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ic_testkit/pic/
diagnostics.rs

1use std::{
2    fmt, io,
3    time::{Duration, Instant},
4};
5
6use ic_host_artifacts::batch::{BatchLabelError, validate_labels};
7use ic_platform::pocket_ic::{CanisterLogRecord, CanisterStatusResult, PocketIc};
8use ic_platform::principal::ExternalPrincipal as Principal;
9
10use super::{
11    PocketIcCallFailure,
12    transport::{self, capture_call},
13};
14
15/// Default maximum number of canister-log records retained in diagnostics.
16pub const DEFAULT_CANISTER_LOG_RECORD_LIMIT: usize = 32;
17
18/// Default maximum aggregate raw canister-log bytes retained in diagnostics.
19pub const DEFAULT_CANISTER_LOG_BYTE_LIMIT: usize = 16 * 1024;
20
21/// Explicit bounds applied when canister logs are converted to diagnostic text.
22#[derive(Clone, Copy, Debug, Eq, PartialEq)]
23pub struct CanisterLogRenderLimits {
24    /// Maximum retained records; zero retains none.
25    pub record_limit: usize,
26    /// Maximum retained raw-content bytes; zero retains none.
27    pub byte_limit: usize,
28}
29
30impl Default for CanisterLogRenderLimits {
31    fn default() -> Self {
32        Self {
33            record_limit: DEFAULT_CANISTER_LOG_RECORD_LIMIT,
34            byte_limit: DEFAULT_CANISTER_LOG_BYTE_LIMIT,
35        }
36    }
37}
38
39/// Exact controller-aware inputs for one best-effort diagnostic collection.
40#[derive(Clone, Copy, Debug, Eq, PartialEq)]
41pub struct CanisterDiagnosticsRequest {
42    /// Canister to inspect.
43    pub canister_id: Principal,
44    /// Exact sender for the status request.
45    pub status_sender: Principal,
46    /// Exact sender for the log request.
47    pub log_sender: Principal,
48    /// Caller-selected log rendering bounds.
49    pub log_limits: CanisterLogRenderLimits,
50}
51
52/// One caller-labeled exact diagnostic request in a collect-all batch.
53#[derive(Clone, Debug, Eq, PartialEq)]
54pub struct LabeledCanisterDiagnosticsRequest {
55    /// Caller label, checked for emptiness and uniqueness before collection.
56    pub label: String,
57    /// Exact controller-aware diagnostic inputs.
58    pub request: CanisterDiagnosticsRequest,
59}
60
61/// One canister-log record retained as bounded lossy UTF-8 text.
62#[derive(Clone, Debug, Eq, PartialEq)]
63pub struct CanisterDiagnosticLogRecord {
64    index: u64,
65    timestamp_nanos: u64,
66    content: String,
67    original_content_bytes: usize,
68    omitted_content_bytes: usize,
69}
70
71impl CanisterDiagnosticLogRecord {
72    /// Upstream record index.
73    #[must_use]
74    pub const fn index(&self) -> u64 {
75        self.index
76    }
77
78    /// Upstream record timestamp in nanoseconds.
79    #[must_use]
80    pub const fn timestamp_nanos(&self) -> u64 {
81        self.timestamp_nanos
82    }
83
84    /// Retained content converted with lossy UTF-8 decoding.
85    #[must_use]
86    pub fn content(&self) -> &str {
87        &self.content
88    }
89
90    /// Original raw content length before bounding and conversion.
91    #[must_use]
92    pub const fn original_content_bytes(&self) -> usize {
93        self.original_content_bytes
94    }
95
96    /// Raw content bytes omitted from this retained record.
97    #[must_use]
98    pub const fn omitted_content_bytes(&self) -> usize {
99        self.omitted_content_bytes
100    }
101
102    /// Whether this record's content was truncated.
103    #[must_use]
104    pub const fn was_truncated(&self) -> bool {
105        self.omitted_content_bytes != 0
106    }
107}
108
109/// Successfully fetched canister logs after bounded text conversion.
110#[derive(Clone, Debug, Eq, PartialEq)]
111pub struct CanisterDiagnosticLogs {
112    records: Vec<CanisterDiagnosticLogRecord>,
113    total_records: usize,
114    total_content_bytes: usize,
115    omitted_content_bytes: usize,
116}
117
118impl CanisterDiagnosticLogs {
119    /// Retained records in upstream order.
120    #[must_use]
121    pub fn records(&self) -> &[CanisterDiagnosticLogRecord] {
122        &self.records
123    }
124
125    /// Total number of records returned by `PocketIC` before bounding.
126    #[must_use]
127    pub const fn total_records(&self) -> usize {
128        self.total_records
129    }
130
131    /// Total raw content bytes returned by `PocketIC` before bounding.
132    #[must_use]
133    pub const fn total_content_bytes(&self) -> usize {
134        self.total_content_bytes
135    }
136
137    /// Number of whole records omitted by the configured bounds.
138    #[must_use]
139    pub const fn omitted_records(&self) -> usize {
140        self.total_records - self.records.len()
141    }
142
143    /// Aggregate raw content bytes omitted across retained and omitted records.
144    #[must_use]
145    pub const fn omitted_content_bytes(&self) -> usize {
146        self.omitted_content_bytes
147    }
148
149    /// Whether either whole records or record content were truncated.
150    #[must_use]
151    pub const fn was_truncated(&self) -> bool {
152        self.omitted_records() != 0 || self.omitted_content_bytes != 0
153    }
154}
155
156impl fmt::Display for CanisterDiagnosticLogs {
157    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
158        if self.records.is_empty() {
159            if self.total_records == 0 {
160                formatter.write_str("<empty>")?;
161            } else {
162                formatter.write_str("<no retained records>")?;
163            }
164        } else {
165            for (position, record) in self.records.iter().enumerate() {
166                if position != 0 {
167                    formatter.write_str(", ")?;
168                }
169                write!(
170                    formatter,
171                    "[{}@{}]={:?}",
172                    record.index, record.timestamp_nanos, record.content
173                )?;
174                if record.was_truncated() {
175                    write!(
176                        formatter,
177                        " (truncated {} bytes)",
178                        record.omitted_content_bytes
179                    )?;
180                }
181            }
182        }
183        if self.was_truncated() {
184            write!(
185                formatter,
186                "; truncated omitted_records={} omitted_content_bytes={}",
187                self.omitted_records(),
188                self.omitted_content_bytes
189            )?;
190        }
191        Ok(())
192    }
193}
194
195/// Independent status and log outcomes for one diagnostic collection.
196#[derive(Debug)]
197pub struct CanisterDiagnosticsReport {
198    /// Exact request used for this report.
199    pub request: CanisterDiagnosticsRequest,
200    /// Status result, independent of log retrieval.
201    pub status: Result<CanisterStatusResult, PocketIcCallFailure>,
202    /// Log result, independent of status retrieval.
203    pub logs: Result<CanisterDiagnosticLogs, PocketIcCallFailure>,
204}
205
206impl CanisterDiagnosticsReport {
207    /// Whether both status and log collection succeeded.
208    #[must_use]
209    pub const fn is_success(&self) -> bool {
210        self.status.is_ok() && self.logs.is_ok()
211    }
212}
213
214/// One ordered labeled entry in a collect-all diagnostics batch.
215#[derive(Debug)]
216pub struct CanisterDiagnosticsBatchEntry {
217    /// Caller-supplied label.
218    pub label: String,
219    /// Structured status and log outcomes for this entry.
220    pub report: CanisterDiagnosticsReport,
221    /// Complete wall-clock time for this target's diagnostic collection.
222    pub entry_elapsed: Duration,
223}
224
225impl CanisterDiagnosticsBatchEntry {
226    /// Whether both status and log collection succeeded for this entry.
227    #[must_use]
228    pub const fn is_success(&self) -> bool {
229        self.report.is_success()
230    }
231}
232
233/// Ordered entries from a sequential collect-all diagnostics batch.
234#[derive(Debug, Default)]
235pub struct CanisterDiagnosticsBatchReport {
236    /// Entries in the supplied request order.
237    pub entries: Vec<CanisterDiagnosticsBatchEntry>,
238    /// Complete wall-clock time for the sequential collect-all batch.
239    pub total: Duration,
240}
241
242impl CanisterDiagnosticsBatchReport {
243    /// Entries with at least one failed status or log operation.
244    pub fn failures(&self) -> impl Iterator<Item = &CanisterDiagnosticsBatchEntry> {
245        self.entries.iter().filter(|entry| !entry.is_success())
246    }
247
248    /// Whether every entry collected both status and logs successfully.
249    #[must_use]
250    pub fn is_success(&self) -> bool {
251        self.entries
252            .iter()
253            .all(CanisterDiagnosticsBatchEntry::is_success)
254    }
255}
256
257impl fmt::Display for CanisterDiagnosticsBatchReport {
258    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
259        write!(
260            formatter,
261            "diagnostics={} total={:?}",
262            self.entries.len(),
263            self.total
264        )?;
265        for entry in &self.entries {
266            write!(
267                formatter,
268                "; label={:?} elapsed={:?} {}",
269                entry.label, entry.entry_elapsed, entry.report
270            )?;
271        }
272        Ok(())
273    }
274}
275
276impl fmt::Display for CanisterDiagnosticsReport {
277    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
278        write!(
279            formatter,
280            "canister={} status_sender={} status=",
281            self.request.canister_id, self.request.status_sender
282        )?;
283        match &self.status {
284            Ok(status) => write!(
285                formatter,
286                "ok(state={:?} version={} controllers={} module_hash_bytes={} memory_bytes={} cycles={})",
287                status.status,
288                status.version,
289                status.settings.controllers.len(),
290                status.module_hash.as_ref().map_or(0, Vec::len),
291                status.memory_size,
292                status.cycles,
293            ),
294            Err(failure) => write!(formatter, "<{failure}>"),
295        }?;
296        write!(formatter, " log_sender={} logs=", self.request.log_sender)?;
297        match &self.logs {
298            Err(failure) => write!(formatter, "<{failure}>")?,
299            Ok(logs) => write!(formatter, "{logs}")?,
300        }
301        Ok(())
302    }
303}
304
305/// Reusable structured `PocketIC` failure diagnostics.
306pub trait PocketIcDiagnosticsExt {
307    /// Collect status and bounded logs using the request's exact senders.
308    ///
309    /// Both calls are attempted independently. `PocketIC` transport panics are
310    /// captured so diagnostics can remain subordinate to the original failure.
311    fn collect_canister_diagnostics(
312        &self,
313        request: CanisterDiagnosticsRequest,
314    ) -> CanisterDiagnosticsReport;
315
316    /// Explicitly collect and write one contextual diagnostic report.
317    ///
318    /// Uses the request's exact senders and log limits, with no retry or output
319    /// destination selected implicitly. Collection, formatting and writer panics
320    /// are captured as an IO error retaining [`super::PocketIcOperationError`].
321    /// Ordinary writer errors are returned unchanged. Status/log failures remain
322    /// in the written report; successful output does not mean those calls passed.
323    /// Callers keep their primary failure authoritative and decide whether to
324    /// retain or ignore this secondary reporting result.
325    ///
326    /// # Errors
327    /// Returns the writer’s I/O error when diagnostics cannot be written.
328    fn write_canister_diagnostics(
329        &self,
330        request: CanisterDiagnosticsRequest,
331        context: &str,
332        writer: &mut dyn io::Write,
333    ) -> io::Result<()> {
334        transport::capture_operation(|| {
335            let report = self.collect_canister_diagnostics(request);
336            writeln!(writer, "{context}: {report}")
337        })
338        .map_err(io::Error::other)?
339    }
340
341    /// Collect every labeled request sequentially in its supplied order.
342    ///
343    /// Every target is attempted even when an earlier entry fails or panics.
344    /// Each entry preserves its exact request and independent status/log
345    /// outcomes; no anonymous retry or fallback is performed.
346    /// Invalid labels return Host's [`BatchLabelError`] before collection starts.
347    ///
348    /// # Errors
349    /// Rejects invalid or duplicate labels before collecting diagnostics.
350    fn collect_canister_diagnostics_batch(
351        &self,
352        requests: &[LabeledCanisterDiagnosticsRequest],
353    ) -> Result<CanisterDiagnosticsBatchReport, BatchLabelError> {
354        validate_labels(requests.iter().map(|request| request.label.as_str()))?;
355        let started = Instant::now();
356        let entries = requests
357            .iter()
358            .map(|labeled| {
359                let entry_started = Instant::now();
360                let request = labeled.request;
361                let report =
362                    transport::capture_operation(|| self.collect_canister_diagnostics(request))
363                        .unwrap_or_else(|source| CanisterDiagnosticsReport {
364                            request,
365                            status: Err(PocketIcCallFailure::Operation(source.clone())),
366                            logs: Err(PocketIcCallFailure::Operation(source)),
367                        });
368                CanisterDiagnosticsBatchEntry {
369                    label: labeled.label.clone(),
370                    report,
371                    entry_elapsed: entry_started.elapsed(),
372                }
373            })
374            .collect();
375        Ok(CanisterDiagnosticsBatchReport {
376            entries,
377            total: started.elapsed(),
378        })
379    }
380}
381
382impl PocketIcDiagnosticsExt for PocketIc {
383    fn collect_canister_diagnostics(
384        &self,
385        request: CanisterDiagnosticsRequest,
386    ) -> CanisterDiagnosticsReport {
387        let status =
388            capture_call(|| self.canister_status(request.canister_id, Some(request.status_sender)));
389        let logs =
390            capture_call(|| self.fetch_canister_logs(request.canister_id, request.log_sender))
391                .map(|records| render_log_records(records, request.log_limits));
392
393        CanisterDiagnosticsReport {
394            request,
395            status,
396            logs,
397        }
398    }
399}
400
401fn render_log_records(
402    records: Vec<CanisterLogRecord>,
403    limits: CanisterLogRenderLimits,
404) -> CanisterDiagnosticLogs {
405    let total_records = records.len();
406    let mut total_content_bytes = 0usize;
407    let mut rendered = Vec::with_capacity(total_records.min(limits.record_limit));
408    let mut retained_bytes = 0usize;
409    let mut omitted_content_bytes = 0usize;
410
411    for record in records {
412        total_content_bytes = total_content_bytes.saturating_add(record.content.len());
413        if rendered.len() == limits.record_limit || retained_bytes == limits.byte_limit {
414            omitted_content_bytes = omitted_content_bytes.saturating_add(record.content.len());
415            continue;
416        }
417
418        let available = limits.byte_limit.saturating_sub(retained_bytes);
419        let retained = record.content.len().min(available);
420        let omitted = record.content.len().saturating_sub(retained);
421        let content = String::from_utf8_lossy(&record.content[..retained]).into_owned();
422        retained_bytes = retained_bytes.saturating_add(retained);
423        omitted_content_bytes = omitted_content_bytes.saturating_add(omitted);
424        rendered.push(CanisterDiagnosticLogRecord {
425            index: record.idx,
426            timestamp_nanos: record.timestamp_nanos,
427            content,
428            original_content_bytes: record.content.len(),
429            omitted_content_bytes: omitted,
430        });
431    }
432
433    CanisterDiagnosticLogs {
434        records: rendered,
435        total_records,
436        total_content_bytes,
437        omitted_content_bytes,
438    }
439}
440
441#[cfg(test)]
442mod tests {
443    use std::cell::Cell;
444
445    use ic_host_artifacts::batch::BatchLabelError;
446    use ic_platform::pocket_ic::CanisterLogRecord;
447    use ic_platform::principal::ExternalPrincipal as Principal;
448
449    use super::{
450        CanisterDiagnosticsReport, CanisterDiagnosticsRequest, CanisterLogRenderLimits,
451        LabeledCanisterDiagnosticsRequest, PocketIcCallFailure, PocketIcDiagnosticsExt,
452        capture_call, render_log_records,
453    };
454
455    #[test]
456    fn diagnostic_transport_classification_survives_context_and_io_wrapping() {
457        const REFUSED: &str = "HTTP failure: reqwest::Error { kind: Request, url: \"http://127.0.0.1:1234/instances/0/read/get_time\", source: ConnectError(\"tcp connect error\", Os { code: 111, kind: ConnectionRefused, message: \"Connection refused\" }) }";
458        const RESET: &str = "HTTP failure: reqwest::Error { kind: Request, url: \"http://127.0.0.1:49238/instances/0/read/get_time\", source: hyper_util::client::legacy::Error(SendRequest, hyper::Error(Io, Os { code: 54, kind: ConnectionReset, message: \"Connection reset by peer\" })) }";
459        for message in [REFUSED, RESET, "application worker channel closed"] {
460            let error = capture_call::<()>(|| panic!("{message}"))
461                .expect_err("diagnostic operation should capture the panic");
462            let expected = message != "application worker channel closed";
463            let PocketIcCallFailure::Operation(source) = &error else {
464                panic!("expected the original operation error");
465            };
466            assert_eq!(source.message(), message);
467            assert_eq!(source.is_transport(), expected);
468            let chained = std::error::Error::source(&error)
469                .and_then(|cause| cause.downcast_ref::<super::super::PocketIcOperationError>())
470                .expect("diagnostic error exposes its original typed cause");
471            assert_eq!(chained, source);
472            assert_eq!(
473                super::super::is_dead_pocket_ic_transport_error(&error),
474                expected,
475            );
476            let wrapped = std::io::Error::other(error);
477            assert_eq!(
478                super::super::is_dead_pocket_ic_transport_error(&wrapped),
479                expected,
480            );
481        }
482    }
483
484    struct PanickingThenReporting {
485        calls: Cell<usize>,
486        request: Cell<Option<CanisterDiagnosticsRequest>>,
487    }
488
489    impl PocketIcDiagnosticsExt for PanickingThenReporting {
490        fn collect_canister_diagnostics(
491            &self,
492            request: CanisterDiagnosticsRequest,
493        ) -> CanisterDiagnosticsReport {
494            let call = self.calls.get();
495            self.calls.set(call + 1);
496            self.request.set(Some(request));
497            assert_ne!(call, 0, "synthetic first-entry diagnostic panic");
498            CanisterDiagnosticsReport {
499                request,
500                status: Err(PocketIcCallFailure::Operation(
501                    super::super::PocketIcOperationError::new("synthetic status failure"),
502                )),
503                logs: Err(PocketIcCallFailure::Operation(
504                    super::super::PocketIcOperationError::new("synthetic log failure"),
505                )),
506            }
507        }
508    }
509
510    struct PanickingWriter;
511
512    impl std::io::Write for PanickingWriter {
513        fn write(&mut self, _: &[u8]) -> std::io::Result<usize> {
514            panic!("synthetic writer panic");
515        }
516        fn flush(&mut self) -> std::io::Result<()> {
517            Ok(())
518        }
519    }
520
521    #[test]
522    fn explicit_reporting_preserves_requests_and_contains_secondary_failures() {
523        let collector = PanickingThenReporting {
524            calls: Cell::new(0),
525            request: Cell::new(None),
526        };
527        let request = CanisterDiagnosticsRequest {
528            canister_id: Principal::from_slice(&[1]),
529            status_sender: Principal::from_slice(&[2]),
530            log_sender: Principal::from_slice(&[3]),
531            log_limits: CanisterLogRenderLimits::default(),
532        };
533        let mut output = Vec::new();
534        let error = collector
535            .write_canister_diagnostics(request, "install", &mut output)
536            .expect_err("collection panic becomes secondary error");
537        assert_eq!(output, [] as [u8; 0]);
538        assert_eq!(collector.calls.get(), 1);
539        assert_eq!(collector.request.get(), Some(request));
540        assert!(
541            error
542                .get_ref()
543                .unwrap()
544                .downcast_ref::<super::super::PocketIcOperationError>()
545                .unwrap()
546                .message()
547                .contains("synthetic first-entry diagnostic panic")
548        );
549
550        collector
551            .write_canister_diagnostics(request, "install", &mut output)
552            .unwrap();
553        let text = String::from_utf8(output).unwrap();
554        assert!(text.starts_with("install: "));
555        assert!(
556            text.contains("synthetic status failure") && text.contains("synthetic log failure")
557        );
558        assert_eq!(collector.calls.get(), 2);
559        assert_eq!(collector.request.get(), Some(request));
560
561        let mut full_writer = std::io::Cursor::new([0_u8; 0]);
562        let error = collector
563            .write_canister_diagnostics(request, "install", &mut full_writer)
564            .expect_err("ordinary writer failure is retained");
565        assert_eq!(error.kind(), std::io::ErrorKind::WriteZero);
566        let error = collector
567            .write_canister_diagnostics(request, "install", &mut PanickingWriter)
568            .expect_err("writer panic becomes secondary error");
569        assert!(
570            error
571                .get_ref()
572                .unwrap()
573                .downcast_ref::<super::super::PocketIcOperationError>()
574                .unwrap()
575                .message()
576                .contains("synthetic writer panic")
577        );
578        assert_eq!(
579            collector.calls.get(),
580            4,
581            "one explicit collection per call, with no retries"
582        );
583    }
584
585    #[test]
586    fn labeled_batch_retains_order_and_continues_after_entry_panic() {
587        let collector = PanickingThenReporting {
588            calls: Cell::new(0),
589            request: Cell::new(None),
590        };
591        let first = CanisterDiagnosticsRequest {
592            canister_id: Principal::from_slice(&[1]),
593            status_sender: Principal::from_slice(&[2]),
594            log_sender: Principal::from_slice(&[3]),
595            log_limits: CanisterLogRenderLimits::default(),
596        };
597        let second = CanisterDiagnosticsRequest {
598            canister_id: Principal::from_slice(&[4]),
599            status_sender: Principal::from_slice(&[5]),
600            log_sender: Principal::from_slice(&[6]),
601            log_limits: CanisterLogRenderLimits::default(),
602        };
603        let report = collector
604            .collect_canister_diagnostics_batch(&[
605                LabeledCanisterDiagnosticsRequest {
606                    label: "root".into(),
607                    request: first,
608                },
609                LabeledCanisterDiagnosticsRequest {
610                    label: "worker".into(),
611                    request: second,
612                },
613            ])
614            .expect("valid labeled diagnostics batch");
615
616        assert_eq!(collector.calls.get(), 2);
617        assert_eq!(report.entries.len(), 2);
618        assert_eq!(report.entries[0].label, "root");
619        assert_eq!(report.entries[0].report.request, first);
620        assert_eq!(report.entries[1].label, "worker");
621        assert_eq!(report.entries[1].report.request, second);
622        assert!(
623            report
624                .entries
625                .iter()
626                .all(|entry| entry.entry_elapsed <= report.total)
627        );
628        assert_eq!(report.failures().count(), 2);
629        assert!(!report.is_success());
630        let compact = report.to_string();
631        assert!(compact.contains("label=\"root\""));
632        assert!(compact.contains("label=\"worker\""));
633        assert!(compact.contains("synthetic first-entry diagnostic panic"));
634    }
635
636    #[test]
637    fn diagnostic_batch_rejects_invalid_labels_before_collection() {
638        let collector = PanickingThenReporting {
639            calls: Cell::new(0),
640            request: Cell::new(None),
641        };
642        let request = CanisterDiagnosticsRequest {
643            canister_id: Principal::from_slice(&[1]),
644            status_sender: Principal::from_slice(&[2]),
645            log_sender: Principal::from_slice(&[3]),
646            log_limits: CanisterLogRenderLimits::default(),
647        };
648        let empty = collector
649            .collect_canister_diagnostics_batch(&[LabeledCanisterDiagnosticsRequest {
650                label: String::new(),
651                request,
652            }])
653            .expect_err("empty label must reject diagnostics batch");
654        assert_eq!(empty, BatchLabelError::Empty { index: 0 });
655        assert_eq!(collector.calls.get(), 0);
656
657        let duplicate = collector
658            .collect_canister_diagnostics_batch(&[
659                LabeledCanisterDiagnosticsRequest {
660                    label: "same".into(),
661                    request,
662                },
663                LabeledCanisterDiagnosticsRequest {
664                    label: "same".into(),
665                    request,
666                },
667            ])
668            .expect_err("duplicate labels must reject diagnostics batch");
669        assert_eq!(
670            duplicate,
671            BatchLabelError::Duplicate {
672                label: "same".to_owned(),
673                first_index: 0,
674                duplicate_index: 1,
675            }
676        );
677        assert_eq!(collector.calls.get(), 0);
678    }
679
680    #[test]
681    fn log_rendering_is_bounded_lossy_utf8_and_reports_truncation() {
682        let logs = render_log_records(
683            vec![
684                CanisterLogRecord {
685                    idx: 7,
686                    timestamp_nanos: 11,
687                    content: vec![b'f', 0x80, b'o'],
688                },
689                CanisterLogRecord {
690                    idx: 8,
691                    timestamp_nanos: 12,
692                    content: b"bar".to_vec(),
693                },
694            ],
695            CanisterLogRenderLimits {
696                record_limit: 1,
697                byte_limit: 2,
698            },
699        );
700
701        assert_eq!(logs.total_records(), 2);
702        assert_eq!(logs.total_content_bytes(), 6);
703        assert_eq!(logs.omitted_records(), 1);
704        assert_eq!(logs.omitted_content_bytes(), 4);
705        assert!(logs.was_truncated());
706        assert_eq!(logs.records().len(), 1);
707        assert_eq!(logs.records()[0].content(), "f�");
708        assert_eq!(logs.records()[0].original_content_bytes(), 3);
709        assert_eq!(logs.records()[0].omitted_content_bytes(), 1);
710        assert!(logs.records()[0].was_truncated());
711        let rendered = logs.to_string();
712        assert!(rendered.contains("f�"));
713        assert!(rendered.contains("truncated omitted_records=1 omitted_content_bytes=4"));
714    }
715
716    #[test]
717    fn zero_log_bounds_retain_only_aggregate_truncation() {
718        for (record_limit, byte_limit) in [(0, 0), (0, 16), (16, 0)] {
719            let logs = render_log_records(
720                vec![CanisterLogRecord {
721                    idx: 1,
722                    timestamp_nanos: 2,
723                    content: b"hello".to_vec(),
724                }],
725                CanisterLogRenderLimits {
726                    record_limit,
727                    byte_limit,
728                },
729            );
730
731            assert_eq!(logs.records(), []);
732            assert_eq!(logs.total_records(), 1);
733            assert_eq!(logs.total_content_bytes(), 5);
734            assert_eq!(logs.omitted_records(), 1);
735            assert_eq!(logs.omitted_content_bytes(), 5);
736            assert!(logs.was_truncated());
737            assert_eq!(
738                logs.to_string(),
739                "<no retained records>; truncated omitted_records=1 omitted_content_bytes=5"
740            );
741        }
742    }
743
744    #[test]
745    fn logs_within_bounds_preserve_empty_records_and_raw_byte_totals() {
746        let limits = CanisterLogRenderLimits {
747            record_limit: 3,
748            byte_limit: 3,
749        };
750        let empty = render_log_records(vec![], limits);
751        assert_eq!(empty.total_records(), 0);
752        assert_eq!(empty.total_content_bytes(), 0);
753        assert_eq!(empty.omitted_records(), 0);
754        assert_eq!(empty.omitted_content_bytes(), 0);
755        assert!(!empty.was_truncated());
756        assert_eq!(empty.to_string(), "<empty>");
757
758        let logs = render_log_records(
759            vec![
760                CanisterLogRecord {
761                    idx: 1,
762                    timestamp_nanos: 2,
763                    content: vec![],
764                },
765                CanisterLogRecord {
766                    idx: 3,
767                    timestamp_nanos: 4,
768                    content: vec![0x80, b'a'],
769                },
770                CanisterLogRecord {
771                    idx: 5,
772                    timestamp_nanos: 6,
773                    content: vec![],
774                },
775            ],
776            limits,
777        );
778        assert_eq!(logs.total_records(), 3);
779        assert_eq!(logs.records().len(), 3);
780        assert_eq!(logs.total_content_bytes(), 2);
781        assert_eq!(logs.records()[0].content(), "");
782        assert_eq!(logs.records()[1].content(), "�a");
783        assert_eq!(logs.records()[2].content(), "");
784        assert_eq!(logs.omitted_records(), 0);
785        assert_eq!(logs.omitted_content_bytes(), 0);
786        assert!(!logs.was_truncated());
787    }
788}