Merge pull request #76 from frigus02/exp-histo

Support exporting ExponentialHistogram

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Set tags Cloud role and Cloud role instance also from resource attributes `k8s.{deployment,replicaset,statefulset,job,cronjob,daemonset,pod}.name`. This matches [the behavior of the JS exporter](https://github.com/Azure/azure-sdk-for-js/blob/c66cad23c4b803719db65cb48a453b0adc13307b/sdk/monitor/monitor-opentelemetry-exporter/src/utils/common.ts#L75-L138).
 - Remove option to configure temporality seletor (`with_temporality_selector`). Application Insights supports delta temporality only as defined in the [spec](https://github.com/open-telemetry/opentelemetry-specification/blob/58bfe48eabe887545198d66c43f44071b822373f/specification/metrics/sdk_exporters/otlp.md?plain=1#L46-L47).
+- Add support for `ExponentialHistogram` export.
 
 ## [0.31.0] - 2024-05-09
 

src/lib.rs

@@ -296,11 +296,12 @@ async fn main() {
 //! Metrics get reported to Application Insights as Metric Data. The [`Aggregation`] determines how
 //! the data is represented.
 //!
-//! | Aggregator | Data representation                                                  |
-//! | ---------- | -------------------------------------------------------------------- |
-//! | Histogram  | aggregation with sum, count, min, and max (buckets are not exported) |
-//! | Gauge      | one measurement                                                      |
-//! | Sum        | aggregation with only a value                                        |
+//! | Aggregator           | Data representation                                                  |
+//! | -------------------- | -------------------------------------------------------------------- |
+//! | Histogram            | aggregation with sum, count, min, and max (buckets are not exported) |
+//! | ExponentialHistogram | aggregation with sum, count, min, and max (buckets are not exported) |
+//! | Gauge                | one measurement                                                      |
+//! | Sum                  | aggregation with only a value                                        |
 //!
 //! [`Aggregation`]: https://docs.rs/opentelemetry/0.20.0/opentelemetry/sdk/metrics/data/trait.Aggregation.html
 #![doc(html_root_url = "https://docs.rs/opentelemetry-application-insights/0.31.0")]

src/metrics.rs

@@ -12,7 +12,7 @@ use opentelemetry::{
 use opentelemetry_http::HttpClient;
 use opentelemetry_sdk::{
     metrics::{
-        data::{Gauge, Histogram, Metric, ResourceMetrics, Sum, Temporality},
+        data::{ExponentialHistogram, Gauge, Histogram, Metric, ResourceMetrics, Sum, Temporality},
         exporter::PushMetricsExporter,
         reader::{AggregationSelector, TemporalitySelector},
         Aggregation, InstrumentKind,
@@ -152,6 +152,12 @@ fn map_metric(metric: &Metric) -> Vec<EnvelopeData> {
         map_histogram(metric, histogram)
     } else if let Some(histogram) = data.downcast_ref::<Histogram<f64>>() {
         map_histogram(metric, histogram)
+    } else if let Some(exp_histogram) = data.downcast_ref::<ExponentialHistogram<i64>>() {
+        map_exponential_histogram(metric, exp_histogram)
+    } else if let Some(exp_histogram) = data.downcast_ref::<ExponentialHistogram<u64>>() {
+        map_exponential_histogram(metric, exp_histogram)
+    } else if let Some(exp_histogram) = data.downcast_ref::<ExponentialHistogram<f64>>() {
+        map_exponential_histogram(metric, exp_histogram)
     } else if let Some(sum) = data.downcast_ref::<Sum<u64>>() {
         map_sum(metric, sum)
     } else if let Some(sum) = data.downcast_ref::<Sum<i64>>() {
@@ -208,6 +214,32 @@ fn map_histogram<T: ToF64Lossy>(metric: &Metric, histogram: &Histogram<T>) -> Ve
         .collect()
 }
 
+fn map_exponential_histogram<T: ToF64Lossy>(
+    metric: &Metric,
+    exp_histogram: &ExponentialHistogram<T>,
+) -> Vec<EnvelopeData> {
+    exp_histogram
+        .data_points
+        .iter()
+        .map(|data_point| {
+            let time = data_point.time;
+            let data = DataPoint {
+                ns: None,
+                name: metric.name.clone().into(),
+                kind: Some(DataPointType::Aggregation {
+                    count: Some(data_point.count.try_into().unwrap_or_default()),
+                    min: data_point.min.as_ref().map(ToF64Lossy::to_f64_lossy),
+                    max: data_point.max.as_ref().map(ToF64Lossy::to_f64_lossy),
+                    std_dev: None,
+                }),
+                value: data_point.sum.to_f64_lossy(),
+            };
+            let attrs = data_point.attributes.to_owned();
+            EnvelopeData { time, data, attrs }
+        })
+        .collect()
+}
+
 fn map_sum<T: ToF64Lossy>(metric: &Metric, sum: &Sum<T>) -> Vec<EnvelopeData> {
     sum.data_points
         .iter()