Line data Source code
1 : //! We re-export those from prometheus crate to
2 : //! make sure that we use the same dep version everywhere.
3 : //! Otherwise, we might not see all metrics registered via
4 : //! a default registry.
5 : #![deny(clippy::undocumented_unsafe_blocks)]
6 :
7 : use measured::label::{LabelGroupSet, LabelGroupVisitor, LabelName, NoLabels};
8 : use measured::metric::counter::CounterState;
9 : use measured::metric::gauge::GaugeState;
10 : use measured::metric::group::Encoding;
11 : use measured::metric::name::{MetricName, MetricNameEncoder};
12 : use measured::metric::{MetricEncoding, MetricFamilyEncoding};
13 : use measured::{FixedCardinalityLabel, LabelGroup, MetricGroup};
14 : use once_cell::sync::Lazy;
15 : use prometheus::Registry;
16 : use prometheus::core::{
17 : Atomic, AtomicU64, Collector, GenericCounter, GenericCounterVec, GenericGauge, GenericGaugeVec,
18 : };
19 : pub use prometheus::local::LocalHistogram;
20 : pub use prometheus::{
21 : Counter, CounterVec, Encoder, Error, Gauge, GaugeVec, Histogram, HistogramVec, IntCounter,
22 : IntCounterVec, IntGauge, IntGaugeVec, TextEncoder, core, default_registry, exponential_buckets,
23 : linear_buckets, opts, proto, register, register_counter_vec, register_gauge,
24 : register_gauge_vec, register_histogram, register_histogram_vec, register_int_counter,
25 : register_int_counter_vec, register_int_gauge, register_int_gauge_vec,
26 : };
27 :
28 : pub mod launch_timestamp;
29 : mod wrappers;
30 : pub use prometheus;
31 : pub use wrappers::{CountedReader, CountedWriter};
32 : mod hll;
33 : pub use hll::{HyperLogLog, HyperLogLogState, HyperLogLogVec};
34 : #[cfg(target_os = "linux")]
35 : pub mod more_process_metrics;
36 :
37 : pub type UIntGauge = GenericGauge<AtomicU64>;
38 : pub type UIntGaugeVec = GenericGaugeVec<AtomicU64>;
39 :
40 : #[macro_export]
41 : macro_rules! register_uint_gauge_vec {
42 : ($NAME:expr, $HELP:expr, $LABELS_NAMES:expr $(,)?) => {{
43 : let gauge_vec = UIntGaugeVec::new($crate::opts!($NAME, $HELP), $LABELS_NAMES).unwrap();
44 : $crate::register(Box::new(gauge_vec.clone())).map(|_| gauge_vec)
45 : }};
46 : }
47 :
48 : #[macro_export]
49 : macro_rules! register_uint_gauge {
50 : ($NAME:expr, $HELP:expr $(,)?) => {{
51 : let gauge = $crate::UIntGauge::new($NAME, $HELP).unwrap();
52 : $crate::register(Box::new(gauge.clone())).map(|_| gauge)
53 : }};
54 : }
55 :
56 : /// Special internal registry, to collect metrics independently from the default registry.
57 : /// Was introduced to fix deadlock with lazy registration of metrics in the default registry.
58 : static INTERNAL_REGISTRY: Lazy<Registry> = Lazy::new(Registry::new);
59 :
60 : /// Register a collector in the internal registry. MUST be called before the first call to `gather()`.
61 : ///
62 : /// Otherwise, we can have a deadlock in the `gather()` call, trying to register a new collector
63 : /// while holding the lock.
64 0 : pub fn register_internal(c: Box<dyn Collector>) -> prometheus::Result<()> {
65 0 : INTERNAL_REGISTRY.register(c)
66 0 : }
67 :
68 : /// Gathers all Prometheus metrics and records the I/O stats just before that.
69 : ///
70 : /// Metrics gathering is a relatively simple and standalone operation, so
71 : /// it might be fine to do it this way to keep things simple.
72 0 : pub fn gather() -> Vec<prometheus::proto::MetricFamily> {
73 0 : update_rusage_metrics();
74 0 : let mut mfs = prometheus::gather();
75 0 : let mut internal_mfs = INTERNAL_REGISTRY.gather();
76 0 : mfs.append(&mut internal_mfs);
77 0 : mfs
78 0 : }
79 :
80 0 : static DISK_IO_BYTES: Lazy<IntGaugeVec> = Lazy::new(|| {
81 0 : register_int_gauge_vec!(
82 : "libmetrics_disk_io_bytes_total",
83 : "Bytes written and read from disk, grouped by the operation (read|write)",
84 0 : &["io_operation"]
85 : )
86 0 : .expect("Failed to register disk i/o bytes int gauge vec")
87 0 : });
88 :
89 0 : static MAXRSS_KB: Lazy<IntGauge> = Lazy::new(|| {
90 0 : register_int_gauge!(
91 : "libmetrics_maxrss_kb",
92 : "Memory usage (Maximum Resident Set Size)"
93 : )
94 0 : .expect("Failed to register maxrss_kb int gauge")
95 0 : });
96 :
97 : /// Most common fsync latency is 50 µs - 100 µs, but it can be much higher,
98 : /// especially during many concurrent disk operations.
99 : pub const DISK_FSYNC_SECONDS_BUCKETS: &[f64] =
100 : &[0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 5.0, 10.0, 30.0];
101 :
102 : /// Constructs histogram buckets that are powers of two starting at 1 (i.e. 2^0), covering the end
103 : /// points. For example, passing start=5,end=20 yields 4,8,16,32 as does start=4,end=32.
104 29 : pub fn pow2_buckets(start: usize, end: usize) -> Vec<f64> {
105 29 : assert_ne!(start, 0);
106 28 : assert!(start <= end);
107 27 : let start = match start.checked_next_power_of_two() {
108 27 : Some(n) if n == start => n, // start already power of two
109 5 : Some(n) => n >> 1, // power of two below start
110 0 : None => panic!("start too large"),
111 : };
112 27 : let end = end.checked_next_power_of_two().expect("end too large");
113 191 : std::iter::successors(Some(start), |n| n.checked_mul(2))
114 191 : .take_while(|n| n <= &end)
115 168 : .map(|n| n as f64)
116 27 : .collect()
117 27 : }
118 :
119 : pub struct BuildInfo {
120 : pub revision: &'static str,
121 : pub build_tag: &'static str,
122 : }
123 :
124 : // todo: allow label group without the set
125 : impl LabelGroup for BuildInfo {
126 0 : fn visit_values(&self, v: &mut impl LabelGroupVisitor) {
127 : const REVISION: &LabelName = LabelName::from_str("revision");
128 0 : v.write_value(REVISION, &self.revision);
129 : const BUILD_TAG: &LabelName = LabelName::from_str("build_tag");
130 0 : v.write_value(BUILD_TAG, &self.build_tag);
131 0 : }
132 : }
133 :
134 : impl<T: Encoding> MetricFamilyEncoding<T> for BuildInfo
135 : where
136 : GaugeState: MetricEncoding<T>,
137 : {
138 0 : fn collect_family_into(
139 0 : &self,
140 0 : name: impl measured::metric::name::MetricNameEncoder,
141 0 : enc: &mut T,
142 0 : ) -> Result<(), T::Err> {
143 0 : enc.write_help(&name, "Build/version information")?;
144 0 : GaugeState::write_type(&name, enc)?;
145 0 : GaugeState {
146 0 : count: std::sync::atomic::AtomicI64::new(1),
147 0 : }
148 0 : .collect_into(&(), self, name, enc)
149 0 : }
150 : }
151 :
152 : #[derive(MetricGroup)]
153 : #[metric(new(build_info: BuildInfo))]
154 : pub struct NeonMetrics {
155 : #[cfg(target_os = "linux")]
156 : #[metric(namespace = "process")]
157 : #[metric(init = measured_process::ProcessCollector::for_self())]
158 : process: measured_process::ProcessCollector,
159 :
160 : #[metric(namespace = "libmetrics")]
161 : #[metric(init = LibMetrics::new(build_info))]
162 : libmetrics: LibMetrics,
163 : }
164 :
165 : #[derive(MetricGroup)]
166 : #[metric(new(build_info: BuildInfo))]
167 : pub struct LibMetrics {
168 : #[metric(init = build_info)]
169 : build_info: BuildInfo,
170 :
171 : #[metric(flatten)]
172 : rusage: Rusage,
173 :
174 : serve_count: CollectionCounter,
175 : }
176 :
177 0 : fn write_gauge<Enc: Encoding>(
178 0 : x: i64,
179 0 : labels: impl LabelGroup,
180 0 : name: impl MetricNameEncoder,
181 0 : enc: &mut Enc,
182 0 : ) -> Result<(), Enc::Err>
183 0 : where
184 0 : GaugeState: MetricEncoding<Enc>,
185 : {
186 0 : GaugeState::new(x).collect_into(&(), labels, name, enc)
187 0 : }
188 :
189 : #[derive(Default)]
190 : struct Rusage;
191 :
192 : #[derive(FixedCardinalityLabel, Clone, Copy)]
193 : #[label(singleton = "io_operation")]
194 : enum IoOp {
195 : Read,
196 : Write,
197 : }
198 :
199 : impl<T: Encoding> MetricGroup<T> for Rusage
200 : where
201 : GaugeState: MetricEncoding<T>,
202 : {
203 0 : fn collect_group_into(&self, enc: &mut T) -> Result<(), T::Err> {
204 : const DISK_IO: &MetricName = MetricName::from_str("disk_io_bytes_total");
205 : const MAXRSS: &MetricName = MetricName::from_str("maxrss_kb");
206 :
207 0 : let ru = get_rusage_stats();
208 :
209 0 : enc.write_help(
210 : DISK_IO,
211 0 : "Bytes written and read from disk, grouped by the operation (read|write)",
212 0 : )?;
213 0 : GaugeState::write_type(DISK_IO, enc)?;
214 0 : write_gauge(ru.ru_inblock * BYTES_IN_BLOCK, IoOp::Read, DISK_IO, enc)?;
215 0 : write_gauge(ru.ru_oublock * BYTES_IN_BLOCK, IoOp::Write, DISK_IO, enc)?;
216 :
217 0 : enc.write_help(MAXRSS, "Memory usage (Maximum Resident Set Size)")?;
218 0 : GaugeState::write_type(MAXRSS, enc)?;
219 0 : write_gauge(ru.ru_maxrss, IoOp::Read, MAXRSS, enc)?;
220 :
221 0 : Ok(())
222 0 : }
223 : }
224 :
225 : #[derive(Default)]
226 : struct CollectionCounter(CounterState);
227 :
228 : impl<T: Encoding> MetricFamilyEncoding<T> for CollectionCounter
229 : where
230 : CounterState: MetricEncoding<T>,
231 : {
232 0 : fn collect_family_into(
233 0 : &self,
234 0 : name: impl measured::metric::name::MetricNameEncoder,
235 0 : enc: &mut T,
236 0 : ) -> Result<(), T::Err> {
237 0 : self.0.inc();
238 0 : enc.write_help(&name, "Number of metric requests made")?;
239 0 : self.0.collect_into(&(), NoLabels, name, enc)
240 0 : }
241 : }
242 :
243 0 : pub fn set_build_info_metric(revision: &str, build_tag: &str) {
244 0 : let metric = register_int_gauge_vec!(
245 : "libmetrics_build_info",
246 : "Build/version information",
247 0 : &["revision", "build_tag"]
248 : )
249 0 : .expect("Failed to register build info metric");
250 0 : metric.with_label_values(&[revision, build_tag]).set(1);
251 0 : }
252 : const BYTES_IN_BLOCK: i64 = 512;
253 :
254 : // Records I/O stats in a "cross-platform" way.
255 : // Compiles both on macOS and Linux, but current macOS implementation always returns 0 as values for I/O stats.
256 : // An alternative is to read procfs (`/proc/[pid]/io`) which does not work under macOS at all, hence abandoned.
257 : //
258 : // Uses https://www.freebsd.org/cgi/man.cgi?query=getrusage to retrieve the number of block operations
259 : // performed by the process.
260 : // We know the size of the block, so we can determine the I/O bytes out of it.
261 : // The value might be not 100% exact, but should be fine for Prometheus metrics in this case.
262 0 : fn update_rusage_metrics() {
263 0 : let rusage_stats = get_rusage_stats();
264 :
265 0 : DISK_IO_BYTES
266 0 : .with_label_values(&["read"])
267 0 : .set(rusage_stats.ru_inblock * BYTES_IN_BLOCK);
268 0 : DISK_IO_BYTES
269 0 : .with_label_values(&["write"])
270 0 : .set(rusage_stats.ru_oublock * BYTES_IN_BLOCK);
271 :
272 : // On macOS, the unit of maxrss is bytes; on Linux, it's kilobytes. https://stackoverflow.com/a/59915669
273 : #[cfg(target_os = "macos")]
274 : {
275 : MAXRSS_KB.set(rusage_stats.ru_maxrss / 1024);
276 : }
277 : #[cfg(not(target_os = "macos"))]
278 0 : {
279 0 : MAXRSS_KB.set(rusage_stats.ru_maxrss);
280 0 : }
281 0 : }
282 :
283 0 : fn get_rusage_stats() -> libc::rusage {
284 0 : let mut rusage = std::mem::MaybeUninit::uninit();
285 :
286 : // SAFETY: kernel will initialize the struct for us
287 : unsafe {
288 0 : let ret = libc::getrusage(libc::RUSAGE_SELF, rusage.as_mut_ptr());
289 0 : assert!(ret == 0, "getrusage failed: bad args");
290 0 : rusage.assume_init()
291 : }
292 0 : }
293 :
294 : /// Create an [`IntCounterPairVec`] and registers to default registry.
295 : #[macro_export(local_inner_macros)]
296 : macro_rules! register_int_counter_pair_vec {
297 : ($NAME1:expr, $HELP1:expr, $NAME2:expr, $HELP2:expr, $LABELS_NAMES:expr $(,)?) => {{
298 : match (
299 : $crate::register_int_counter_vec!($NAME1, $HELP1, $LABELS_NAMES),
300 : $crate::register_int_counter_vec!($NAME2, $HELP2, $LABELS_NAMES),
301 : ) {
302 : (Ok(inc), Ok(dec)) => Ok($crate::IntCounterPairVec::new(inc, dec)),
303 : (Err(e), _) | (_, Err(e)) => Err(e),
304 : }
305 : }};
306 : }
307 :
308 : /// Create an [`IntCounterPair`] and registers to default registry.
309 : #[macro_export(local_inner_macros)]
310 : macro_rules! register_int_counter_pair {
311 : ($NAME1:expr, $HELP1:expr, $NAME2:expr, $HELP2:expr $(,)?) => {{
312 : match (
313 : $crate::register_int_counter!($NAME1, $HELP1),
314 : $crate::register_int_counter!($NAME2, $HELP2),
315 : ) {
316 : (Ok(inc), Ok(dec)) => Ok($crate::IntCounterPair::new(inc, dec)),
317 : (Err(e), _) | (_, Err(e)) => Err(e),
318 : }
319 : }};
320 : }
321 :
322 : /// A Pair of [`GenericCounterVec`]s. Like an [`GenericGaugeVec`] but will always observe changes
323 : pub struct GenericCounterPairVec<P: Atomic> {
324 : inc: GenericCounterVec<P>,
325 : dec: GenericCounterVec<P>,
326 : }
327 :
328 : /// A Pair of [`GenericCounter`]s. Like an [`GenericGauge`] but will always observe changes
329 : pub struct GenericCounterPair<P: Atomic> {
330 : inc: GenericCounter<P>,
331 : dec: GenericCounter<P>,
332 : }
333 :
334 : impl<P: Atomic> GenericCounterPairVec<P> {
335 226 : pub fn new(inc: GenericCounterVec<P>, dec: GenericCounterVec<P>) -> Self {
336 226 : Self { inc, dec }
337 0 : }
338 :
339 : /// `get_metric_with_label_values` returns the [`GenericCounterPair<P>`] for the given slice
340 : /// of label values (same order as the VariableLabels in Desc). If that combination of
341 : /// label values is accessed for the first time, a new [`GenericCounterPair<P>`] is created.
342 : ///
343 : /// An error is returned if the number of label values is not the same as the
344 : /// number of VariableLabels in Desc.
345 766 : pub fn get_metric_with_label_values(
346 766 : &self,
347 766 : vals: &[&str],
348 766 : ) -> prometheus::Result<GenericCounterPair<P>> {
349 : Ok(GenericCounterPair {
350 766 : inc: self.inc.get_metric_with_label_values(vals)?,
351 766 : dec: self.dec.get_metric_with_label_values(vals)?,
352 : })
353 0 : }
354 :
355 : /// `with_label_values` works as `get_metric_with_label_values`, but panics if an error
356 : /// occurs.
357 100 : pub fn with_label_values(&self, vals: &[&str]) -> GenericCounterPair<P> {
358 100 : self.get_metric_with_label_values(vals).unwrap()
359 0 : }
360 :
361 17 : pub fn remove_label_values(&self, res: &mut [prometheus::Result<()>; 2], vals: &[&str]) {
362 17 : res[0] = self.inc.remove_label_values(vals);
363 17 : res[1] = self.dec.remove_label_values(vals);
364 0 : }
365 : }
366 :
367 : impl<P: Atomic> GenericCounterPair<P> {
368 0 : pub fn new(inc: GenericCounter<P>, dec: GenericCounter<P>) -> Self {
369 0 : Self { inc, dec }
370 0 : }
371 :
372 : /// Increment the gauge by 1, returning a guard that decrements by 1 on drop.
373 113172 : pub fn guard(&self) -> GenericCounterPairGuard<P> {
374 113172 : self.inc.inc();
375 113172 : GenericCounterPairGuard(self.dec.clone())
376 0 : }
377 :
378 : /// Increment the gauge by n, returning a guard that decrements by n on drop.
379 0 : pub fn guard_by(&self, n: P::T) -> GenericCounterPairGuardBy<P> {
380 0 : self.inc.inc_by(n);
381 0 : GenericCounterPairGuardBy(self.dec.clone(), n)
382 0 : }
383 :
384 : /// Increase the gauge by 1.
385 : #[inline]
386 1970 : pub fn inc(&self) {
387 1970 : self.inc.inc();
388 0 : }
389 :
390 : /// Decrease the gauge by 1.
391 : #[inline]
392 1878 : pub fn dec(&self) {
393 1878 : self.dec.inc();
394 0 : }
395 :
396 : /// Add the given value to the gauge. (The value can be
397 : /// negative, resulting in a decrement of the gauge.)
398 : #[inline]
399 0 : pub fn inc_by(&self, v: P::T) {
400 0 : self.inc.inc_by(v);
401 0 : }
402 :
403 : /// Subtract the given value from the gauge. (The value can be
404 : /// negative, resulting in an increment of the gauge.)
405 : #[inline]
406 0 : pub fn dec_by(&self, v: P::T) {
407 0 : self.dec.inc_by(v);
408 0 : }
409 : }
410 :
411 : impl<P: Atomic> Clone for GenericCounterPair<P> {
412 3831 : fn clone(&self) -> Self {
413 3831 : Self {
414 3831 : inc: self.inc.clone(),
415 3831 : dec: self.dec.clone(),
416 3831 : }
417 0 : }
418 : }
419 :
420 : /// Guard returned by [`GenericCounterPair::guard`]
421 : pub struct GenericCounterPairGuard<P: Atomic>(GenericCounter<P>);
422 :
423 : impl<P: Atomic> Drop for GenericCounterPairGuard<P> {
424 113172 : fn drop(&mut self) {
425 113172 : self.0.inc();
426 0 : }
427 : }
428 : /// Guard returned by [`GenericCounterPair::guard_by`]
429 : pub struct GenericCounterPairGuardBy<P: Atomic>(GenericCounter<P>, P::T);
430 :
431 : impl<P: Atomic> Drop for GenericCounterPairGuardBy<P> {
432 0 : fn drop(&mut self) {
433 0 : self.0.inc_by(self.1);
434 0 : }
435 : }
436 :
437 : /// A Pair of [`IntCounterVec`]s. Like an [`IntGaugeVec`] but will always observe changes
438 : pub type IntCounterPairVec = GenericCounterPairVec<AtomicU64>;
439 :
440 : /// A Pair of [`IntCounter`]s. Like an [`IntGauge`] but will always observe changes
441 : pub type IntCounterPair = GenericCounterPair<AtomicU64>;
442 :
443 : /// A guard for [`IntCounterPair`] that will decrement the gauge on drop
444 : pub type IntCounterPairGuard = GenericCounterPairGuard<AtomicU64>;
445 :
446 : pub trait CounterPairAssoc {
447 : const INC_NAME: &'static MetricName;
448 : const DEC_NAME: &'static MetricName;
449 :
450 : const INC_HELP: &'static str;
451 : const DEC_HELP: &'static str;
452 :
453 : type LabelGroupSet: LabelGroupSet;
454 : }
455 :
456 : pub struct CounterPairVec<A: CounterPairAssoc> {
457 : vec: measured::metric::MetricVec<MeasuredCounterPairState, A::LabelGroupSet>,
458 : }
459 :
460 : impl<A: CounterPairAssoc> Default for CounterPairVec<A>
461 : where
462 : A::LabelGroupSet: Default,
463 : {
464 204 : fn default() -> Self {
465 204 : Self {
466 204 : vec: Default::default(),
467 204 : }
468 0 : }
469 : }
470 :
471 : impl<A: CounterPairAssoc> CounterPairVec<A> {
472 0 : pub fn guard(
473 0 : &self,
474 0 : labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>,
475 0 : ) -> MeasuredCounterPairGuard<'_, A> {
476 0 : let id = self.vec.with_labels(labels);
477 0 : self.vec.get_metric(id).inc.inc();
478 0 : MeasuredCounterPairGuard { vec: &self.vec, id }
479 0 : }
480 0 : pub fn inc(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>) {
481 0 : let id = self.vec.with_labels(labels);
482 0 : self.vec.get_metric(id).inc.inc();
483 0 : }
484 0 : pub fn dec(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>) {
485 0 : let id = self.vec.with_labels(labels);
486 0 : self.vec.get_metric(id).dec.inc();
487 0 : }
488 0 : pub fn remove_metric(
489 0 : &self,
490 0 : labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>,
491 0 : ) -> Option<MeasuredCounterPairState> {
492 0 : let id = self.vec.with_labels(labels);
493 0 : self.vec.remove_metric(id)
494 0 : }
495 :
496 0 : pub fn sample(&self, labels: <A::LabelGroupSet as LabelGroupSet>::Group<'_>) -> u64 {
497 0 : let id = self.vec.with_labels(labels);
498 0 : let metric = self.vec.get_metric(id);
499 :
500 0 : let inc = metric.inc.count.load(std::sync::atomic::Ordering::Relaxed);
501 0 : let dec = metric.dec.count.load(std::sync::atomic::Ordering::Relaxed);
502 0 : inc.saturating_sub(dec)
503 0 : }
504 : }
505 :
506 : impl<T, A> ::measured::metric::group::MetricGroup<T> for CounterPairVec<A>
507 : where
508 : T: ::measured::metric::group::Encoding,
509 : A: CounterPairAssoc,
510 : ::measured::metric::counter::CounterState: ::measured::metric::MetricEncoding<T>,
511 : {
512 0 : fn collect_group_into(&self, enc: &mut T) -> Result<(), T::Err> {
513 : // write decrement first to avoid a race condition where inc - dec < 0
514 0 : T::write_help(enc, A::DEC_NAME, A::DEC_HELP)?;
515 0 : self.vec
516 0 : .collect_family_into(A::DEC_NAME, &mut Dec(&mut *enc))?;
517 :
518 0 : T::write_help(enc, A::INC_NAME, A::INC_HELP)?;
519 0 : self.vec
520 0 : .collect_family_into(A::INC_NAME, &mut Inc(&mut *enc))?;
521 :
522 0 : Ok(())
523 0 : }
524 : }
525 :
526 : #[derive(MetricGroup, Default)]
527 : pub struct MeasuredCounterPairState {
528 : pub inc: CounterState,
529 : pub dec: CounterState,
530 : }
531 :
532 : impl measured::metric::MetricType for MeasuredCounterPairState {
533 : type Metadata = ();
534 : }
535 :
536 : pub struct MeasuredCounterPairGuard<'a, A: CounterPairAssoc> {
537 : vec: &'a measured::metric::MetricVec<MeasuredCounterPairState, A::LabelGroupSet>,
538 : id: measured::metric::LabelId<A::LabelGroupSet>,
539 : }
540 :
541 : impl<A: CounterPairAssoc> Drop for MeasuredCounterPairGuard<'_, A> {
542 0 : fn drop(&mut self) {
543 0 : self.vec.get_metric(self.id).dec.inc();
544 0 : }
545 : }
546 :
547 : /// [`MetricEncoding`] for [`MeasuredCounterPairState`] that only writes the inc counter to the inner encoder.
548 : struct Inc<T>(T);
549 : /// [`MetricEncoding`] for [`MeasuredCounterPairState`] that only writes the dec counter to the inner encoder.
550 : struct Dec<T>(T);
551 :
552 : impl<T: Encoding> Encoding for Inc<T> {
553 : type Err = T::Err;
554 :
555 0 : fn write_help(&mut self, name: impl MetricNameEncoder, help: &str) -> Result<(), Self::Err> {
556 0 : self.0.write_help(name, help)
557 0 : }
558 : }
559 :
560 : impl<T: Encoding> MetricEncoding<Inc<T>> for MeasuredCounterPairState
561 : where
562 : CounterState: MetricEncoding<T>,
563 : {
564 0 : fn write_type(name: impl MetricNameEncoder, enc: &mut Inc<T>) -> Result<(), T::Err> {
565 0 : CounterState::write_type(name, &mut enc.0)
566 0 : }
567 0 : fn collect_into(
568 0 : &self,
569 0 : metadata: &(),
570 0 : labels: impl LabelGroup,
571 0 : name: impl MetricNameEncoder,
572 0 : enc: &mut Inc<T>,
573 0 : ) -> Result<(), T::Err> {
574 0 : self.inc.collect_into(metadata, labels, name, &mut enc.0)
575 0 : }
576 : }
577 :
578 : impl<T: Encoding> Encoding for Dec<T> {
579 : type Err = T::Err;
580 :
581 0 : fn write_help(&mut self, name: impl MetricNameEncoder, help: &str) -> Result<(), Self::Err> {
582 0 : self.0.write_help(name, help)
583 0 : }
584 : }
585 :
586 : /// Write the dec counter to the encoder
587 : impl<T: Encoding> MetricEncoding<Dec<T>> for MeasuredCounterPairState
588 : where
589 : CounterState: MetricEncoding<T>,
590 : {
591 0 : fn write_type(name: impl MetricNameEncoder, enc: &mut Dec<T>) -> Result<(), T::Err> {
592 0 : CounterState::write_type(name, &mut enc.0)
593 0 : }
594 0 : fn collect_into(
595 0 : &self,
596 0 : metadata: &(),
597 0 : labels: impl LabelGroup,
598 0 : name: impl MetricNameEncoder,
599 0 : enc: &mut Dec<T>,
600 0 : ) -> Result<(), T::Err> {
601 0 : self.dec.collect_into(metadata, labels, name, &mut enc.0)
602 0 : }
603 : }
604 :
605 : #[cfg(test)]
606 : mod tests {
607 : use super::*;
608 :
609 : const POW2_BUCKETS_MAX: usize = 1 << (usize::BITS - 1);
610 :
611 : #[test]
612 1 : fn pow2_buckets_cases() {
613 1 : assert_eq!(pow2_buckets(1, 1), vec![1.0]);
614 1 : assert_eq!(pow2_buckets(1, 2), vec![1.0, 2.0]);
615 1 : assert_eq!(pow2_buckets(1, 3), vec![1.0, 2.0, 4.0]);
616 1 : assert_eq!(pow2_buckets(1, 4), vec![1.0, 2.0, 4.0]);
617 1 : assert_eq!(pow2_buckets(1, 5), vec![1.0, 2.0, 4.0, 8.0]);
618 1 : assert_eq!(pow2_buckets(1, 6), vec![1.0, 2.0, 4.0, 8.0]);
619 1 : assert_eq!(pow2_buckets(1, 7), vec![1.0, 2.0, 4.0, 8.0]);
620 1 : assert_eq!(pow2_buckets(1, 8), vec![1.0, 2.0, 4.0, 8.0]);
621 1 : assert_eq!(
622 1 : pow2_buckets(1, 200),
623 1 : vec![1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, 128.0, 256.0]
624 : );
625 :
626 1 : assert_eq!(pow2_buckets(1, 8), vec![1.0, 2.0, 4.0, 8.0]);
627 1 : assert_eq!(pow2_buckets(2, 8), vec![2.0, 4.0, 8.0]);
628 1 : assert_eq!(pow2_buckets(3, 8), vec![2.0, 4.0, 8.0]);
629 1 : assert_eq!(pow2_buckets(4, 8), vec![4.0, 8.0]);
630 1 : assert_eq!(pow2_buckets(5, 8), vec![4.0, 8.0]);
631 1 : assert_eq!(pow2_buckets(6, 8), vec![4.0, 8.0]);
632 1 : assert_eq!(pow2_buckets(7, 8), vec![4.0, 8.0]);
633 1 : assert_eq!(pow2_buckets(8, 8), vec![8.0]);
634 1 : assert_eq!(pow2_buckets(20, 200), vec![16.0, 32.0, 64.0, 128.0, 256.0]);
635 :
636 : // Largest valid values.
637 1 : assert_eq!(
638 1 : pow2_buckets(1, POW2_BUCKETS_MAX).len(),
639 : usize::BITS as usize
640 : );
641 1 : assert_eq!(pow2_buckets(POW2_BUCKETS_MAX, POW2_BUCKETS_MAX).len(), 1);
642 1 : }
643 :
644 : #[test]
645 : #[should_panic]
646 1 : fn pow2_buckets_zero_start() {
647 1 : pow2_buckets(0, 1);
648 1 : }
649 :
650 : #[test]
651 : #[should_panic]
652 1 : fn pow2_buckets_end_lt_start() {
653 1 : pow2_buckets(2, 1);
654 1 : }
655 :
656 : #[test]
657 : #[should_panic]
658 1 : fn pow2_buckets_end_overflow_min() {
659 1 : pow2_buckets(1, POW2_BUCKETS_MAX + 1);
660 1 : }
661 :
662 : #[test]
663 : #[should_panic]
664 1 : fn pow2_buckets_end_overflow_max() {
665 1 : pow2_buckets(1, usize::MAX);
666 1 : }
667 : }
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