otel metrics: define histogram buckets the same as before

src/cdn.rs

@@ -1,4 +1,8 @@
-use crate::{Config, InstanceMetrics, metrics::otel::AnyMeterProvider, utils::report_error};
+use crate::{
+    Config, InstanceMetrics,
+    metrics::{CDN_INVALIDATION_HISTOGRAM_BUCKETS, otel::AnyMeterProvider},
+    utils::report_error,
+};
 use anyhow::{Context, Error, Result, anyhow, bail};
 use aws_config::BehaviorVersion;
 use aws_sdk_cloudfront::{
@@ -38,10 +42,12 @@ impl CdnMetrics {
         Self {
             invalidation_time: meter
                 .f64_histogram(format!("{PREFIX}.invalidation_time"))
+                .with_boundaries(CDN_INVALIDATION_HISTOGRAM_BUCKETS.to_vec())
                 .with_unit("s")
                 .build(),
             queue_time: meter
                 .f64_histogram(format!("{PREFIX}.queue_time"))
+                .with_boundaries(CDN_INVALIDATION_HISTOGRAM_BUCKETS.to_vec())
                 .with_unit("s")
                 .build(),
         }

src/docbuilder/rustwide_builder.rs

@@ -11,7 +11,7 @@ use crate::{
     },
     docbuilder::Limits,
     error::Result,
-    metrics::otel::AnyMeterProvider,
+    metrics::{BUILD_TIME_HISTOGRAM_BUCKETS, DOCUMENTATION_SIZE_BUCKETS, otel::AnyMeterProvider},
     repositories::RepositoryStatsUpdater,
     storage::{
         CompressionAlgorithm, RustdocJsonFormatVersion, compress, get_file_list,
@@ -136,6 +136,7 @@ impl BuilderMetrics {
                 .build(),
             build_time: meter
                 .f64_histogram(format!("{PREFIX}.build_time"))
+                .with_boundaries(BUILD_TIME_HISTOGRAM_BUCKETS.to_vec())
                 .with_unit("s")
                 .build(),
             total_builds: meter
@@ -152,6 +153,7 @@ impl BuilderMetrics {
                 .build(),
             documentation_size: meter
                 .u64_histogram(format!("{PREFIX}.documentation_size"))
+                .with_boundaries(DOCUMENTATION_SIZE_BUCKETS.to_vec())
                 .with_unit("bytes")
                 .with_description("size of the generated documentation in bytes")
                 .build(),

src/metrics/macros.rs

@@ -24,6 +24,7 @@ macro_rules! metrics {
             pub(crate) cdn_queue_time: prometheus::HistogramVec,
             pub(crate) build_time: prometheus::Histogram,
             pub(crate) documentation_size: prometheus::Histogram,
+            pub(crate) response_time: prometheus::HistogramVec,
         }
         impl $name {
             $vis fn new() -> Result<Self, prometheus::Error> {
@@ -69,7 +70,7 @@ macro_rules! metrics {
                         "time spent building crates",
                     )
                     .namespace($namespace)
-                    .buckets($crate::metrics::build_time_histogram_buckets()),
+                    .buckets($crate::metrics::BUILD_TIME_HISTOGRAM_BUCKETS.to_vec()),
                 )?;
                 registry.register(Box::new(build_time.clone()))?;
 
@@ -83,13 +84,26 @@ macro_rules! metrics {
                 )?;
                 registry.register(Box::new(documentation_size.clone()))?;
 
+                let response_time = prometheus::HistogramVec::new(
+                    prometheus::HistogramOpts::new(
+                        "response_time",
+                        "The response times of various docs.rs routes",
+                    )
+                    .namespace($namespace)
+                    .buckets($crate::metrics::RESPONSE_TIME_HISTOGRAM_BUCKETS.to_vec())
+                    .variable_label("route"),
+                    &["route"],
+                )?;
+                registry.register(Box::new(response_time.clone()))?;
+
                 Ok(Self {
                     registry,
                     recently_accessed_releases: RecentlyAccessedReleases::new(),
                     cdn_invalidation_time,
                     cdn_queue_time,
                     build_time,
                     documentation_size,
+                    response_time,
                     $(
                         $(#[$meta])*
                         $metric,

src/metrics/mod.rs

@@ -59,31 +59,41 @@ pub const DOCUMENTATION_SIZE_BUCKETS: &[f64; 16] = &[
 ];
 
 /// the measured times of building crates will be put into these buckets
-pub fn build_time_histogram_buckets() -> Vec<f64> {
-    vec![
-        30.0,   // 0.5
-        60.0,   // 1
-        120.0,  // 2
-        180.0,  // 3
-        240.0,  // 4
-        300.0,  // 5
-        360.0,  // 6
-        420.0,  // 7
-        480.0,  // 8
-        540.0,  // 9
-        600.0,  // 10
-        660.0,  // 11
-        720.0,  // 12
-        780.0,  // 13
-        840.0,  // 14
-        900.0,  // 15
-        1200.0, // 20
-        1800.0, // 30
-        2400.0, // 40
-        3000.0, // 50
-        3600.0, // 60
-    ]
-}
+pub const BUILD_TIME_HISTOGRAM_BUCKETS: &[f64] = &[
+    30.0,   // 0.5
+    60.0,   // 1
+    120.0,  // 2
+    180.0,  // 3
+    240.0,  // 4
+    300.0,  // 5
+    360.0,  // 6
+    420.0,  // 7
+    480.0,  // 8
+    540.0,  // 9
+    600.0,  // 10
+    660.0,  // 11
+    720.0,  // 12
+    780.0,  // 13
+    840.0,  // 14
+    900.0,  // 15
+    1200.0, // 20
+    1800.0, // 30
+    2400.0, // 40
+    3000.0, // 50
+    3600.0, // 60
+];
+
+/// response time histogram buckets from the opentelemetry semantiv conventions
+/// https://opentelemetry.io/docs/specs/semconv/http/http-metrics/#metric-httpserverrequestduration
+///
+/// These are the default prometheus bucket sizes,
+/// https://docs.rs/prometheus/0.14.0/src/prometheus/histogram.rs.html#25-27
+/// tailored to broadly measure the response time (in seconds) of a network service.
+///
+/// Otel default buckets are not suited for that.
+pub const RESPONSE_TIME_HISTOGRAM_BUCKETS: &[f64] = &[
+    0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0,
+];
 
 metrics! {
     pub struct InstanceMetrics {
@@ -103,8 +113,6 @@ metrics! {
 
         /// The traffic of various docs.rs routes
         pub(crate) routes_visited: IntCounterVec["route"],
-        /// The response times of various docs.rs routes
-        pub(crate) response_time: HistogramVec["route"],
 
         /// Count of recently accessed crates
         pub(crate) recent_crates: IntGaugeVec["duration"],

src/web/metrics.rs

@@ -1,6 +1,8 @@
 use crate::{
-    AsyncBuildQueue, Config, InstanceMetrics, ServiceMetrics, db::Pool,
-    metrics::otel::AnyMeterProvider, web::error::AxumResult,
+    AsyncBuildQueue, Config, InstanceMetrics, ServiceMetrics,
+    db::Pool,
+    metrics::{RESPONSE_TIME_HISTOGRAM_BUCKETS, otel::AnyMeterProvider},
+    web::error::AxumResult,
 };
 use anyhow::{Context as _, Result};
 use axum::{
@@ -44,6 +46,7 @@ impl WebMetrics {
                 .build(),
             response_time: meter
                 .f64_histogram(format!("{PREFIX}.response_time"))
+                .with_boundaries(RESPONSE_TIME_HISTOGRAM_BUCKETS.to_vec())
                 .with_unit("s")
                 .build(),
         }