fix: MetricExporters use getter methods instead of direct access (#2973)

Co-authored-by: Lalit Kumar Bhasin <[email protected]>

Author: cijothomas

opentelemetry-proto/src/transform/metrics.rs

@@ -114,9 +114,13 @@ pub mod tonic {
         fn from(rm: &ResourceMetrics) -> Self {
             ExportMetricsServiceRequest {
                 resource_metrics: vec![TonicResourceMetrics {
-                    resource: Some((&rm.resource).into()),
+                    resource: Some((rm.resource()).into()),
                     scope_metrics: rm.scope_metrics().map(Into::into).collect(),
-                    schema_url: rm.resource.schema_url().map(Into::into).unwrap_or_default(),
+                    schema_url: rm
+                        .resource()
+                        .schema_url()
+                        .map(Into::into)
+                        .unwrap_or_default(),
                 }],
             }
         }
@@ -135,10 +139,10 @@ pub mod tonic {
     impl From<&SdkScopeMetrics> for TonicScopeMetrics {
         fn from(sm: &SdkScopeMetrics) -> Self {
             TonicScopeMetrics {
-                scope: Some((&sm.scope, None).into()),
+                scope: Some((sm.scope(), None).into()),
                 metrics: sm.metrics().map(Into::into).collect(),
                 schema_url: sm
-                    .scope
+                    .scope()
                     .schema_url()
                     .map(ToOwned::to_owned)
                     .unwrap_or_default(),
@@ -149,11 +153,11 @@ pub mod tonic {
     impl From<&SdkMetric> for TonicMetric {
         fn from(metric: &SdkMetric) -> Self {
             TonicMetric {
-                name: metric.name.to_string(),
-                description: metric.description.to_string(),
-                unit: metric.unit.to_string(),
+                name: metric.name().to_string(),
+                description: metric.description().to_string(),
+                unit: metric.unit().to_string(),
                 metadata: vec![], // internal and currently unused
-                data: Some(match &metric.data {
+                data: Some(match metric.data() {
                     AggregatedMetrics::F64(data) => data.into(),
                     AggregatedMetrics::U64(data) => data.into(),
                     AggregatedMetrics::I64(data) => data.into(),

opentelemetry-sdk/CHANGELOG.md

@@ -65,6 +65,12 @@ also modified to suppress telemetry before invoking exporters.
   - `HistogramDataPoint` no longer exposes `bounds` and `bucket_counts`, but
     instead offers `bounds()` and `bucket_counts()` methods that returns an
     iterator over the same.
+  - `Metric` no longer exposes `name`, `description`, `unit`, `data` fields, but
+    instead offers `name()`, `description()`, `unit()`, and `data()` accessor methods.
+  - `ResourceMetrics` no longer exposes `resource` field, but instead offers
+    a `resource()` accessor method.
+  - `ScopeMetrics` no longer exposes `scope` field, but instead offers
+    a `scope()` accessor method.
 
 ## 0.29.0
 

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

@@ -12,7 +12,7 @@ use super::Temporality;
 #[derive(Debug)]
 pub struct ResourceMetrics {
     /// The entity that collected the metrics.
-    pub resource: Resource,
+    pub(crate) resource: Resource,
     /// The collection of metrics with unique [InstrumentationScope]s.
     pub(crate) scope_metrics: Vec<ScopeMetrics>,
 }
@@ -27,6 +27,11 @@ impl Default for ResourceMetrics {
 }
 
 impl ResourceMetrics {
+    /// Returns a reference to the [Resource] in [ResourceMetrics].
+    pub fn resource(&self) -> &Resource {
+        &self.resource
+    }
+
     /// Returns an iterator over the [ScopeMetrics] in [ResourceMetrics].
     pub fn scope_metrics(&self) -> impl Iterator<Item = &ScopeMetrics> {
         self.scope_metrics.iter()
@@ -37,12 +42,17 @@ impl ResourceMetrics {
 #[derive(Default, Debug)]
 pub struct ScopeMetrics {
     /// The [InstrumentationScope] that the meter was created with.
-    pub scope: InstrumentationScope,
+    pub(crate) scope: InstrumentationScope,
     /// The list of aggregations created by the meter.
     pub(crate) metrics: Vec<Metric>,
 }
 
 impl ScopeMetrics {
+    /// Returns a reference to the [InstrumentationScope] in [ScopeMetrics].
+    pub fn scope(&self) -> &InstrumentationScope {
+        &self.scope
+    }
+
     /// Returns an iterator over the [Metric]s in [ScopeMetrics].
     pub fn metrics(&self) -> impl Iterator<Item = &Metric> {
         self.metrics.iter()
@@ -55,13 +65,35 @@ impl ScopeMetrics {
 #[derive(Debug)]
 pub struct Metric {
     /// The name of the instrument that created this data.
-    pub name: Cow<'static, str>,
+    pub(crate) name: Cow<'static, str>,
     /// The description of the instrument, which can be used in documentation.
-    pub description: Cow<'static, str>,
+    pub(crate) description: Cow<'static, str>,
     /// The unit in which the instrument reports.
-    pub unit: Cow<'static, str>,
+    pub(crate) unit: Cow<'static, str>,
     /// The aggregated data from an instrument.
-    pub data: AggregatedMetrics,
+    pub(crate) data: AggregatedMetrics,
+}
+
+impl Metric {
+    /// Returns the name of the instrument that created this data.
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
+    /// Returns the description of the instrument.
+    pub fn description(&self) -> &str {
+        &self.description
+    }
+
+    /// Returns the unit in which the instrument reports.
+    pub fn unit(&self) -> &str {
+        &self.unit
+    }
+
+    /// Returns the aggregated data from the instrument.
+    pub fn data(&self) -> &AggregatedMetrics {
+        &self.data
+    }
 }
 
 /// Aggregated metrics data from an instrument

opentelemetry-stdout/src/metrics/exporter.rs

@@ -48,11 +48,11 @@ impl PushMetricExporter for MetricExporter {
         } else {
             println!("Metrics");
             println!("Resource");
-            if let Some(schema_url) = metrics.resource.schema_url() {
+            if let Some(schema_url) = metrics.resource().schema_url() {
                 println!("\tResource SchemaUrl: {:?}", schema_url);
             }
 
-            metrics.resource.iter().for_each(|(k, v)| {
+            metrics.resource().iter().for_each(|(k, v)| {
                 println!("\t ->  {}={:?}", k, v);
             });
             print_metrics(metrics.scope_metrics());
@@ -82,29 +82,26 @@ impl PushMetricExporter for MetricExporter {
 fn print_metrics<'a>(metrics: impl Iterator<Item = &'a ScopeMetrics>) {
     for (i, metric) in metrics.enumerate() {
         println!("\tInstrumentation Scope #{}", i);
-        println!("\t\tName         : {}", &metric.scope.name());
-        if let Some(version) = &metric.scope.version() {
+        let scope = metric.scope();
+        println!("\t\tName         : {}", scope.name());
+        if let Some(version) = scope.version() {
             println!("\t\tVersion  : {:?}", version);
         }
-        if let Some(schema_url) = &metric.scope.schema_url() {
+        if let Some(schema_url) = scope.schema_url() {
             println!("\t\tSchemaUrl: {:?}", schema_url);
         }
-        metric
-            .scope
-            .attributes()
-            .enumerate()
-            .for_each(|(index, kv)| {
-                if index == 0 {
-                    println!("\t\tScope Attributes:");
-                }
-                println!("\t\t\t ->  {}: {}", kv.key, kv.value);
-            });
+        scope.attributes().enumerate().for_each(|(index, kv)| {
+            if index == 0 {
+                println!("\t\tScope Attributes:");
+            }
+            println!("\t\t\t ->  {}: {}", kv.key, kv.value);
+        });
 
         metric.metrics().enumerate().for_each(|(i, metric)| {
             println!("Metric #{}", i);
-            println!("\t\tName         : {}", &metric.name);
-            println!("\t\tDescription  : {}", &metric.description);
-            println!("\t\tUnit         : {}", &metric.unit);
+            println!("\t\tName         : {}", metric.name());
+            println!("\t\tDescription  : {}", metric.description());
+            println!("\t\tUnit         : {}", metric.unit());
 
             fn print_info<T>(data: &MetricData<T>)
             where
@@ -129,7 +126,7 @@ fn print_metrics<'a>(metrics: impl Iterator<Item = &'a ScopeMetrics>) {
                     }
                 }
             }
-            match &metric.data {
+            match metric.data() {
                 AggregatedMetrics::F64(data) => print_info(data),
                 AggregatedMetrics::U64(data) => print_info(data),
                 AggregatedMetrics::I64(data) => print_info(data),