fix: Avoid exposing implementation detail in public API for PushMetricExporter (#2968)

Author: cijothomas

opentelemetry-proto/src/transform/metrics.rs

@@ -208,17 +208,16 @@ pub mod tonic {
         fn from(hist: &SdkHistogram<T>) -> Self {
             TonicHistogram {
                 data_points: hist
-                    .data_points
-                    .iter()
+                    .data_points()
                     .map(|dp| TonicHistogramDataPoint {
-                        attributes: dp.attributes.iter().map(Into::into).collect(),
+                        attributes: dp.attributes().map(Into::into).collect(),
                         start_time_unix_nano: to_nanos(hist.start_time),
                         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(),
-                        exemplars: dp.exemplars.iter().map(Into::into).collect(),
+                        exemplars: dp.exemplars().map(Into::into).collect(),
                         flags: TonicDataPointFlags::default() as u32,
                         min: dp.min.map(Numeric::into_f64),
                         max: dp.max.map(Numeric::into_f64),
@@ -236,10 +235,9 @@ pub mod tonic {
         fn from(hist: &SdkExponentialHistogram<T>) -> Self {
             TonicExponentialHistogram {
                 data_points: hist
-                    .data_points
-                    .iter()
+                    .data_points()
                     .map(|dp| TonicExponentialHistogramDataPoint {
-                        attributes: dp.attributes.iter().map(Into::into).collect(),
+                        attributes: dp.attributes().map(Into::into).collect(),
                         start_time_unix_nano: to_nanos(hist.start_time),
                         time_unix_nano: to_nanos(hist.time),
                         count: dp.count as u64,
@@ -255,7 +253,7 @@ pub mod tonic {
                             bucket_counts: dp.negative_bucket.counts.clone(),
                         }),
                         flags: TonicDataPointFlags::default() as u32,
-                        exemplars: dp.exemplars.iter().map(Into::into).collect(),
+                        exemplars: dp.exemplars().map(Into::into).collect(),
                         min: dp.min.map(Numeric::into_f64),
                         max: dp.max.map(Numeric::into_f64),
                         zero_threshold: dp.zero_threshold,
@@ -275,10 +273,10 @@ pub mod tonic {
                 data_points: sum
                     .data_points()
                     .map(|dp| TonicNumberDataPoint {
-                        attributes: dp.attributes.iter().map(Into::into).collect(),
+                        attributes: dp.attributes().map(Into::into).collect(),
                         start_time_unix_nano: to_nanos(sum.start_time),
                         time_unix_nano: to_nanos(sum.time),
-                        exemplars: dp.exemplars.iter().map(Into::into).collect(),
+                        exemplars: dp.exemplars().map(Into::into).collect(),
                         flags: TonicDataPointFlags::default() as u32,
                         value: Some(dp.value.into()),
                     })
@@ -296,13 +294,12 @@ pub mod tonic {
         fn from(gauge: &SdkGauge<T>) -> Self {
             TonicGauge {
                 data_points: gauge
-                    .data_points
-                    .iter()
+                    .data_points()
                     .map(|dp| TonicNumberDataPoint {
-                        attributes: dp.attributes.iter().map(Into::into).collect(),
+                        attributes: dp.attributes().map(Into::into).collect(),
                         start_time_unix_nano: gauge.start_time.map(to_nanos).unwrap_or_default(),
                         time_unix_nano: to_nanos(gauge.time),
-                        exemplars: dp.exemplars.iter().map(Into::into).collect(),
+                        exemplars: dp.exemplars().map(Into::into).collect(),
                         flags: TonicDataPointFlags::default() as u32,
                         value: Some(dp.value.into()),
                     })
@@ -318,8 +315,7 @@ pub mod tonic {
         fn from(ex: &SdkExemplar<T>) -> Self {
             TonicExemplar {
                 filtered_attributes: ex
-                    .filtered_attributes
-                    .iter()
+                    .filtered_attributes()
                     .map(|kv| (&kv.key, &kv.value).into())
                     .collect(),
                 time_unix_nano: to_nanos(ex.time),

opentelemetry-sdk/CHANGELOG.md

@@ -47,6 +47,20 @@ also modified to suppress telemetry before invoking exporters.
 - *Breaking* change, affecting custom `PushMetricExporter` authors:
   - The `export` method on `PushMetricExporter` now accepts `&ResourceMetrics`
     instead of `&mut ResourceMetrics`.
+  - `ResourceMetrics` no longer exposes `scope_metrics` field, but instead
+    offers `scope_metrics()` method that returns an iterator over the same.
+  - `ScopeMetrics` no longer exposes `metrics` field, but instead offers
+    `metrics()` method that returns an iterator over the same.
+  - `Sum`, `Gauge`, `Histogram` & `ExponentialHistogram` no longer exposes
+    `data_points` field, but instead offers `data_points()` method that returns
+    an iterator over the same.
+  - `SumDataPoint`, `GaugeDataPoint`, `HistogramDataPoint` &
+    `ExponentialHistogramDataPoint` no longer exposes `attributes`, `exemplars`
+    field, but instead offers `attributes()`, and `exemplars()` method that
+    returns an iterator over the same.
+  - `Exemplar` no longer exposes `filtered_attributes` field, but instead
+     offers `filtered_attributes()` method that returns an iterator over
+     the same.
 
 ## 0.29.0
 

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

@@ -135,34 +135,65 @@ impl<T> From<ExponentialHistogram<T>> for MetricData<T> {
 pub struct GaugeDataPoint<T> {
     /// Attributes is the set of key value pairs that uniquely identify the
     /// time series.
-    pub attributes: Vec<KeyValue>,
+    pub(crate) attributes: Vec<KeyValue>,
     /// The value of this data point.
     pub value: T,
     /// The sampled [Exemplar]s collected during the time series.
-    pub exemplars: Vec<Exemplar<T>>,
+    pub(crate) exemplars: Vec<Exemplar<T>>,
+}
+
+impl<T> GaugeDataPoint<T> {
+    /// Returns an iterator over the attributes in [GaugeDataPoint].
+    pub fn attributes(&self) -> impl Iterator<Item = &KeyValue> {
+        self.attributes.iter()
+    }
+
+    /// Returns an iterator over the exemplars in [GaugeDataPoint].
+    pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
+        self.exemplars.iter()
+    }
 }
 
 /// A measurement of the current value of an instrument.
 #[derive(Debug, Clone)]
 pub struct Gauge<T> {
     /// Represents individual aggregated measurements with unique attributes.
-    pub data_points: Vec<GaugeDataPoint<T>>,
+    pub(crate) data_points: Vec<GaugeDataPoint<T>>,
     /// The time when the time series was started.
     pub start_time: Option<SystemTime>,
     /// The time when the time series was recorded.
     pub time: SystemTime,
 }
 
+impl<T> Gauge<T> {
+    /// Returns an iterator over the [GaugeDataPoint]s in [Gauge].
+    pub fn data_points(&self) -> impl Iterator<Item = &GaugeDataPoint<T>> {
+        self.data_points.iter()
+    }
+}
+
 /// DataPoint is a single data point in a time series.
 #[derive(Debug, Clone, PartialEq)]
 pub struct SumDataPoint<T> {
     /// Attributes is the set of key value pairs that uniquely identify the
     /// time series.
-    pub attributes: Vec<KeyValue>,
+    pub(crate) attributes: Vec<KeyValue>,
     /// The value of this data point.
     pub value: T,
     /// The sampled [Exemplar]s collected during the time series.
-    pub exemplars: Vec<Exemplar<T>>,
+    pub(crate) exemplars: Vec<Exemplar<T>>,
+}
+
+impl<T> SumDataPoint<T> {
+    /// Returns an iterator over the attributes in [SumDataPoint].
+    pub fn attributes(&self) -> impl Iterator<Item = &KeyValue> {
+        self.attributes.iter()
+    }
+
+    /// Returns an iterator over the exemplars in [SumDataPoint].
+    pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
+        self.exemplars.iter()
+    }
 }
 
 /// Represents the sum of all measurements of values from an instrument.
@@ -192,7 +223,7 @@ impl<T> Sum<T> {
 #[derive(Debug, Clone)]
 pub struct Histogram<T> {
     /// Individual aggregated measurements with unique attributes.
-    pub data_points: Vec<HistogramDataPoint<T>>,
+    pub(crate) data_points: Vec<HistogramDataPoint<T>>,
     /// The time when the time series was started.
     pub start_time: SystemTime,
     /// The time when the time series was recorded.
@@ -202,11 +233,18 @@ pub struct Histogram<T> {
     pub temporality: Temporality,
 }
 
+impl<T> Histogram<T> {
+    /// Returns an iterator over the [HistogramDataPoint]s in [Histogram].
+    pub fn data_points(&self) -> impl Iterator<Item = &HistogramDataPoint<T>> {
+        self.data_points.iter()
+    }
+}
+
 /// A single histogram data point in a time series.
 #[derive(Debug, Clone, PartialEq)]
 pub struct HistogramDataPoint<T> {
     /// The set of key value pairs that uniquely identify the time series.
-    pub attributes: Vec<KeyValue>,
+    pub(crate) attributes: Vec<KeyValue>,
     /// The number of updates this histogram has been calculated with.
     pub count: u64,
     /// The upper bounds of the buckets of the histogram.
@@ -224,14 +262,26 @@ pub struct HistogramDataPoint<T> {
     pub sum: T,
 
     /// The sampled [Exemplar]s collected during the time series.
-    pub exemplars: Vec<Exemplar<T>>,
+    pub(crate) exemplars: Vec<Exemplar<T>>,
+}
+
+impl<T> HistogramDataPoint<T> {
+    /// Returns an iterator over the attributes in [HistogramDataPoint].
+    pub fn attributes(&self) -> impl Iterator<Item = &KeyValue> {
+        self.attributes.iter()
+    }
+
+    /// Returns an iterator over the exemplars in [HistogramDataPoint].
+    pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
+        self.exemplars.iter()
+    }
 }
 
 /// The histogram of all measurements of values from an instrument.
 #[derive(Debug, Clone)]
 pub struct ExponentialHistogram<T> {
     /// The individual aggregated measurements with unique attributes.
-    pub data_points: Vec<ExponentialHistogramDataPoint<T>>,
+    pub(crate) data_points: Vec<ExponentialHistogramDataPoint<T>>,
     /// When the time series was started.
     pub start_time: SystemTime,
     /// The time when the time series was recorded.
@@ -241,11 +291,18 @@ pub struct ExponentialHistogram<T> {
     pub temporality: Temporality,
 }
 
+impl<T> ExponentialHistogram<T> {
+    /// Returns an iterator over the [ExponentialHistogramDataPoint]s in [ExponentialHistogram].
+    pub fn data_points(&self) -> impl Iterator<Item = &ExponentialHistogramDataPoint<T>> {
+        self.data_points.iter()
+    }
+}
+
 /// A single exponential histogram data point in a time series.
 #[derive(Debug, Clone, PartialEq)]
 pub struct ExponentialHistogramDataPoint<T> {
     /// The set of key value pairs that uniquely identify the time series.
-    pub attributes: Vec<KeyValue>,
+    pub(crate) attributes: Vec<KeyValue>,
 
     /// The number of updates this histogram has been calculated with.
     pub count: usize,
@@ -283,7 +340,19 @@ pub struct ExponentialHistogramDataPoint<T> {
     pub zero_threshold: f64,
 
     /// The sampled exemplars collected during the time series.
-    pub exemplars: Vec<Exemplar<T>>,
+    pub(crate) exemplars: Vec<Exemplar<T>>,
+}
+
+impl<T> ExponentialHistogramDataPoint<T> {
+    /// Returns an iterator over the attributes in [ExponentialHistogramDataPoint].
+    pub fn attributes(&self) -> impl Iterator<Item = &KeyValue> {
+        self.attributes.iter()
+    }
+
+    /// Returns an iterator over the exemplars in [ExponentialHistogramDataPoint].
+    pub fn exemplars(&self) -> impl Iterator<Item = &Exemplar<T>> {
+        self.exemplars.iter()
+    }
 }
 
 /// A set of bucket counts, encoded in a contiguous array of counts.
@@ -304,7 +373,7 @@ pub struct ExponentialBucket {
 pub struct Exemplar<T> {
     /// The attributes recorded with the measurement but filtered out of the
     /// time series' aggregated data.
-    pub filtered_attributes: Vec<KeyValue>,
+    pub(crate) filtered_attributes: Vec<KeyValue>,
     /// The time when the measurement was recorded.
     pub time: SystemTime,
     /// The measured value.
@@ -319,6 +388,13 @@ pub struct Exemplar<T> {
     pub trace_id: [u8; 16],
 }
 
+impl<T> Exemplar<T> {
+    /// Returns an iterator over the filtered attributes in [Exemplar].
+    pub fn filtered_attributes(&self) -> impl Iterator<Item = &KeyValue> {
+        self.filtered_attributes.iter()
+    }
+}
+
 #[cfg(test)]
 mod tests {
 

opentelemetry-stdout/src/metrics/exporter.rs

@@ -125,6 +125,7 @@ fn print_metrics<'a>(metrics: impl Iterator<Item = &'a ScopeMetrics>) {
                     }
                     MetricData::ExponentialHistogram(_) => {
                         println!("\t\tType         : Exponential Histogram");
+                        // TODO: add support for ExponentialHistogram
                     }
                 }
             }
@@ -172,7 +173,7 @@ fn print_gauge<T: Debug>(gauge: &Gauge<T>) {
         "\t\tEndTime      : {}",
         datetime.format("%Y-%m-%d %H:%M:%S%.6f")
     );
-    print_gauge_data_points(&gauge.data_points);
+    print_gauge_data_points(gauge.data_points());
 }
 
 fn print_histogram<T: Debug>(histogram: &Histogram<T>) {
@@ -192,7 +193,7 @@ fn print_histogram<T: Debug>(histogram: &Histogram<T>) {
         datetime.format("%Y-%m-%d %H:%M:%S%.6f")
     );
     println!("\t\tHistogram DataPoints");
-    print_hist_data_points(&histogram.data_points);
+    print_hist_data_points(histogram.data_points());
 }
 
 fn print_sum_data_points<'a, T: Debug + 'a>(
@@ -202,25 +203,29 @@ fn print_sum_data_points<'a, T: Debug + 'a>(
         println!("\t\tDataPoint #{}", i);
         println!("\t\t\tValue        : {:#?}", data_point.value);
         println!("\t\t\tAttributes   :");
-        for kv in data_point.attributes.iter() {
+        for kv in data_point.attributes() {
             println!("\t\t\t\t ->  {}: {}", kv.key, kv.value.as_str());
         }
     }
 }
 
-fn print_gauge_data_points<T: Debug>(data_points: &[GaugeDataPoint<T>]) {
-    for (i, data_point) in data_points.iter().enumerate() {
+fn print_gauge_data_points<'a, T: Debug + 'a>(
+    data_points: impl Iterator<Item = &'a GaugeDataPoint<T>>,
+) {
+    for (i, data_point) in data_points.enumerate() {
         println!("\t\tDataPoint #{}", i);
         println!("\t\t\tValue        : {:#?}", data_point.value);
         println!("\t\t\tAttributes   :");
-        for kv in data_point.attributes.iter() {
+        for kv in data_point.attributes() {
             println!("\t\t\t\t ->  {}: {}", kv.key, kv.value.as_str());
         }
     }
 }
 
-fn print_hist_data_points<T: Debug>(data_points: &[HistogramDataPoint<T>]) {
-    for (i, data_point) in data_points.iter().enumerate() {
+fn print_hist_data_points<'a, T: Debug + 'a>(
+    data_points: impl Iterator<Item = &'a HistogramDataPoint<T>>,
+) {
+    for (i, data_point) in data_points.enumerate() {
         println!("\t\tDataPoint #{}", i);
         println!("\t\t\tCount        : {}", data_point.count);
         println!("\t\t\tSum          : {:?}", data_point.sum);
@@ -233,7 +238,7 @@ fn print_hist_data_points<T: Debug>(data_points: &[HistogramDataPoint<T>]) {
         }
 
         println!("\t\t\tAttributes   :");
-        for kv in data_point.attributes.iter() {
+        for kv in data_point.attributes() {
             println!("\t\t\t\t ->  {}: {}", kv.key, kv.value.as_str());
         }