metrics: add basic ods support to Counter

Summary:
Now (when compiled by buck in fbsource) the Counter type also contains an ODS counter that gets updated as the Counter is updated.

Rather than using the dynamic counter in stats::define_stats macro, I directly instantiate a BoxSingletonCounter and store it in the Counter. This avoids computing the String metric name every time when incrementing.

Reviewed By: quark-zju

Differential Revision: D66848953

fbshipit-source-id: 71858669fb3c4e55339ed52bd2a5023aa7927e6b

eden/scm/lib/metrics/Cargo.toml

@@ -13,6 +13,13 @@ license = "MIT"
 name = "metrics"
 
 [dependencies]
+fbinit = { version = "0.2.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main", optional = true }
 futures = { version = "0.3.30", features = ["async-await", "compat"] }
 once_cell = "1.12"
 parking_lot = { version = "0.12.1", features = ["send_guard"] }
+stats = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main", optional = true }
+stats_traits = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main", optional = true }
+
+[features]
+default = []
+ods = ["fbinit", "stats", "stats_traits"]

eden/scm/lib/metrics/src/dummy_ods.rs

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+pub(crate) type Counter = ();
+
+pub(crate) fn new_counter(_name: &'static str) -> Counter {
+    ()
+}
+
+pub(crate) fn increment(_counter: &Counter, _value: i64) {}

eden/scm/lib/metrics/src/lib.rs

@@ -14,9 +14,12 @@ use once_cell::sync::Lazy;
 use once_cell::sync::OnceCell;
 use parking_lot::RwLock;
 
+#[cfg_attr(not(feature = "ods"), path = "dummy_ods.rs")]
+mod ods;
+
 pub struct Counter {
     name: &'static str,
-    counter: OnceCell<AtomicUsize>,
+    counter: OnceCell<(AtomicUsize, ods::Counter)>,
     gauge: bool,
 }
 
@@ -43,15 +46,19 @@ impl Counter {
     }
 
     pub fn add(&'static self, val: usize) {
-        self.counter().fetch_add(val, Ordering::Relaxed);
+        let (counter, ods) = self.counter();
+        counter.fetch_add(val, Ordering::Relaxed);
+        ods::increment(ods, val as i64);
     }
 
     pub fn sub(&'static self, val: usize) {
-        self.counter().fetch_sub(val, Ordering::Relaxed);
+        let (counter, ods) = self.counter();
+        counter.fetch_sub(val, Ordering::Relaxed);
+        ods::increment(ods, -(val as i64));
     }
 
     pub fn value(&'static self) -> usize {
-        self.counter().load(Ordering::Relaxed)
+        self.counter().0.load(Ordering::Relaxed)
     }
 
     /// Increment counter by v and decrement it back by v when returned guard is dropped
@@ -64,10 +71,10 @@ impl Counter {
         self.gauge
     }
 
-    fn counter(&'static self) -> &AtomicUsize {
+    fn counter(&'static self) -> &(AtomicUsize, ods::Counter) {
         self.counter.get_or_init(|| {
             Registry::global().register_counter(self);
-            AtomicUsize::new(0)
+            (AtomicUsize::new(0), ods::new_counter(self.name))
         })
     }
 }
@@ -115,7 +122,7 @@ impl Registry {
 
     pub fn reset(&self) {
         for counter in self.counters.read().values() {
-            counter.counter().store(0, Ordering::Relaxed);
+            counter.counter().0.store(0, Ordering::Relaxed);
         }
     }
 }

eden/scm/lib/metrics/src/ods.rs

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+pub(crate) type Counter = stats_traits::stat_types::BoxSingletonCounter;
+
+pub(crate) fn new_counter(name: &'static str) -> Counter {
+    stats::create_singleton_counter(name.to_string())
+}
+
+pub(crate) fn increment(counter: &Counter, value: i64) {
+    if !fbinit::was_performed() {
+        return;
+    }
+
+    counter.increment_value(fbinit::expect_init(), value);
+}