zlog.rs

  1//! # logger
  2pub use log as log_impl;
  3
  4pub const SCOPE_DEPTH_MAX: usize = 4;
  5
  6/// because we are currently just wrapping the `log` crate in `zlog`,
  7/// we need to work around the fact that the `log` crate only provides a
  8/// single global level filter. In order to have more precise control until
  9/// we no longer wrap `log`, we bump up the priority of log level so that it
 10/// will be logged, even if the actual level is lower
 11/// This is fine for now, as we use a `info` level filter by default in releases,
 12/// which hopefully won't result in confusion like `warn` or `error` levels might.
 13pub fn min_printed_log_level(level: log_impl::Level) -> log_impl::Level {
 14    // this logic is defined based on the logic used in the `log` crate,
 15    // which checks that a logs level is <= both of these values,
 16    // so we take the minimum of the two values to ensure that check passes
 17    let level_min_static = log_impl::STATIC_MAX_LEVEL;
 18    let level_min_dynamic = log_impl::max_level();
 19    if level <= level_min_static && level <= level_min_dynamic {
 20        return level;
 21    }
 22    return log_impl::LevelFilter::min(level_min_static, level_min_dynamic)
 23        .to_level()
 24        .unwrap_or(level);
 25}
 26
 27#[macro_export]
 28macro_rules! log {
 29    ($logger:expr, $level:expr, $($arg:tt)+) => {
 30        let level = $level;
 31        let logger = $logger;
 32        let (enabled, level) = $crate::scope_map::is_scope_enabled(&logger.scope, level);
 33        if enabled {
 34            $crate::log_impl::log!(level, "[{}]: {}", &logger.fmt_scope(), format!($($arg)+));
 35        }
 36    }
 37}
 38
 39#[macro_export]
 40macro_rules! trace {
 41    ($logger:expr => $($arg:tt)+) => {
 42        $crate::log!($logger, $crate::log_impl::Level::Trace, $($arg)+);
 43    };
 44    ($($arg:tt)+) => {
 45        $crate::log!($crate::default_logger!(), $crate::log_impl::Level::Trace, $($arg)+);
 46    };
 47}
 48
 49#[macro_export]
 50macro_rules! debug {
 51    ($logger:expr => $($arg:tt)+) => {
 52        $crate::log!($logger, $crate::log_impl::Level::Debug, $($arg)+);
 53    };
 54    ($($arg:tt)+) => {
 55        $crate::log!($crate::default_logger!(), $crate::log_impl::Level::Debug, $($arg)+);
 56    };
 57}
 58
 59#[macro_export]
 60macro_rules! info {
 61    ($logger:expr => $($arg:tt)+) => {
 62        $crate::log!($logger, $crate::log_impl::Level::Info, $($arg)+);
 63    };
 64    ($($arg:tt)+) => {
 65        $crate::log!($crate::default_logger!(), $crate::log_impl::Level::Info, $($arg)+);
 66    };
 67}
 68
 69#[macro_export]
 70macro_rules! warn {
 71    ($logger:expr => $($arg:tt)+) => {
 72        $crate::log!($logger, $crate::log_impl::Level::Warn, $($arg)+);
 73    };
 74    ($($arg:tt)+) => {
 75        $crate::log!($crate::default_logger!(), $crate::log_impl::Level::Warn, $($arg)+);
 76    };
 77}
 78
 79#[macro_export]
 80macro_rules! error {
 81    ($logger:expr => $($arg:tt)+) => {
 82        $crate::log!($logger, $crate::log_impl::Level::Error, $($arg)+);
 83    };
 84    ($($arg:tt)+) => {
 85        $crate::log!($crate::default_logger!(), $crate::log_impl::Level::Error, $($arg)+);
 86    };
 87}
 88
 89/// Creates a timer that logs the duration it was active for either when
 90/// it is dropped, or when explicitly stopped using the `end` method.
 91/// Logs at the `trace` level.
 92/// Note that it will include time spent across await points
 93/// (i.e. should not be used to measure the performance of async code)
 94/// However, this is a feature not a bug, as it allows for a more accurate
 95/// understanding of how long the action actually took to complete, including
 96/// interruptions, which can help explain why something may have timed out,
 97/// why it took longer to complete than it would had the await points resolved
 98/// immediately, etc.
 99#[macro_export]
100macro_rules! time {
101    ($logger:expr => $name:expr) => {
102        $crate::Timer::new($logger, $name)
103    };
104    ($name:expr) => {
105        time!($crate::default_logger!() => $name)
106    };
107}
108
109#[macro_export]
110macro_rules! scoped {
111    ($parent:expr => $name:expr) => {{
112        let parent = $parent;
113        let name = $name;
114        let mut scope = parent.scope;
115        let mut index = 1; // always have crate/module name
116        while index < scope.len() && !scope[index].is_empty() {
117            index += 1;
118        }
119        if index >= scope.len() {
120            #[cfg(debug_assertions)]
121            {
122                panic!("Scope overflow trying to add scope {}", name);
123            }
124            #[cfg(not(debug_assertions))]
125            {
126                $crate::warn!(
127                    parent =>
128                    "Scope overflow trying to add scope {}... ignoring scope",
129                    name
130                );
131            }
132        }
133        scope[index] = name;
134        $crate::Logger { scope }
135    }};
136    ($name:expr) => {
137        $crate::scoped!($crate::default_logger!() => $name)
138    };
139}
140
141#[macro_export]
142macro_rules! default_logger {
143    () => {
144        $crate::Logger {
145            scope: $crate::private::scope_new(&[$crate::crate_name!()]),
146        }
147    };
148}
149
150#[macro_export]
151macro_rules! crate_name {
152    () => {
153        $crate::private::extract_crate_name_from_module_path(module_path!())
154    };
155}
156
157/// functions that are used in macros, and therefore must be public,
158/// but should not be used directly
159pub mod private {
160    use super::*;
161
162    pub fn extract_crate_name_from_module_path(module_path: &'static str) -> &'static str {
163        return module_path
164            .split_once("::")
165            .map(|(crate_name, _)| crate_name)
166            .unwrap_or(module_path);
167    }
168
169    pub fn scope_new(scopes: &[&'static str]) -> Scope {
170        assert!(scopes.len() <= SCOPE_DEPTH_MAX);
171        let mut scope = [""; SCOPE_DEPTH_MAX];
172        scope[0..scopes.len()].copy_from_slice(scopes);
173        scope
174    }
175
176    pub fn scope_alloc_new(scopes: &[&str]) -> ScopeAlloc {
177        assert!(scopes.len() <= SCOPE_DEPTH_MAX);
178        let mut scope = [""; SCOPE_DEPTH_MAX];
179        scope[0..scopes.len()].copy_from_slice(scopes);
180        scope.map(|s| s.to_string())
181    }
182
183    pub fn scope_to_alloc(scope: &Scope) -> ScopeAlloc {
184        return scope.map(|s| s.to_string());
185    }
186}
187
188pub type Scope = [&'static str; SCOPE_DEPTH_MAX];
189pub type ScopeAlloc = [String; SCOPE_DEPTH_MAX];
190const SCOPE_STRING_SEP: &'static str = ".";
191
192#[derive(Clone, Copy, Debug, PartialEq, Eq)]
193pub struct Logger {
194    pub scope: Scope,
195}
196
197impl Logger {
198    pub fn fmt_scope(&self) -> String {
199        let mut last = 0;
200        for s in self.scope {
201            if s.is_empty() {
202                break;
203            }
204            last += 1;
205        }
206
207        return self.scope[0..last].join(SCOPE_STRING_SEP);
208    }
209}
210
211pub struct Timer {
212    pub logger: Logger,
213    pub start_time: std::time::Instant,
214    pub name: &'static str,
215    pub warn_if_longer_than: Option<std::time::Duration>,
216    pub done: bool,
217}
218
219impl Drop for Timer {
220    fn drop(&mut self) {
221        self.finish();
222    }
223}
224
225impl Timer {
226    #[must_use = "Timer will stop when dropped, the result of this function should be saved in a variable prefixed with `_` if it should stop when dropped"]
227    pub fn new(logger: Logger, name: &'static str) -> Self {
228        return Self {
229            logger,
230            name,
231            start_time: std::time::Instant::now(),
232            warn_if_longer_than: None,
233            done: false,
234        };
235    }
236    pub fn warn_if_gt(mut self, warn_limit: std::time::Duration) -> Self {
237        self.warn_if_longer_than = Some(warn_limit);
238        return self;
239    }
240
241    pub fn end(mut self) {
242        self.finish();
243    }
244
245    fn finish(&mut self) {
246        if self.done {
247            return;
248        }
249        let elapsed = self.start_time.elapsed();
250        if let Some(warn_limit) = self.warn_if_longer_than {
251            if elapsed > warn_limit {
252                crate::warn!(
253                    self.logger =>
254                    "Timer '{}' took {:?}. Which was longer than the expected limit of {:?}",
255                    self.name,
256                    elapsed,
257                    warn_limit
258                );
259                self.done = true;
260                return;
261            }
262        }
263        crate::trace!(
264            self.logger =>
265            "Timer '{}' finished in {:?}",
266            self.name,
267            elapsed
268        );
269        self.done = true;
270    }
271}
272
273pub mod scope_map {
274    use std::{
275        collections::{HashMap, VecDeque},
276        hash::{DefaultHasher, Hasher},
277        sync::{
278            atomic::{AtomicU64, Ordering},
279            RwLock,
280        },
281        usize,
282    };
283
284    use super::*;
285
286    static SCOPE_MAP: RwLock<Option<ScopeMap>> = RwLock::new(None);
287    static SCOPE_MAP_HASH: AtomicU64 = AtomicU64::new(0);
288
289    pub fn is_scope_enabled(scope: &Scope, level: log_impl::Level) -> (bool, log_impl::Level) {
290        let level_min = min_printed_log_level(level);
291        if level <= level_min {
292            // [FAST PATH]
293            // if the message is at or below the minimum printed log level
294            // (where error < warn < info etc) then always enable
295            return (true, level);
296        }
297
298        let Ok(map) = SCOPE_MAP.read() else {
299            // on failure, default to enabled detection done by `log` crate
300            return (true, level);
301        };
302
303        let Some(map) = map.as_ref() else {
304            // on failure, default to enabled detection done by `log` crate
305            return (true, level);
306        };
307
308        if map.is_empty() {
309            // if no scopes are enabled, default to enabled detection done by `log` crate
310            return (true, level);
311        }
312        let enabled_status = map.is_enabled(&scope, level);
313        match enabled_status {
314            EnabledStatus::NotConfigured => {
315                // if this scope isn't configured, default to enabled detection done by `log` crate
316                return (true, level);
317            }
318            EnabledStatus::Enabled => {
319                // if this scope is enabled, enable logging
320                // note: bumping level to min level that will be printed
321                // to work around log crate limitations
322                return (true, level_min);
323            }
324            EnabledStatus::Disabled => {
325                // if the configured level is lower than the requested level, disable logging
326                // note: err = 0, warn = 1, etc.
327                return (false, level);
328            }
329        }
330    }
331
332    fn hash_scope_map_settings(map: &HashMap<String, String>) -> u64 {
333        let mut hasher = DefaultHasher::new();
334        let mut items = map.iter().collect::<Vec<_>>();
335        items.sort();
336        for (key, value) in items {
337            Hasher::write(&mut hasher, key.as_bytes());
338            Hasher::write(&mut hasher, value.as_bytes());
339        }
340        return hasher.finish();
341    }
342
343    pub fn refresh(settings: &HashMap<String, String>) {
344        let hash_old = SCOPE_MAP_HASH.load(Ordering::Acquire);
345        let hash_new = hash_scope_map_settings(settings);
346        if hash_old == hash_new && hash_old != 0 {
347            return;
348        }
349        let map_new = ScopeMap::new_from_settings(settings);
350
351        if let Ok(_) = SCOPE_MAP_HASH.compare_exchange(
352            hash_old,
353            hash_new,
354            Ordering::Release,
355            Ordering::Relaxed,
356        ) {
357            let mut map = SCOPE_MAP.write().unwrap_or_else(|err| {
358                SCOPE_MAP.clear_poison();
359                err.into_inner()
360            });
361            *map = Some(map_new);
362        }
363    }
364
365    fn level_from_level_str(level_str: &String) -> Option<log_impl::Level> {
366        let level = match level_str.to_ascii_lowercase().as_str() {
367            "" => log_impl::Level::Trace,
368            "trace" => log_impl::Level::Trace,
369            "debug" => log_impl::Level::Debug,
370            "info" => log_impl::Level::Info,
371            "warn" => log_impl::Level::Warn,
372            "error" => log_impl::Level::Error,
373            "off" | "disable" | "no" | "none" | "disabled" => {
374                crate::warn!("Invalid log level \"{level_str}\", set to error to disable non-error logging. Defaulting to error");
375                log_impl::Level::Error
376            }
377            _ => {
378                crate::warn!("Invalid log level \"{level_str}\", ignoring");
379                return None;
380            }
381        };
382        return Some(level);
383    }
384
385    fn scope_alloc_from_scope_str(scope_str: &String) -> Option<ScopeAlloc> {
386        let mut scope_buf = [""; SCOPE_DEPTH_MAX];
387        let mut index = 0;
388        let mut scope_iter = scope_str.split(SCOPE_STRING_SEP);
389        while index < SCOPE_DEPTH_MAX {
390            let Some(scope) = scope_iter.next() else {
391                break;
392            };
393            if scope == "" {
394                continue;
395            }
396            scope_buf[index] = scope;
397            index += 1;
398        }
399        if index == 0 {
400            return None;
401        }
402        if let Some(_) = scope_iter.next() {
403            crate::warn!(
404                "Invalid scope key, too many nested scopes: '{scope_str}'. Max depth is {SCOPE_DEPTH_MAX}",
405            );
406            return None;
407        }
408        let scope = scope_buf.map(|s| s.to_string());
409        return Some(scope);
410    }
411
412    pub struct ScopeMap {
413        entries: Vec<ScopeMapEntry>,
414        root_count: usize,
415    }
416
417    pub struct ScopeMapEntry {
418        scope: String,
419        enabled: Option<log_impl::Level>,
420        descendants: std::ops::Range<usize>,
421    }
422
423    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
424    pub enum EnabledStatus {
425        Enabled,
426        Disabled,
427        NotConfigured,
428    }
429
430    impl ScopeMap {
431        pub fn new_from_settings(items_input_map: &HashMap<String, String>) -> Self {
432            let mut items = items_input_map
433                .into_iter()
434                .filter_map(|(scope_str, level_str)| {
435                    let scope = scope_alloc_from_scope_str(&scope_str)?;
436                    let level = level_from_level_str(&level_str)?;
437                    return Some((scope, level));
438                })
439                .collect::<Vec<_>>();
440
441            items.sort_by(|a, b| a.0.cmp(&b.0));
442
443            let mut this = Self {
444                entries: Vec::with_capacity(items.len() * SCOPE_DEPTH_MAX),
445                root_count: 0,
446            };
447
448            let items_count = items.len();
449
450            struct ProcessQueueEntry {
451                parent_index: usize,
452                depth: usize,
453                items_range: std::ops::Range<usize>,
454            }
455            let mut process_queue = VecDeque::new();
456            process_queue.push_back(ProcessQueueEntry {
457                parent_index: usize::MAX,
458                depth: 0,
459                items_range: 0..items_count,
460            });
461
462            let empty_range = 0..0;
463
464            while let Some(process_entry) = process_queue.pop_front() {
465                let ProcessQueueEntry {
466                    items_range,
467                    depth,
468                    parent_index,
469                } = process_entry;
470                let mut cursor = items_range.start;
471                let res_entries_start = this.entries.len();
472                while cursor < items_range.end {
473                    let sub_items_start = cursor;
474                    cursor += 1;
475                    let scope_name = &items[sub_items_start].0[depth];
476                    while cursor < items_range.end && &items[cursor].0[depth] == scope_name {
477                        cursor += 1;
478                    }
479                    let sub_items_end = cursor;
480                    if scope_name == "" {
481                        assert_eq!(sub_items_start + 1, sub_items_end);
482                        assert_ne!(depth, 0);
483                        assert_ne!(parent_index, usize::MAX);
484                        assert!(this.entries[parent_index].enabled.is_none());
485                        this.entries[parent_index].enabled = Some(items[sub_items_start].1);
486                        continue;
487                    }
488                    let is_valid_scope = scope_name != "";
489                    let is_last = depth + 1 == SCOPE_DEPTH_MAX || !is_valid_scope;
490                    let mut enabled = None;
491                    if is_last {
492                        assert_eq!(sub_items_start + 1, sub_items_end);
493                        enabled = Some(items[sub_items_start].1);
494                    } else {
495                        let entry_index = this.entries.len();
496                        process_queue.push_back(ProcessQueueEntry {
497                            items_range: sub_items_start..sub_items_end,
498                            parent_index: entry_index,
499                            depth: depth + 1,
500                        });
501                    }
502                    this.entries.push(ScopeMapEntry {
503                        scope: scope_name.to_owned(),
504                        enabled,
505                        descendants: empty_range.clone(),
506                    });
507                }
508                let res_entries_end = this.entries.len();
509                if parent_index != usize::MAX {
510                    this.entries[parent_index].descendants = res_entries_start..res_entries_end;
511                } else {
512                    this.root_count = res_entries_end;
513                }
514            }
515
516            return this;
517        }
518
519        pub fn is_empty(&self) -> bool {
520            self.entries.is_empty()
521        }
522
523        pub fn is_enabled<S>(
524            &self,
525            scope: &[S; SCOPE_DEPTH_MAX],
526            level: log_impl::Level,
527        ) -> EnabledStatus
528        where
529            S: AsRef<str>,
530        {
531            let mut enabled = None;
532            let mut cur_range = &self.entries[0..self.root_count];
533            let mut depth = 0;
534
535            'search: while !cur_range.is_empty()
536                && depth < SCOPE_DEPTH_MAX
537                && scope[depth].as_ref() != ""
538            {
539                for entry in cur_range {
540                    if entry.scope == scope[depth].as_ref() {
541                        // note:
542                        enabled = entry.enabled.or(enabled);
543                        cur_range = &self.entries[entry.descendants.clone()];
544                        depth += 1;
545                        continue 'search;
546                    }
547                }
548                break 'search;
549            }
550
551            return enabled.map_or(EnabledStatus::NotConfigured, |level_enabled| {
552                if level <= level_enabled {
553                    EnabledStatus::Enabled
554                } else {
555                    EnabledStatus::Disabled
556                }
557            });
558        }
559    }
560
561    #[cfg(test)]
562    mod tests {
563        use super::*;
564
565        fn scope_map_from_keys(kv: &[(&str, &str)]) -> ScopeMap {
566            let hash_map: HashMap<String, String> = kv
567                .iter()
568                .map(|(k, v)| (k.to_string(), v.to_string()))
569                .collect();
570            ScopeMap::new_from_settings(&hash_map)
571        }
572
573        #[test]
574        fn test_initialization() {
575            let map = scope_map_from_keys(&[("a.b.c.d", "trace")]);
576            assert_eq!(map.root_count, 1);
577            assert_eq!(map.entries.len(), 4);
578
579            let map = scope_map_from_keys(&[]);
580            assert_eq!(map.root_count, 0);
581            assert_eq!(map.entries.len(), 0);
582
583            let map = scope_map_from_keys(&[("", "trace")]);
584            assert_eq!(map.root_count, 0);
585            assert_eq!(map.entries.len(), 0);
586
587            let map = scope_map_from_keys(&[("foo..bar", "trace")]);
588            assert_eq!(map.root_count, 1);
589            assert_eq!(map.entries.len(), 2);
590
591            let map = scope_map_from_keys(&[
592                ("a.b.c.d", "trace"),
593                ("e.f.g.h", "debug"),
594                ("i.j.k.l", "info"),
595                ("m.n.o.p", "warn"),
596                ("q.r.s.t", "error"),
597            ]);
598            assert_eq!(map.root_count, 5);
599            assert_eq!(map.entries.len(), 20);
600            assert_eq!(map.entries[0].scope, "a");
601            assert_eq!(map.entries[1].scope, "e");
602            assert_eq!(map.entries[2].scope, "i");
603            assert_eq!(map.entries[3].scope, "m");
604            assert_eq!(map.entries[4].scope, "q");
605        }
606
607        fn scope_from_scope_str(scope_str: &'static str) -> Scope {
608            let mut scope_buf = [""; SCOPE_DEPTH_MAX];
609            let mut index = 0;
610            let mut scope_iter = scope_str.split(SCOPE_STRING_SEP);
611            while index < SCOPE_DEPTH_MAX {
612                let Some(scope) = scope_iter.next() else {
613                    break;
614                };
615                if scope == "" {
616                    continue;
617                }
618                scope_buf[index] = scope;
619                index += 1;
620            }
621            assert_ne!(index, 0);
622            assert!(scope_iter.next().is_none());
623            return scope_buf;
624        }
625
626        #[test]
627        fn test_is_enabled() {
628            let map = scope_map_from_keys(&[
629                ("a.b.c.d", "trace"),
630                ("e.f.g.h", "debug"),
631                ("i.j.k.l", "info"),
632                ("m.n.o.p", "warn"),
633                ("q.r.s.t", "error"),
634            ]);
635            use log_impl::Level;
636            assert_eq!(
637                map.is_enabled(&scope_from_scope_str("a.b.c.d"), Level::Trace),
638                EnabledStatus::Enabled
639            );
640            assert_eq!(
641                map.is_enabled(&scope_from_scope_str("a.b.c.d"), Level::Debug),
642                EnabledStatus::Enabled
643            );
644
645            assert_eq!(
646                map.is_enabled(&scope_from_scope_str("e.f.g.h"), Level::Debug),
647                EnabledStatus::Enabled
648            );
649            assert_eq!(
650                map.is_enabled(&scope_from_scope_str("e.f.g.h"), Level::Info),
651                EnabledStatus::Enabled
652            );
653            assert_eq!(
654                map.is_enabled(&scope_from_scope_str("e.f.g.h"), Level::Trace),
655                EnabledStatus::Disabled
656            );
657
658            assert_eq!(
659                map.is_enabled(&scope_from_scope_str("i.j.k.l"), Level::Info),
660                EnabledStatus::Enabled
661            );
662            assert_eq!(
663                map.is_enabled(&scope_from_scope_str("i.j.k.l"), Level::Warn),
664                EnabledStatus::Enabled
665            );
666            assert_eq!(
667                map.is_enabled(&scope_from_scope_str("i.j.k.l"), Level::Debug),
668                EnabledStatus::Disabled
669            );
670
671            assert_eq!(
672                map.is_enabled(&scope_from_scope_str("m.n.o.p"), Level::Warn),
673                EnabledStatus::Enabled
674            );
675            assert_eq!(
676                map.is_enabled(&scope_from_scope_str("m.n.o.p"), Level::Error),
677                EnabledStatus::Enabled
678            );
679            assert_eq!(
680                map.is_enabled(&scope_from_scope_str("m.n.o.p"), Level::Info),
681                EnabledStatus::Disabled
682            );
683
684            assert_eq!(
685                map.is_enabled(&scope_from_scope_str("q.r.s.t"), Level::Error),
686                EnabledStatus::Enabled
687            );
688            assert_eq!(
689                map.is_enabled(&scope_from_scope_str("q.r.s.t"), Level::Warn),
690                EnabledStatus::Disabled
691            );
692        }
693    }
694}
695
696#[cfg(test)]
697mod tests {
698    use super::*;
699
700    #[test]
701    fn test_crate_name() {
702        assert_eq!(crate_name!(), "zlog");
703    }
704}