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::Read;
16use std::io::Write as _;
17use std::path::Path;
18use std::path::PathBuf;
19use std::sync::Arc;
20use tracing::Level;
21use tracing::level_filters::LevelFilter;
22use tracing_subscriber::filter::Targets;
23use tracing_subscriber::fmt::MakeWriter;
24use tracing_subscriber::fmt::format::FmtSpan;
25use tracing_subscriber::layer::SubscriberExt;
26use tracing_subscriber::util::SubscriberInitExt;
27
28/// A source of [`PetriLogFile`] log files for test output.
29#[derive(Clone, Debug)]
30pub struct PetriLogSource(Arc<LogSourceInner>);
31
32#[derive(Debug)]
33struct LogSourceInner {
34    root_path: PathBuf,
35    json_log: JsonLog,
36    log_files: Mutex<HashMap<String, PetriLogFile>>,
37    attachments: Mutex<HashMap<String, u64>>,
38}
39
40impl PetriLogSource {
41    /// Returns a log file for the given name.
42    ///
43    /// The name should not have an extension; `.log` will be appended
44    /// automatically.
45    pub fn log_file(&self, name: &str) -> anyhow::Result<PetriLogFile> {
46        use std::collections::hash_map::Entry;
47
48        let mut log_files = self.0.log_files.lock();
49        let log_file = match log_files.entry(name.to_owned()) {
50            Entry::Occupied(occupied_entry) => occupied_entry.get().clone(),
51            Entry::Vacant(vacant_entry) => {
52                let mut path = self.0.root_path.join(name);
53                // Note that .log is preferred to .txt at least partially
54                // because WSL2 and Defender reportedly conspire to make
55                // cross-OS .txt file accesses extremely slow.
56                path.set_extension("log");
57                let file = File::create(&path)?;
58                // Write the path to the file in junit attachment syntax to
59                // stdout to ensure the file is attached to the test result.
60                println!("[[ATTACHMENT|{}]]", path.display());
61                vacant_entry
62                    .insert(PetriLogFile(Arc::new(LogFileInner {
63                        file,
64                        json_log: self.0.json_log.clone(),
65                        source: name.to_owned(),
66                    })))
67                    .clone()
68            }
69        };
70        Ok(log_file)
71    }
72
73    fn attachment_path(&self, name: &str) -> PathBuf {
74        let mut attachments = self.0.attachments.lock();
75        let next = attachments.entry(name.to_owned()).or_default();
76        let name = Path::new(name);
77        let name = if *next == 0 {
78            name
79        } else {
80            let base = name.file_stem().unwrap().to_str().unwrap();
81            let extension = name.extension().unwrap_or_default();
82            &Path::new(&format!("{}_{}", base, *next)).with_extension(extension)
83        };
84        *next += 1;
85        self.0.root_path.join(name)
86    }
87
88    /// Creates a file with the given name and returns a handle to it.
89    ///
90    /// If the file already exists, a unique name is generated by appending
91    /// a number to the base name.
92    pub fn create_attachment(&self, filename: &str) -> anyhow::Result<File> {
93        let path = self.attachment_path(filename);
94        let file = File::create(&path)?;
95        self.trace_attachment(&path);
96        Ok(file)
97    }
98
99    /// Writes the given data to a file with the given name.
100    ///
101    /// If the file already exists, a unique name is generated by appending
102    /// a number to the base name.
103    pub fn write_attachment(&self, filename: &str, mut data: impl Read) -> anyhow::Result<PathBuf> {
104        let path = self.attachment_path(filename);
105        let mut file = File::create(&path)?;
106        std::io::copy(&mut data, &mut file)?;
107        self.trace_attachment(&path);
108        Ok(path)
109    }
110
111    /// Copies the given file path to a file with the given name.
112    ///
113    /// If the file already exists, a unique name is generated by appending
114    /// a number to the base name.
115    pub fn copy_attachment(
116        &self,
117        attachment_filename: &str,
118        source_path: &Path,
119    ) -> anyhow::Result<()> {
120        let dest_path = self.attachment_path(attachment_filename);
121        fs_err::copy(source_path, &dest_path)?;
122        self.trace_attachment(&dest_path);
123        Ok(())
124    }
125
126    fn trace_attachment(&self, path: &Path) {
127        // Just write the relative path to the JSON log.
128        self.0
129            .json_log
130            .write_attachment(path.file_name().unwrap().as_ref());
131        println!("[[ATTACHMENT|{}]]", path.display());
132    }
133
134    /// Traces and logs the result of a test run in the format expected by our tooling.
135    pub fn log_test_result(&self, name: &str, r: &anyhow::Result<()>) {
136        let result_path = match &r {
137            Ok(()) => {
138                tracing::info!("test passed");
139                "petri.passed"
140            }
141            Err(err) => {
142                tracing::error!(
143                    error = err.as_ref() as &dyn std::error::Error,
144                    "test failed"
145                );
146                "petri.failed"
147            }
148        };
149        // Write a file to the output directory to indicate whether the test
150        // passed, for easy scanning via tools.
151        fs_err::write(self.0.root_path.join(result_path), name).unwrap();
152    }
153
154    /// Returns the output directory for log files.
155    pub fn output_dir(&self) -> &Path {
156        &self.0.root_path
157    }
158}
159
160#[derive(Clone, Debug)]
161struct JsonLog(Arc<File>);
162
163impl JsonLog {
164    fn write_json(&self, v: &impl serde::Serialize) {
165        let v = serde_json::to_vec(v);
166        if let Ok(mut v) = v {
167            v.push(b'\n');
168            // Write once to avoid interleaving JSON entries.
169            let _ = self.0.as_ref().write_all(&v);
170        }
171    }
172
173    fn write_entry(&self, timestamp: Option<Timestamp>, level: Level, source: &str, buf: &[u8]) {
174        #[derive(serde::Serialize)]
175        struct JsonEntry<'a> {
176            timestamp: Timestamp,
177            source: &'a str,
178            severity: &'a str,
179            message: &'a str,
180        }
181        let message = String::from_utf8_lossy(buf);
182        self.write_json(&JsonEntry {
183            timestamp: timestamp.unwrap_or_else(Timestamp::now),
184            source,
185            severity: level.as_str(),
186            message: message.trim_ascii(),
187        });
188    }
189
190    fn write_attachment(&self, path: &Path) {
191        #[derive(serde::Serialize)]
192        struct JsonEntry<'a> {
193            timestamp: Timestamp,
194            attachment: &'a Path,
195        }
196        self.write_json(&JsonEntry {
197            timestamp: Timestamp::now(),
198            attachment: path,
199        });
200    }
201}
202
203#[derive(Debug)]
204struct LogFileInner {
205    file: File,
206    json_log: JsonLog,
207    source: String,
208}
209
210impl LogFileInner {
211    fn write_stdout(&self, buf: &[u8]) {
212        let mut stdout = std::io::stdout().lock();
213        write!(stdout, "[{:>10}] ", self.source).unwrap();
214        stdout.write_all(buf).unwrap();
215    }
216}
217
218struct LogWriter<'a> {
219    inner: &'a LogFileInner,
220    level: Level,
221    timestamp: Option<Timestamp>,
222}
223
224impl std::io::Write for LogWriter<'_> {
225    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
226        // Write to the JSONL file.
227        self.inner
228            .json_log
229            .write_entry(self.timestamp, self.level, &self.inner.source, buf);
230        // Write to the specific log file.
231        let _ = (&self.inner.file).write_all(buf);
232        // Write to stdout, prefixed with the source.
233        self.inner.write_stdout(buf);
234        Ok(buf.len())
235    }
236
237    fn flush(&mut self) -> std::io::Result<()> {
238        Ok(())
239    }
240}
241
242/// A log file for writing test output.
243///
244/// Generally, you should use [`tracing`] for test-generated logging. This type
245/// is for writing fully-formed text entries that come from an external source,
246/// such as another process or a guest serial port.
247#[derive(Clone, Debug)]
248pub struct PetriLogFile(Arc<LogFileInner>);
249
250impl PetriLogFile {
251    /// Write a log entry with the given format arguments.
252    pub fn write_entry_fmt(
253        &self,
254        timestamp: Option<Timestamp>,
255        level: Level,
256        args: std::fmt::Arguments<'_>,
257    ) {
258        // Convert to a single string to write to the file to ensure the entry
259        // does not get interleaved with other log entries.
260        let _ = LogWriter {
261            inner: &self.0,
262            level,
263            timestamp,
264        }
265        .write_all(format!("{}\n", args).as_bytes());
266    }
267
268    /// Write a log entry with the given message.
269    pub fn write_entry(&self, message: impl std::fmt::Display) {
270        self.write_entry_fmt(None, Level::INFO, format_args!("{}", message));
271    }
272}
273
274/// Write a formatted log entry to the given [`PetriLogFile`].
275#[macro_export]
276macro_rules! log {
277    ($file:expr, $($arg:tt)*) => {
278        <$crate::PetriLogFile>::write_entry_fmt(&$file, format_args!($($arg)*))
279    };
280}
281
282/// Initialize Petri tracing with the given output path for log files.
283///
284/// Events go to three places:
285/// - `petri.jsonl`, in newline-separated JSON format.
286/// - standard output, in human readable format.
287/// - a log file, in human readable format. This file is `petri.log`, except
288///   for events whose target ends in `.log`, which go to separate files named by
289///   the target.
290pub fn try_init_tracing(root_path: &Path) -> anyhow::Result<PetriLogSource> {
291    let targets =
292        if let Ok(var) = std::env::var("OPENVMM_LOG").or_else(|_| std::env::var("HVLITE_LOG")) {
293            var.parse().unwrap()
294        } else {
295            Targets::new().with_default(LevelFilter::DEBUG)
296        };
297
298    // Canonicalize so that printed attachment paths are most likely to work.
299    let root_path = root_path.fs_err_canonicalize()?;
300    let jsonl = File::create(root_path.join("petri.jsonl"))?;
301    let logger = PetriLogSource(Arc::new(LogSourceInner {
302        json_log: JsonLog(Arc::new(jsonl)),
303        root_path,
304        log_files: Default::default(),
305        attachments: Default::default(),
306    }));
307
308    let petri_log = logger.log_file("petri")?;
309
310    tracing_subscriber::fmt()
311        .compact()
312        .with_ansi(false) // avoid polluting logs with escape sequences
313        .log_internal_errors(true)
314        .with_writer(PetriWriter(petri_log))
315        .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
316        .with_max_level(LevelFilter::TRACE)
317        .finish()
318        .with(targets)
319        .try_init()?;
320
321    Ok(logger)
322}
323
324struct PetriWriter(PetriLogFile);
325
326impl<'a> MakeWriter<'a> for PetriWriter {
327    type Writer = LogWriter<'a>;
328
329    fn make_writer(&'a self) -> Self::Writer {
330        LogWriter {
331            inner: &self.0.0,
332            level: Level::INFO,
333            timestamp: None,
334        }
335    }
336
337    fn make_writer_for(&'a self, meta: &tracing::Metadata<'_>) -> Self::Writer {
338        LogWriter {
339            inner: &self.0.0,
340            level: *meta.level(),
341            timestamp: None,
342        }
343    }
344}
345
346/// Logs lines from `reader` into `log_file`.
347///
348/// Attempts to parse lines as `SyslogParsedEntry`, extracting the log level.
349/// Passes through any non-conforming logs.
350pub async fn log_task(
351    log_file: PetriLogFile,
352    reader: impl AsyncRead + Unpin + Send + 'static,
353    name: &str,
354) -> anyhow::Result<()> {
355    tracing::info!("connected to {name}");
356    let mut buf = Vec::new();
357    let mut reader = BufReader::new(reader);
358    loop {
359        buf.clear();
360        match (&mut reader).take(256).read_until(b'\n', &mut buf).await {
361            Ok(0) => {
362                tracing::info!("disconnected from {name}: EOF");
363                return Ok(());
364            }
365            Err(e) => {
366                tracing::info!("disconnected from {name}: error: {e:#}");
367                return Err(e.into());
368            }
369            _ => {}
370        }
371
372        let string_buf = String::from_utf8_lossy(&buf);
373        let string_buf_trimmed = string_buf.trim_end();
374
375        if let Some(message) = kmsg::SyslogParsedEntry::new(string_buf_trimmed) {
376            let level = kernel_level_to_tracing_level(message.level);
377            log_file.write_entry_fmt(None, level, format_args!("{}", message.display(false)));
378        } else {
379            log_file.write_entry(string_buf_trimmed);
380        }
381    }
382}
383
384/// Maps kernel log levels to tracing levels.
385fn kernel_level_to_tracing_level(kernel_level: u8) -> Level {
386    match kernel_level {
387        0..=3 => Level::ERROR,
388        4 => Level::WARN,
389        5..=6 => Level::INFO,
390        7 => Level::DEBUG,
391        _ => Level::INFO,
392    }
393}
394
395/// read from the kmsg stream and write entries to the log
396pub async fn kmsg_log_task(
397    log_file: PetriLogFile,
398    diag_client: diag_client::DiagClient,
399) -> anyhow::Result<()> {
400    loop {
401        diag_client.wait_for_server().await?;
402        let mut kmsg = diag_client.kmsg(true).await?;
403        tracing::info!("kmsg connected");
404        while let Some(data) = kmsg.next().await {
405            match data {
406                Ok(data) => {
407                    let message = KmsgParsedEntry::new(&data).unwrap();
408                    let level = kernel_level_to_tracing_level(message.level);
409                    log_file.write_entry_fmt(
410                        None,
411                        level,
412                        format_args!("{}", message.display(false)),
413                    );
414                }
415                Err(err) => {
416                    tracing::info!("kmsg disconnected: {err:#}");
417                    break;
418                }
419            }
420        }
421    }
422}
423
424#[cfg(test)]
425mod tests {
426    use super::*;
427
428    #[test]
429    fn test_kernel_level_to_tracing_level() {
430        // Test emergency to error levels (0-3)
431        assert_eq!(kernel_level_to_tracing_level(0), Level::ERROR);
432        assert_eq!(kernel_level_to_tracing_level(1), Level::ERROR);
433        assert_eq!(kernel_level_to_tracing_level(2), Level::ERROR);
434        assert_eq!(kernel_level_to_tracing_level(3), Level::ERROR);
435
436        // Test warning level (4)
437        assert_eq!(kernel_level_to_tracing_level(4), Level::WARN);
438
439        // Test notice and info levels (5-6)
440        assert_eq!(kernel_level_to_tracing_level(5), Level::INFO);
441        assert_eq!(kernel_level_to_tracing_level(6), Level::INFO);
442
443        // Test debug level (7)
444        assert_eq!(kernel_level_to_tracing_level(7), Level::DEBUG);
445
446        // Test unknown level (fallback)
447        assert_eq!(kernel_level_to_tracing_level(8), Level::INFO);
448        assert_eq!(kernel_level_to_tracing_level(255), Level::INFO);
449    }
450}
petri/tracing.rs

petri/
tracing.rs
