From 818daa5c786813fdf50fecb6022e29b18e509b62 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 22 Feb 2022 13:53:59 +0100
Subject: Refactor how durations are measured

---
 src/util/Cargo.toml |  2 ++
 src/util/lib.rs     |  1 +
 src/util/metrics.rs | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+)
 create mode 100644 src/util/metrics.rs

(limited to 'src/util')

diff --git a/src/util/Cargo.toml b/src/util/Cargo.toml
index 76b73f4b..e1d516de 100644
--- a/src/util/Cargo.toml
+++ b/src/util/Cargo.toml
@@ -42,3 +42,5 @@ hyper = "0.14"
 
 kube = { version = "0.62", features = ["runtime", "derive"] }
 k8s-openapi = { version = "0.13", features = ["v1_22"] }
+
+opentelemetry = "0.17"
diff --git a/src/util/lib.rs b/src/util/lib.rs
index 6856f656..7ed00034 100644
--- a/src/util/lib.rs
+++ b/src/util/lib.rs
@@ -8,6 +8,7 @@ pub mod config;
 pub mod crdt;
 pub mod data;
 pub mod error;
+pub mod metrics;
 pub mod persister;
 pub mod time;
 pub mod token_bucket;
diff --git a/src/util/metrics.rs b/src/util/metrics.rs
new file mode 100644
index 00000000..b3b1fc3c
--- /dev/null
+++ b/src/util/metrics.rs
@@ -0,0 +1,35 @@
+use std::time::SystemTime;
+
+use futures::{future::BoxFuture, Future, FutureExt};
+
+use opentelemetry::{KeyValue, metrics::*};
+
+pub trait RecordDuration<'a>: 'a {
+	type Output;
+
+	fn record_duration(self, r: &'a ValueRecorder<f64>, attributes: &'a [KeyValue]) -> BoxFuture<'a, Self::Output>;
+	fn bound_record_duration(self, r: &'a BoundValueRecorder<f64>) -> BoxFuture<'a, Self::Output>;
+}
+
+impl<'a, T, O> RecordDuration<'a> for T
+where T: Future<Output=O> + Send + 'a {
+	type Output = O;
+
+	fn record_duration(self, r: &'a ValueRecorder<f64>, attributes: &'a [KeyValue]) -> BoxFuture<'a, Self::Output> {
+		async move {
+			let request_start = SystemTime::now();
+			let res = self.await;
+			r.record(request_start.elapsed().map_or(0.0, |d| d.as_secs_f64()), attributes);
+			res
+		}.boxed()
+	}
+
+	fn bound_record_duration(self, r: &'a BoundValueRecorder<f64>) -> BoxFuture<'a, Self::Output> {
+		async move {
+			let request_start = SystemTime::now();
+			let res = self.await;
+			r.record(request_start.elapsed().map_or(0.0, |d| d.as_secs_f64()));
+			res
+		}.boxed()
+	}
+}
-- 
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