/build/source/nativelink-util/src/metrics_utils.rs

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// Copyright 2024 The NativeLink Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::mem::forget;
use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
use std::thread_local;
use std::time::{Instant, SystemTime, UNIX_EPOCH};

use futures::Future;
use nativelink_metric::{
    group, publish, MetricFieldData, MetricKind, MetricPublishKnownKindData, MetricsComponent,
};

thread_local! {
    /// This is a thread local variable that will enable or disable metrics for
    /// the current thread. This does not mean that metrics are "disabled"
    /// everywhere. It only means that metrics gathering for this specific thread
    /// will be disabled. Because tokio uses thread pools, if you change this
    /// value you'll need to change it on every thread tokio is using, often using
    /// the `tokio::runtime::Builder::on_thread_start` function. This field also
    /// does not mean that metrics cannot be pulled from the registry. It only
    /// removes the ability for metrics that are collected at runtime (hot path)
    /// from being collected.
    pub static METRICS_ENABLED: AtomicBool = const { AtomicBool::new(true) };
}

#[inline]
pub fn metrics_enabled() -> bool {
    METRICS_ENABLED.with(
        #[inline]
        |v| v.load(Ordering::Acquire),
    )
}

/// This function will enable or disable metrics for the current thread.
/// WARNING: This will only happen for this thread. Tokio uses thread pools
/// so you'd need to run this function on every thread in the thread pool in
/// order to enable it everywhere.
pub fn set_metrics_enabled_for_this_thread(enabled: bool) {
    METRICS_ENABLED.with(|v| v.store(enabled, Ordering::Release));
}

#[derive(Default)]
pub struct FuncCounterWrapper {
    pub successes: AtomicU64,
    pub failures: AtomicU64,
}

impl FuncCounterWrapper {
    #[inline]
    pub fn wrap<T, E>(&self, func: impl FnOnce() -> Result<T, E>) -> Result<T, E> {
        let result = (func)();
        if result.is_ok() {
            self.successes.fetch_add(1, Ordering::Acquire);
        } else {
            self.failures.fetch_add(1, Ordering::Acquire);
        }
        result
    }
}

// Derive-macros have no way to tell the collector that the parent
// is now a group with the name of the group as the field so we
// can attach multiple values on the same group, so we need to
// manually implement the `MetricsComponent` trait to do so.
impl MetricsComponent for FuncCounterWrapper {
    fn publish(
        &self,
        _kind: MetricKind,
        field_metadata: MetricFieldData,
    ) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
        let _enter = group!(field_metadata.name).entered();

        publish!(
            "successes",
            &self.successes,
            MetricKind::Counter,
            format!(
                "The number of times {} was successful.",
                field_metadata.name
            )
        );
        publish!(
            "failures",
            &self.failures,
            MetricKind::Counter,
            format!("The number of times {} failed.", field_metadata.name)
        );

        Ok(MetricPublishKnownKindData::Component)
    }
}

/// This is a utility that will only increment the referenced counter when it is dropped.
/// This struct is zero cost and has a runtime cost only when it is dropped.
/// This struct is very useful for tracking when futures are dropped.
struct DropCounter<'a> {
    counter: &'a AtomicU64,
}

impl<'a> DropCounter<'a> {
    #[inline]
    pub fn new(counter: &'a AtomicU64) -> Self {
        Self { counter }
    }
}

impl<'a> Drop for DropCounter<'a> {
    #[inline]
    fn drop(&mut self) {
        if !metrics_enabled() {
            return;
        }
        self.counter.fetch_add(1, Ordering::Acquire);
    }
}

pub struct AsyncTimer<'a> {
    start: Instant,
    drop_counter: DropCounter<'a>,
    counter: &'a AsyncCounterWrapper,
}

impl<'a> AsyncTimer<'a> {
    #[inline]
    pub fn measure(self) {
        if !metrics_enabled() {
            return;
        }
        self.counter
            .sum_func_duration_ns
            .fetch_add(self.start.elapsed().as_nanos() as u64, Ordering::Acquire);
        self.counter.calls.fetch_add(1, Ordering::Acquire);
        self.counter.successes.fetch_add(1, Ordering::Acquire);
        // This causes DropCounter's drop to never be called.
        forget(self.drop_counter);
    }
}

/// Tracks the number of calls, successes, failures, and drops of an async function.
/// call `.wrap(future)` to wrap a future and stats about the future are automatically
/// tracked and can be published to a `CollectorState`.
#[derive(Default)]
pub struct AsyncCounterWrapper {
    pub calls: AtomicU64,
    pub successes: AtomicU64,
    pub failures: AtomicU64,
    pub drops: AtomicU64,
    // Time spent in nano seconds in the future.
    // 64 bit address space gives ~584 years of nanoseconds.
    pub sum_func_duration_ns: AtomicU64,
}

// Derive-macros have no way to tell the collector that the parent
// is now a group with the name of the group as the field so we
// can attach multiple values on the same group, so we need to
// manually implement the `MetricsComponent` trait to do so.
impl MetricsComponent for AsyncCounterWrapper {
    fn publish(
        &self,
        _kind: MetricKind,
        field_metadata: MetricFieldData,
    ) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
        let _enter = group!(field_metadata.name).entered();

        publish!(
            "calls",
            &self.calls,
            MetricKind::Counter,
            format!("The number of times {} was called.", field_metadata.name)
        );
        publish!(
            "successes",
            &self.successes,
            MetricKind::Counter,
            format!(
                "The number of times {} was successful.",
                field_metadata.name
            )
        );
        publish!(
            "failures",
            &self.failures,
            MetricKind::Counter,
            format!("The number of times {} failed.", field_metadata.name)
        );
        publish!(
            "drops",
            &self.drops,
            MetricKind::Counter,
            format!("The number of times {} was dropped.", field_metadata.name)
        );
        publish!(
            "sum_func_duration_ns",
            &self.sum_func_duration_ns,
            MetricKind::Counter,
            format!(
                "The sum of the time spent in nanoseconds in {}.",
                field_metadata.name
            )
        );

        Ok(MetricPublishKnownKindData::Component)
    }
}

impl AsyncCounterWrapper {
    #[inline]
    pub fn wrap_fn<'a, T: 'a, E>(
        &'a self,
        func: impl FnOnce() -> Result<T, E> + 'a,
    ) -> Result<T, E> {
        self.calls.fetch_add(1, Ordering::Acquire);
        let result = (func)();
        if result.is_ok() {
            self.successes.fetch_add(1, Ordering::Acquire);
        } else {
            self.failures.fetch_add(1, Ordering::Acquire);
        }
        result
    }

    #[inline]
    pub async fn wrap<'a, T, E, F: Future<Output = Result<T, E>> + 'a>(
        &'a self,
        future: F,
    ) -> Result<T, E> {
        if !metrics_enabled() {
            return future.await;
        }
        let result98 = self.wrap_no_capture_result(future)98.await;
        if result.is_ok() {
            self.successes.fetch_add(1, Ordering::Acquire);
        } else {
            self.failures.fetch_add(1, Ordering::Acquire);
        }
        result
    }

    #[inline]
    pub async fn wrap_no_capture_result<'a, T, F: Future<Output = T> + 'a>(
        &'a self,
        future: F,
    ) -> T {
        if !metrics_enabled() {
            return future.await;
        }
        self.calls.fetch_add(1, Ordering::Acquire);
        let drop_counter = DropCounter::new(&self.drops);
        let instant = Instant::now();
        let result98 = future98.await;
        // By default `drop_counter` will increment the drop counter when it goes out of scope.
        // This will ensure we don't increment the counter if we make it here with a zero cost.
        forget(drop_counter);
        self.sum_func_duration_ns
            .fetch_add(instant.elapsed().as_nanos() as u64, Ordering::Acquire);
        result
    }

    #[inline]
    pub fn begin_timer(&self) -> AsyncTimer<'_> {
        AsyncTimer {
            start: Instant::now(),
            drop_counter: DropCounter::new(&self.drops),
            counter: self,
        }
    }
}

/// Tracks an number.
#[derive(Default)]
pub struct Counter(AtomicU64);

impl Counter {
    #[inline]
    pub fn inc(&self) {
        self.add(1);
    }

    #[inline]
    pub fn add(&self, value: u64) {
        if !metrics_enabled() {
            return;
        }
        self.0.fetch_add(value, Ordering::Acquire);
    }

    #[inline]
    pub fn sub(&self, value: u64) {
        if !metrics_enabled() {
            return;
        }
        self.0.fetch_sub(value, Ordering::Acquire);
    }
}

impl MetricsComponent for Counter {
    fn publish(
        &self,
        kind: MetricKind,
        field_metadata: MetricFieldData,
    ) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
        self.0.publish(kind, field_metadata)
    }
}

/// Tracks an counter through time and the last time the counter was changed.
#[derive(Default)]
pub struct CounterWithTime {
    pub counter: AtomicU64,
    pub last_time: AtomicU64,
}

impl CounterWithTime {
    #[inline]
    pub fn inc(&self) {
        if !metrics_enabled() {
            return;
        }
        self.counter.fetch_add(1, Ordering::Acquire);
        self.last_time.store(
            SystemTime::now()
                .duration_since(UNIX_EPOCH)
                .unwrap()
                .as_secs(),
            Ordering::Release,
        );
    }
}

// Derive-macros have no way to tell the collector that the parent
// is now a group with the name of the group as the field so we
// can attach multiple values on the same group, so we need to
// manually implement the `MetricsComponent` trait to do so.
impl MetricsComponent for CounterWithTime {
    fn publish(
        &self,
        _kind: MetricKind,
        field_metadata: MetricFieldData,
    ) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
        let _enter = group!(field_metadata.name).entered();

        publish!(
            "counter",
            &self.counter,
            MetricKind::Counter,
            format!("Current count of {}.", field_metadata.name)
        );
        publish!(
            "last_time",
            &self.last_time,
            MetricKind::Counter,
            format!("Last timestamp {} was published.", field_metadata.name)
        );

        Ok(MetricPublishKnownKindData::Component)
    }
}

Coverage Report

Created: 2024-10-22 12:33

Line	Count	Source (jump to first uncovered line)
1		// Copyright 2024 The NativeLink Authors. All rights reserved.
2		//
3		// Licensed under the Apache License, Version 2.0 (the "License");
4		// you may not use this file except in compliance with the License.
5		// You may obtain a copy of the License at
6		//
7		// http://www.apache.org/licenses/LICENSE-2.0
8		//
9		// Unless required by applicable law or agreed to in writing, software
10		// distributed under the License is distributed on an "AS IS" BASIS,
11		// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12		// See the License for the specific language governing permissions and
13		// limitations under the License.
14
15		use std::mem::forget;
16		use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
17		use std::thread_local;
18		use std::time::{Instant, SystemTime, UNIX_EPOCH};
19
20		use futures::Future;
21		use nativelink_metric::{
22		group, publish, MetricFieldData, MetricKind, MetricPublishKnownKindData, MetricsComponent,
23		};
24
25		thread_local! {
26		/// This is a thread local variable that will enable or disable metrics for
27		/// the current thread. This does not mean that metrics are "disabled"
28		/// everywhere. It only means that metrics gathering for this specific thread
29		/// will be disabled. Because tokio uses thread pools, if you change this
30		/// value you'll need to change it on every thread tokio is using, often using
31		/// the `tokio::runtime::Builder::on_thread_start` function. This field also
32		/// does not mean that metrics cannot be pulled from the registry. It only
33		/// removes the ability for metrics that are collected at runtime (hot path)
34		/// from being collected.
35		pub static METRICS_ENABLED: AtomicBool = const { AtomicBool::new(true) };
36		}
37
38		#[inline]
39	6.19k	pub fn metrics_enabled() -> bool {
40	6.19k	METRICS_ENABLED.with(
41	6.19k	#[inline]
42	6.19k	\|v\| v.load(Ordering::Acquire),
43	6.19k	)
44	6.19k	}
45
46		/// This function will enable or disable metrics for the current thread.
47		/// WARNING: This will only happen for this thread. Tokio uses thread pools
48		/// so you'd need to run this function on every thread in the thread pool in
49		/// order to enable it everywhere.
50	0	pub fn set_metrics_enabled_for_this_thread(enabled: bool) {
51	0	METRICS_ENABLED.with(\|v\| v.store(enabled, Ordering::Release));
52	0	}
53
54		#[derive(Default)]
55		pub struct FuncCounterWrapper {
56		pub successes: AtomicU64,
57		pub failures: AtomicU64,
58		}
59
60		impl FuncCounterWrapper {
61		#[inline]
62	29	pub fn wrap<T, E>(&self, func: impl FnOnce() -> Result<T, E>) -> Result<T, E> {
63	29	let result = (func)();
64	29	if result.is_ok() { Branch (64:12): [True: 1, False: 0] Branch (64:12): [True: 27, False: 1] Branch (64:12): [Folded - Ignored] Branch (64:12): [Folded - Ignored]
65	28	self.successes.fetch_add(1, Ordering::Acquire);
66	28	} else {
67	1	self.failures.fetch_add(1, Ordering::Acquire);
68	1	}
69	29	result
70	29	}
71		}
72
73		// Derive-macros have no way to tell the collector that the parent
74		// is now a group with the name of the group as the field so we
75		// can attach multiple values on the same group, so we need to
76		// manually implement the `MetricsComponent` trait to do so.
77		impl MetricsComponent for FuncCounterWrapper {
78	0	fn publish(
79	0	&self,
80	0	_kind: MetricKind,
81	0	field_metadata: MetricFieldData,
82	0	) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
83	0	let _enter = group!(field_metadata.name).entered();
84	0
85	0	publish!(
86	0	"successes",
87	0	&self.successes,
88	0	MetricKind::Counter,
89	0	format!(
90	0	"The number of times {} was successful.",
91		field_metadata.name
92		)
93		);
94	0	publish!(
95	0	"failures",
96	0	&self.failures,
97	0	MetricKind::Counter,
98	0	format!("The number of times {} failed.", field_metadata.name)
99		);
100
101	0	Ok(MetricPublishKnownKindData::Component)
102	0	}
103		}
104
105		/// This is a utility that will only increment the referenced counter when it is dropped.
106		/// This struct is zero cost and has a runtime cost only when it is dropped.
107		/// This struct is very useful for tracking when futures are dropped.
108		struct DropCounter<'a> {
109		counter: &'a AtomicU64,
110		}
111
112		impl<'a> DropCounter<'a> {
113		#[inline]
114	0	pub fn new(counter: &'a AtomicU64) -> Self {
115	0	Self { counter }
116	0	}
117		}
118
119		impl<'a> Drop for DropCounter<'a> {
120		#[inline]
121	0	fn drop(&mut self) {
122	0	if !metrics_enabled() { Branch (122:12): [Folded - Ignored] Branch (122:12): [Folded - Ignored]
123	0	return;
124	0	}
125	0	self.counter.fetch_add(1, Ordering::Acquire);
126	0	}
127		}
128
129		pub struct AsyncTimer<'a> {
130		start: Instant,
131		drop_counter: DropCounter<'a>,
132		counter: &'a AsyncCounterWrapper,
133		}
134
135		impl<'a> AsyncTimer<'a> {
136		#[inline]
137	0	pub fn measure(self) {
138	0	if !metrics_enabled() { Branch (138:12): [Folded - Ignored] Branch (138:12): [Folded - Ignored]
139	0	return;
140	0	}
141	0	self.counter
142	0	.sum_func_duration_ns
143	0	.fetch_add(self.start.elapsed().as_nanos() as u64, Ordering::Acquire);
144	0	self.counter.calls.fetch_add(1, Ordering::Acquire);
145	0	self.counter.successes.fetch_add(1, Ordering::Acquire);
146	0	// This causes DropCounter's drop to never be called.
147	0	forget(self.drop_counter);
148	0	}
149		}
150
151		/// Tracks the number of calls, successes, failures, and drops of an async function.
152		/// call `.wrap(future)` to wrap a future and stats about the future are automatically
153		/// tracked and can be published to a `CollectorState`.
154		#[derive(Default)]
155		pub struct AsyncCounterWrapper {
156		pub calls: AtomicU64,
157		pub successes: AtomicU64,
158		pub failures: AtomicU64,
159		pub drops: AtomicU64,
160		// Time spent in nano seconds in the future.
161		// 64 bit address space gives ~584 years of nanoseconds.
162		pub sum_func_duration_ns: AtomicU64,
163		}
164
165		// Derive-macros have no way to tell the collector that the parent
166		// is now a group with the name of the group as the field so we
167		// can attach multiple values on the same group, so we need to
168		// manually implement the `MetricsComponent` trait to do so.
169		impl MetricsComponent for AsyncCounterWrapper {
170	0	fn publish(
171	0	&self,
172	0	_kind: MetricKind,
173	0	field_metadata: MetricFieldData,
174	0	) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
175	0	let _enter = group!(field_metadata.name).entered();
176	0
177	0	publish!(
178	0	"calls",
179	0	&self.calls,
180	0	MetricKind::Counter,
181	0	format!("The number of times {} was called.", field_metadata.name)
182		);
183	0	publish!(
184	0	"successes",
185	0	&self.successes,
186	0	MetricKind::Counter,
187	0	format!(
188	0	"The number of times {} was successful.",
189		field_metadata.name
190		)
191		);
192	0	publish!(
193	0	"failures",
194	0	&self.failures,
195	0	MetricKind::Counter,
196	0	format!("The number of times {} failed.", field_metadata.name)
197		);
198	0	publish!(
199	0	"drops",
200	0	&self.drops,
201	0	MetricKind::Counter,
202	0	format!("The number of times {} was dropped.", field_metadata.name)
203		);
204	0	publish!(
205	0	"sum_func_duration_ns",
206	0	&self.sum_func_duration_ns,
207	0	MetricKind::Counter,
208	0	format!(
209	0	"The sum of the time spent in nanoseconds in {}.",
210		field_metadata.name
211		)
212		);
213
214	0	Ok(MetricPublishKnownKindData::Component)
215	0	}
216		}
217
218		impl AsyncCounterWrapper {
219		#[inline]
220	0	pub fn wrap_fn<'a, T: 'a, E>(
221	0	&'a self,
222	0	func: impl FnOnce() -> Result<T, E> + 'a,
223	0	) -> Result<T, E> {
224	0	self.calls.fetch_add(1, Ordering::Acquire);
225	0	let result = (func)();
226	0	if result.is_ok() { Branch (226:12): [Folded - Ignored] Branch (226:12): [Folded - Ignored]
227	0	self.successes.fetch_add(1, Ordering::Acquire);
228	0	} else {
229	0	self.failures.fetch_add(1, Ordering::Acquire);
230	0	}
231	0	result
232	0	}
233
234		#[inline]
235	98	pub async fn wrap<'a, T, E, F: Future<Output = Result<T, E>> + 'a>(
236	98	&'a self,
237	98	future: F,
238	98	) -> Result<T, E> {
239	98	if !metrics_enabled() { Branch (239:12): [Folded - Ignored] Branch (239:12): [True: 0, False: 4] Branch (239:12): [Folded - Ignored] Branch (239:12): [True: 0, False: 6] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 14] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 5] Branch (239:12): [True: 0, False: 5] Branch (239:12): [True: 0, False: 5] Branch (239:12): [True: 0, False: 5] Branch (239:12): [True: 0, False: 5] Branch (239:12): [True: 0, False: 7] Branch (239:12): [True: 0, False: 7]
240	0	return future.await;
241	98	}
242	554	let result98 = self.wrap_no_capture_result(future)98 .await;
243	98	if result.is_ok() { Branch (243:12): [Folded - Ignored] Branch (243:12): [True: 3, False: 1] Branch (243:12): [Folded - Ignored] Branch (243:12): [True: 6, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 14, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 5, False: 0] Branch (243:12): [True: 5, False: 0] Branch (243:12): [True: 5, False: 0] Branch (243:12): [True: 5, False: 0] Branch (243:12): [True: 5, False: 0] Branch (243:12): [True: 7, False: 0] Branch (243:12): [True: 7, False: 0]
244	97	self.successes.fetch_add(1, Ordering::Acquire);
245	97	} else {
246	1	self.failures.fetch_add(1, Ordering::Acquire);
247	1	}
248	98	result
249	98	}
250
251		#[inline]
252	98	pub async fn wrap_no_capture_result<'a, T, F: Future<Output = T> + 'a>(
253	98	&'a self,
254	98	future: F,
255	98	) -> T {
256	98	if !metrics_enabled() { Branch (256:12): [Folded - Ignored] Branch (256:12): [True: 0, False: 4] Branch (256:12): [Folded - Ignored] Branch (256:12): [True: 0, False: 6] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 14] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 5] Branch (256:12): [True: 0, False: 5] Branch (256:12): [True: 0, False: 5] Branch (256:12): [True: 0, False: 5] Branch (256:12): [True: 0, False: 5] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 7] Branch (256:12): [True: 0, False: 0]
257	0	return future.await;
258	98	}
259	98	self.calls.fetch_add(1, Ordering::Acquire);
260	98	let drop_counter = DropCounter::new(&self.drops);
261	98	let instant = Instant::now();
262	554	let result98 = future98 .await;
263		// By default `drop_counter` will increment the drop counter when it goes out of scope.
264		// This will ensure we don't increment the counter if we make it here with a zero cost.
265	98	forget(drop_counter);
266	98	self.sum_func_duration_ns
267	98	.fetch_add(instant.elapsed().as_nanos() as u64, Ordering::Acquire);
268	98	result
269	98	}
270
271		#[inline]
272	0	pub fn begin_timer(&self) -> AsyncTimer<'_> {
273	0	AsyncTimer {
274	0	start: Instant::now(),
275	0	drop_counter: DropCounter::new(&self.drops),
276	0	counter: self,
277	0	}
278	0	}
279		}
280
281		/// Tracks an number.
282		#[derive(Default)]
283		pub struct Counter(AtomicU64);
284
285		impl Counter {
286		#[inline]
287	0	pub fn inc(&self) {
288	0	self.add(1);
289	0	}
290
291		#[inline]
292	5.90k	pub fn add(&self, value: u64) {
293	5.90k	if !metrics_enabled() { Branch (293:12): [True: 0, False: 5.90k] Branch (293:12): [Folded - Ignored]
294	0	return;
295	5.90k	}
296	5.90k	self.0.fetch_add(value, Ordering::Acquire);
297	5.90k	}
298
299		#[inline]
300	0	pub fn sub(&self, value: u64) {
301	0	if !metrics_enabled() { Branch (301:12): [Folded - Ignored] Branch (301:12): [Folded - Ignored]
302	0	return;
303	0	}
304	0	self.0.fetch_sub(value, Ordering::Acquire);
305	0	}
306		}
307
308		impl MetricsComponent for Counter {
309	0	fn publish(
310	0	&self,
311	0	kind: MetricKind,
312	0	field_metadata: MetricFieldData,
313	0	) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
314	0	self.0.publish(kind, field_metadata)
315	0	}
316		}
317
318		/// Tracks an counter through time and the last time the counter was changed.
319		#[derive(Default)]
320		pub struct CounterWithTime {
321		pub counter: AtomicU64,
322		pub last_time: AtomicU64,
323		}
324
325		impl CounterWithTime {
326		#[inline]
327	88	pub fn inc(&self) {
328	88	if !metrics_enabled() { Branch (328:12): [True: 0, False: 88] Branch (328:12): [Folded - Ignored]
329	0	return;
330	88	}
331	88	self.counter.fetch_add(1, Ordering::Acquire);
332	88	self.last_time.store(
333	88	SystemTime::now()
334	88	.duration_since(UNIX_EPOCH)
335	88	.unwrap()
336	88	.as_secs(),
337	88	Ordering::Release,
338	88	);
339	88	}
340		}
341
342		// Derive-macros have no way to tell the collector that the parent
343		// is now a group with the name of the group as the field so we
344		// can attach multiple values on the same group, so we need to
345		// manually implement the `MetricsComponent` trait to do so.
346		impl MetricsComponent for CounterWithTime {
347	0	fn publish(
348	0	&self,
349	0	_kind: MetricKind,
350	0	field_metadata: MetricFieldData,
351	0	) -> Result<MetricPublishKnownKindData, nativelink_metric::Error> {
352	0	let _enter = group!(field_metadata.name).entered();
353	0
354	0	publish!(
355	0	"counter",
356	0	&self.counter,
357	0	MetricKind::Counter,
358	0	format!("Current count of {}.", field_metadata.name)
359		);
360	0	publish!(
361	0	"last_time",
362	0	&self.last_time,
363	0	MetricKind::Counter,
364	0	format!("Last timestamp {} was published.", field_metadata.name)
365		);
366
367	0	Ok(MetricPublishKnownKindData::Component)
368	0	}
369		}