::Timestamp;
12use kmsg::KmsgParsedEntry;
13use parking_lot::Mutex;
14use std::collections::HashMap;
15use std::io::Write as _;
16use std::path::Path;
17use std::path::PathBuf;
18use std::sync::Arc;
19use tracing::Level;
20use tracing::level_filters::LevelFilter;
21use tracing_subscriber::filter::Targets;
22use tracing_subscriber::fmt::MakeWriter;
23use tracing_subscriber::fmt::format::FmtSpan;
24use tracing_subscriber::layer::SubscriberExt;
25use tracing_subscriber::util::SubscriberInitExt;
26
27/// A source of [`PetriLogFile`] log files for test output.
28#[derive(Clone)]
29pub struct PetriLogSource(Arc<LogSourceInner>);
30
31struct LogSourceInner {
32    root_path: PathBuf,
33    json_log: JsonLog,
34    log_files: Mutex<HashMap<String, PetriLogFile>>,
35    attachments: Mutex<HashMap<String, u64>>,
36}
37
38impl PetriLogSource {
39    /// Returns a log file for the given name.
40    ///
41    /// The name should not have an extension; `.log` will be appended
42    /// automatically.
43    pub fn log_file(&self, name: &str) -> anyhow::Result<PetriLogFile> {
44        use std::collections::hash_map::Entry;
45
46        let mut log_files = self.0.log_files.lock();
47        let log_file = match log_files.entry(name.to_owned()) {
48            Entry::Occupied(occupied_entry) => occupied_entry.get().clone(),
49            Entry::Vacant(vacant_entry) => {
50                let mut path = self.0.root_path.join(name);
51                // Note that .log is preferred to .txt at least partially
52                // because WSL2 and Defender reportedly conspire to make
53                // cross-OS .txt file accesses extremely slow.
54                path.set_extension("log");
55                let file = File::create(&path)?;
56                // Write the path to the file in junit attachment syntax to
57                // stdout to ensure the file is attached to the test result.
58                println!("[[ATTACHMENT|{}]]", path.display());
59                vacant_entry
60                    .insert(PetriLogFile(Arc::new(LogFileInner {
61                        file,
62                        json_log: self.0.json_log.clone(),
63                        source: name.to_owned(),
64                    })))
65                    .clone()
66            }
67        };
68        Ok(log_file)
69    }
70
71    fn attachment_path(&self, name: &str) -> PathBuf {
72        let mut attachments = self.0.attachments.lock();
73        let next = attachments.entry(name.to_owned()).or_default();
74        let name = Path::new(name);
75        let name = if *next == 0 {
76            name
77        } else {
78            let base = name.file_stem().unwrap().to_str().unwrap();
79            let extension = name.extension().unwrap_or_default();
80            &Path::new(&format!("{}_{}", base, *next)).with_extension(extension)
81        };
82        *next += 1;
83        self.0.root_path.join(name)
84    }
85
86    /// Creates a file with the given name and returns a handle to it.
87    ///
88    /// If the file already exists, a unique name is generated by appending
89    /// a number to the base name.
90    pub fn create_attachment(&self, filename: &str) -> anyhow::Result<File> {
91        let path = self.attachment_path(filename);
92        let file = File::create(&path)?;
93        self.trace_attachment(&path);
94        Ok(file)
95    }
96
97    /// Writes the given data to a file with the given name.
98    ///
99    /// If the file already exists, a unique name is generated by appending
100    /// a number to the base name.
101    pub fn write_attachment(
102        &self,
103        filename: &str,
104        data: impl AsRef<[u8]>,
105    ) -> anyhow::Result<PathBuf> {
106        let path = self.attachment_path(filename);
107        fs_err::write(&path, data)?;
108        self.trace_attachment(&path);
109        Ok(path)
110    }
111
112    fn trace_attachment(&self, path: &Path) {
113        // Just write the relative path to the JSON log.
114        self.0
115            .json_log
116            .write_attachment(path.file_name().unwrap().as_ref());
117        println!("[[ATTACHMENT|{}]]", path.display());
118    }
119}
120
121#[derive(Clone)]
122struct JsonLog(Arc<File>);
123
124impl JsonLog {
125    fn write_json(&self, v: &impl serde::Serialize) {
126        let v = serde_json::to_vec(v);
127        if let Ok(mut v) = v {
128            v.push(b'\n');
129            // Write once to avoid interleaving JSON entries.
130            let _ = self.0.as_ref().write_all(&v);
131        }
132    }
133
134    fn write_entry(&self, timestamp: Option<Timestamp>, level: Level, source: &str, buf: &[u8]) {
135        #[derive(serde::Serialize)]
136        struct JsonEntry<'a> {
137            timestamp: Timestamp,
138            source: &'a str,
139            severity: &'a str,
140            message: &'a str,
141        }
142        let message = String::from_utf8_lossy(buf);
143        self.write_json(&JsonEntry {
144            timestamp: timestamp.unwrap_or_else(Timestamp::now),
145            source,
146            severity: level.as_str(),
147            message: message.trim_ascii(),
148        });
149    }
150
151    fn write_attachment(&self, path: &Path) {
152        #[derive(serde::Serialize)]
153        struct JsonEntry<'a> {
154            timestamp: Timestamp,
155            attachment: &'a Path,
156        }
157        self.write_json(&JsonEntry {
158            timestamp: Timestamp::now(),
159            attachment: path,
160        });
161    }
162}
163
164struct LogFileInner {
165    file: File,
166    json_log: JsonLog,
167    source: String,
168}
169
170impl LogFileInner {
171    fn write_stdout(&self, buf: &[u8]) {
172        let mut stdout = std::io::stdout().lock();
173        write!(stdout, "[{:>10}] ", self.source).unwrap();
174        stdout.write_all(buf).unwrap();
175    }
176}
177
178struct LogWriter<'a> {
179    inner: &'a LogFileInner,
180    level: Level,
181    timestamp: Option<Timestamp>,
182}
183
184impl std::io::Write for LogWriter<'_> {
185    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
186        // Write to the JSONL file.
187        self.inner
188            .json_log
189            .write_entry(self.timestamp, self.level, &self.inner.source, buf);
190        // Write to the specific log file.
191        let _ = (&self.inner.file).write_all(buf);
192        // Write to stdout, prefixed with the source.
193        self.inner.write_stdout(buf);
194        Ok(buf.len())
195    }
196
197    fn flush(&mut self) -> std::io::Result<()> {
198        Ok(())
199    }
200}
201
202/// A log file for writing test output.
203///
204/// Generally, you should use [`tracing`] for test-generated logging. This type
205/// is for writing fully-formed text entries that come from an external source,
206/// such as another process or a guest serial port.
207#[derive(Clone)]
208pub struct PetriLogFile(Arc<LogFileInner>);
209
210impl PetriLogFile {
211    /// Write a log entry with the given format arguments.
212    pub fn write_entry_fmt(
213        &self,
214        timestamp: Option<Timestamp>,
215        level: Level,
216        args: std::fmt::Arguments<'_>,
217    ) {
218        // Convert to a single string to write to the file to ensure the entry
219        // does not get interleaved with other log entries.
220        let _ = LogWriter {
221            inner: &self.0,
222            level,
223            timestamp,
224        }
225        .write_all(format!("{}\n", args).as_bytes());
226    }
227
228    /// Write a log entry with the given message.
229    pub fn write_entry(&self, message: impl std::fmt::Display) {
230        self.write_entry_fmt(None, Level::INFO, format_args!("{}", message));
231    }
232}
233
234/// Write a formatted log entry to the given [`PetriLogFile`].
235#[macro_export]
236macro_rules! log {
237    ($file:expr, $($arg:tt)*) => {
238        <$crate::PetriLogFile>::write_entry_fmt(&$file, format_args!($($arg)*))
239    };
240}
241
242/// Initialize Petri tracing with the given output path for log files.
243///
244/// Events go to three places:
245/// - `petri.jsonl`, in newline-separated JSON format.
246/// - standard output, in human readable format.
247/// - a log file, in human readable format. This file is `petri.log`, except
248///   for events whose target ends in `.log`, which go to separate files named by
249///   the target.
250pub fn try_init_tracing(root_path: &Path) -> anyhow::Result<PetriLogSource> {
251    let targets =
252        if let Ok(var) = std::env::var("OPENVMM_LOG").or_else(|_| std::env::var("HVLITE_LOG")) {
253            var.parse().unwrap()
254        } else {
255            Targets::new().with_default(LevelFilter::DEBUG)
256        };
257
258    // Canonicalize so that printed attachment paths are most likely to work.
259    let root_path = root_path.fs_err_canonicalize()?;
260    let jsonl = File::create(root_path.join("petri.jsonl"))?;
261    let logger = PetriLogSource(Arc::new(LogSourceInner {
262        json_log: JsonLog(Arc::new(jsonl)),
263        root_path,
264        log_files: Default::default(),
265        attachments: Default::default(),
266    }));
267
268    let petri_log = logger.log_file("petri")?;
269
270    tracing_subscriber::fmt()
271        .compact()
272        .with_ansi(false) // avoid polluting logs with escape sequences
273        .log_internal_errors(true)
274        .with_writer(PetriWriter(petri_log))
275        .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
276        .with_max_level(LevelFilter::TRACE)
277        .finish()
278        .with(targets)
279        .try_init()?;
280
281    Ok(logger)
282}
283
284struct PetriWriter(PetriLogFile);
285
286impl<'a> MakeWriter<'a> for PetriWriter {
287    type Writer = LogWriter<'a>;
288
289    fn make_writer(&'a self) -> Self::Writer {
290        LogWriter {
291            inner: &self.0.0,
292            level: Level::INFO,
293            timestamp: None,
294        }
295    }
296
297    fn make_writer_for(&'a self, meta: &tracing::Metadata<'_>) -> Self::Writer {
298        LogWriter {
299            inner: &self.0.0,
300            level: *meta.level(),
301            timestamp: None,
302        }
303    }
304}
305
306/// Logs lines from `reader` into `log_file`.
307///
308/// Attempts to parse lines as `SyslogParsedEntry`, extracting the log level.
309/// Passes through any non-conforming logs.
310pub async fn log_task(
311    log_file: PetriLogFile,
312    reader: impl AsyncRead + Unpin + Send + 'static,
313    name: &str,
314) -> anyhow::Result<()> {
315    tracing::info!("connected to {name}");
316    let mut buf = Vec::new();
317    let mut reader = BufReader::new(reader);
318    loop {
319        buf.clear();
320        match (&mut reader).take(256).read_until(b'\n', &mut buf).await {
321            Ok(0) => {
322                tracing::info!("disconnected from {name}: EOF");
323                return Ok(());
324            }
325            Err(e) => {
326                tracing::info!("disconnected from {name}: error: {e:#}");
327                return Err(e.into());
328            }
329            _ => {}
330        }
331
332        let string_buf = String::from_utf8_lossy(&buf);
333        let string_buf_trimmed = string_buf.trim_end();
334
335        if let Some(message) = kmsg::SyslogParsedEntry::new(string_buf_trimmed) {
336            let level = kernel_level_to_tracing_level(message.level);
337            log_file.write_entry_fmt(None, level, format_args!("{}", message.display(false)));
338        } else {
339            log_file.write_entry(string_buf_trimmed);
340        }
341    }
342}
343
344/// Maps kernel log levels to tracing levels.
345fn kernel_level_to_tracing_level(kernel_level: u8) -> Level {
346    match kernel_level {
347        0..=3 => Level::ERROR,
348        4 => Level::WARN,
349        5..=6 => Level::INFO,
350        7 => Level::DEBUG,
351        _ => Level::INFO,
352    }
353}
354
355/// read from the kmsg stream and write entries to the log
356pub async fn kmsg_log_task(
357    log_file: PetriLogFile,
358    diag_client: diag_client::DiagClient,
359) -> anyhow::Result<()> {
360    loop {
361        diag_client.wait_for_server().await?;
362        let mut kmsg = diag_client.kmsg(true).await?;
363        tracing::info!("kmsg connected");
364        while let Some(data) = kmsg.next().await {
365            match data {
366                Ok(data) => {
367                    let message = KmsgParsedEntry::new(&data).unwrap();
368                    let level = kernel_level_to_tracing_level(message.level);
369                    log_file.write_entry_fmt(
370                        None,
371                        level,
372                        format_args!("{}", message.display(false)),
373                    );
374                }
375                Err(err) => {
376                    tracing::info!("kmsg disconnected: {err:#}");
377                    break;
378                }
379            }
380        }
381    }
382}
383
384#[cfg(test)]
385mod tests {
386    use super::*;
387
388    #[test]
389    fn test_kernel_level_to_tracing_level() {
390        // Test emergency to error levels (0-3)
391        assert_eq!(kernel_level_to_tracing_level(0), Level::ERROR);
392        assert_eq!(kernel_level_to_tracing_level(1), Level::ERROR);
393        assert_eq!(kernel_level_to_tracing_level(2), Level::ERROR);
394        assert_eq!(kernel_level_to_tracing_level(3), Level::ERROR);
395
396        // Test warning level (4)
397        assert_eq!(kernel_level_to_tracing_level(4), Level::WARN);
398
399        // Test notice and info levels (5-6)
400        assert_eq!(kernel_level_to_tracing_level(5), Level::INFO);
401        assert_eq!(kernel_level_to_tracing_level(6), Level::INFO);
402
403        // Test debug level (7)
404        assert_eq!(kernel_level_to_tracing_level(7), Level::DEBUG);
405
406        // Test unknown level (fallback)
407        assert_eq!(kernel_level_to_tracing_level(8), Level::INFO);
408        assert_eq!(kernel_level_to_tracing_level(255), Level::INFO);
409    }
410}
petri/tracing.rs

petri/
tracing.rs
