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Add missing buckets (aka boundaries) to OTEL histogram metrics #25

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Merged
regexident merged 1 commit into from
Mar 12, 2026
Merged

Add missing buckets (aka boundaries) to OTEL histogram metrics #25

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23 changes: 19 additions & 4 deletions src/telemetry.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -180,6 +180,7 @@ pub(crate) fn record_cache_hit(bytes: u64) {
static CACHE_HIT_BYTES_HISTOGRAM: LazyLock<Histogram<u64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.u64_histogram("s3_cache.hit_bytes_histogram")
.with_boundaries(OBJECT_SIZE_BUCKETS.to_vec())
.with_description("Distribution of object sizes on cache hits")
.build()
});
Expand Down Expand Up @@ -230,6 +231,7 @@ pub(crate) fn record_cache_miss(bytes: u64) {
static CACHE_MISS_BYTES_HISTOGRAM: LazyLock<Histogram<u64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.u64_histogram("s3_cache.miss_bytes_histogram")
.with_boundaries(OBJECT_SIZE_BUCKETS.to_vec())
.with_description("Distribution of object sizes on cache misses")
.build()
});
Expand Down Expand Up @@ -280,6 +282,7 @@ pub(crate) fn record_cache_eviction(bytes: u64) {
static CACHE_EVICTION_BYTES_HISTOGRAM: LazyLock<Histogram<u64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.u64_histogram("s3_cache.eviction_bytes_histogram")
.with_boundaries(OBJECT_SIZE_BUCKETS.to_vec())
.with_description("Distribution of object sizes on cache evictions")
.build()
});
Expand Down Expand Up @@ -331,6 +334,7 @@ pub(crate) fn record_cache_eviction_age(age_secs: f64) {
static CACHE_EVICTION_AGE_HISTOGRAM: LazyLock<Histogram<f64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.f64_histogram("s3_cache.eviction_age_histogram")
.with_boundaries(EVICTION_AGE_BUCKETS.to_vec())
.with_description("Age of objects (in seconds) at the time of eviction, capped at TTL")
.with_unit("s")
.build()
Expand Down Expand Up @@ -362,6 +366,7 @@ pub(crate) fn record_cache_oversized(bytes: u64) {
static CACHE_OVERSIZED_BYTES_HISTOGRAM: LazyLock<Histogram<u64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.u64_histogram("s3_cache.oversized_bytes_histogram")
.with_boundaries(OVERSIZED_OBJECT_SIZE_BUCKETS.to_vec())
.with_description("Distribution of object sizes that exceeded the max cacheable size")
.build()
});
Expand Down Expand Up @@ -415,6 +420,7 @@ pub(crate) fn record_unique_requested(bytes: u64) {
static CACHE_UNIQUE_REQUESTED_BYTES_HISTOGRAM: LazyLock<Histogram<u64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.u64_histogram("s3_cache.estimated_unique_bytes_histogram")
.with_boundaries(OBJECT_SIZE_BUCKETS.to_vec())
.with_description("Distribution of estimated unique object sizes")
.build()
});
Expand Down Expand Up @@ -623,9 +629,16 @@ pub(crate) struct RequestDuration {
}

pub(crate) fn record_request_duration(data: RequestDuration) {
static REQUEST_DURATION_BUCKETS: LazyLock<Vec<f64>> = LazyLock::new(|| {
vec![
1.0, 5.0, 10.0, 25.0, 50.0, 100.0, 250.0, 500.0, 1000.0, 2500.0, 5000.0, 10000.0,
]
});

static REQUEST_DURATION_MS: LazyLock<Histogram<f64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.f64_histogram("http.server.request.duration")
.with_boundaries(REQUEST_DURATION_BUCKETS.to_vec())
.with_description("Duration of the request in milliseconds")
.with_unit("ms")
.build()
Expand All @@ -637,9 +650,7 @@ pub(crate) fn record_request_duration(data: RequestDuration) {
"http_server_request_duration",
"Duration of get_object requests in milliseconds",
)
.buckets(vec![
1.0, 5.0, 10.0, 25.0, 50.0, 100.0, 250.0, 500.0, 1000.0, 2500.0, 5000.0, 10000.0,
]),
.buckets(REQUEST_DURATION_BUCKETS.to_vec()),
)
.unwrap();
PROMETHEUS_REGISTRY
Expand Down Expand Up @@ -682,9 +693,13 @@ pub(crate) struct ResponseBodySize {
}

pub(crate) fn record_response_body_size(data: ResponseBodySize) {
static RESPONSE_BODY_SIZE_BUCKETS: LazyLock<Vec<f64>> =
LazyLock::new(|| prometheus::exponential_buckets(1024.0, 4.0, 10).unwrap());

static RESPONSE_BODY_SIZE_BYTES: LazyLock<Histogram<f64>> = LazyLock::new(|| {
opentelemetry::global::meter(CARGO_CRATE_NAME)
.f64_histogram("http.server.response.body.size")
.with_boundaries(RESPONSE_BODY_SIZE_BUCKETS.to_vec())
.with_description("Size of the response body in bytes")
.with_unit("By")
.build()
Expand All @@ -696,7 +711,7 @@ pub(crate) fn record_response_body_size(data: ResponseBodySize) {
"http_server_response_body_size",
"Size of get_object response bodies in bytes",
)
.buckets(prometheus::exponential_buckets(1024.0, 4.0, 10).unwrap()),
.buckets(RESPONSE_BODY_SIZE_BUCKETS.to_vec()),
)
.unwrap();
PROMETHEUS_REGISTRY
Expand Down