fix: Avoid exposing HistogramBuckets and bounds (#2969)

Author: cijothomas

opentelemetry-proto/src/transform/metrics.rs

@@ -215,8 +215,8 @@ pub mod tonic {
                         time_unix_nano: to_nanos(hist.time),
                         count: dp.count,
                         sum: Some(dp.sum.into_f64()),
-                        bucket_counts: dp.bucket_counts.clone(),
-                        explicit_bounds: dp.bounds.clone(),
+                        bucket_counts: dp.bucket_counts().collect(),
+                        explicit_bounds: dp.bounds().collect(),
                         exemplars: dp.exemplars().map(Into::into).collect(),
                         flags: TonicDataPointFlags::default() as u32,
                         min: dp.min.map(Numeric::into_f64),

opentelemetry-sdk/CHANGELOG.md

@@ -61,6 +61,9 @@ also modified to suppress telemetry before invoking exporters.
   - `Exemplar` no longer exposes `filtered_attributes` field, but instead
      offers `filtered_attributes()` method that returns an iterator over
      the same.
+  - `HistogramDataPoint` no longer exposes `bounds` and `bucket_counts`, but
+    instead offers `bounds()` and `bucket_counts()` methods that returns an
+    iterator over the same.
 
 ## 0.29.0
 

opentelemetry-sdk/src/metrics/data/mod.rs

@@ -148,7 +148,7 @@ impl<T> GaugeDataPoint<T> {
         self.attributes.iter()
     }
 
-    /// Returns an iterator over the exemplars in [GaugeDataPoint].
+    /// Returns an iterator over the [Exemplar]s in [GaugeDataPoint].
     pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
         self.exemplars.iter()
     }
@@ -190,7 +190,7 @@ impl<T> SumDataPoint<T> {
         self.attributes.iter()
     }
 
-    /// Returns an iterator over the exemplars in [SumDataPoint].
+    /// Returns an iterator over the [Exemplar]s in [SumDataPoint].
     pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
         self.exemplars.iter()
     }
@@ -250,9 +250,9 @@ pub struct HistogramDataPoint<T> {
     /// The upper bounds of the buckets of the histogram.
     ///
     /// Because the last boundary is +infinity this one is implied.
-    pub bounds: Vec<f64>,
+    pub(crate) bounds: Vec<f64>,
     /// The count of each of the buckets.
-    pub bucket_counts: Vec<u64>,
+    pub(crate) bucket_counts: Vec<u64>,
 
     /// The minimum value recorded.
     pub min: Option<T>,
@@ -275,6 +275,16 @@ impl<T> HistogramDataPoint<T> {
     pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
         self.exemplars.iter()
     }
+
+    /// Returns an iterator over the bucket boundaries in [HistogramDataPoint].
+    pub fn bounds(&self) -> impl Iterator<Item = f64> + '_ {
+        self.bounds.iter().copied()
+    }
+
+    /// Returns an iterator over the bucket counts in [HistogramDataPoint].
+    pub fn bucket_counts(&self) -> impl Iterator<Item = u64> + '_ {
+        self.bucket_counts.iter().copied()
+    }
 }
 
 /// The histogram of all measurements of values from an instrument.

opentelemetry-stdout/src/metrics/exporter.rs

@@ -242,19 +242,28 @@ fn print_hist_data_points<'a, T: Debug + 'a>(
             println!("\t\t\t\t ->  {}: {}", kv.key, kv.value.as_str());
         }
 
-        if !data_point.bucket_counts.is_empty() {
-            println!("\t\t\tBuckets");
-            let mut lower_bound = f64::NEG_INFINITY;
-            for (i, &upper_bound) in data_point.bounds.iter().enumerate() {
-                let count = data_point.bucket_counts.get(i).unwrap_or(&0);
-                println!("\t\t\t\t {} to {} : {}", lower_bound, upper_bound, count);
-                lower_bound = upper_bound;
+        let mut lower_bound = f64::NEG_INFINITY;
+        let bounds_iter = data_point.bounds();
+        let mut bucket_counts_iter = data_point.bucket_counts();
+        let mut header_printed = false;
+
+        // Process all the regular buckets
+        for upper_bound in bounds_iter {
+            // Print header only once before the first item
+            if !header_printed {
+                println!("\t\t\tBuckets");
+                header_printed = true;
             }
 
-            let last_count = data_point
-                .bucket_counts
-                .get(data_point.bounds.len())
-                .unwrap_or(&0);
+            // Get the count for this bucket, or 0 if not available
+            let count = bucket_counts_iter.next().unwrap_or(0);
+            println!("\t\t\t\t {} to {} : {}", lower_bound, upper_bound, count);
+            lower_bound = upper_bound;
+        }
+
+        // Handle the final +Infinity bucket if we processed any buckets
+        if header_printed {
+            let last_count = bucket_counts_iter.next().unwrap_or(0);
             println!("\t\t\t\t{} to +Infinity : {}", lower_bound, last_count);
         }
     }