example: add temporality selector option to metrics-basic (#2217)

Co-authored-by: Cijo Thomas <cijo.thomas@gmail.com>

examples/metrics-advanced/src/main.rs

@@ -1,9 +1,8 @@
 use opentelemetry::global;
 use opentelemetry::Key;
 use opentelemetry::KeyValue;
-use opentelemetry_sdk::metrics::reader::DeltaTemporalitySelector;
 use opentelemetry_sdk::metrics::{
-    Aggregation, Instrument, PeriodicReader, SdkMeterProvider, Stream,
+    data::Temporality, Aggregation, Instrument, PeriodicReader, SdkMeterProvider, Stream,
 };
 use opentelemetry_sdk::{runtime, Resource};
 use std::error::Error;
@@ -47,7 +46,7 @@ fn init_meter_provider() -> opentelemetry_sdk::metrics::SdkMeterProvider {
 
     // Build exporter using Delta Temporality.
     let exporter = opentelemetry_stdout::MetricsExporterBuilder::default()
-        .with_temporality_selector(DeltaTemporalitySelector::new())
+        .with_temporality(Temporality::Delta)
         .build();
 
     let reader = PeriodicReader::builder(exporter, runtime::Tokio).build();

examples/metrics-basic/src/main.rs

@@ -6,7 +6,10 @@ use std::error::Error;
 use std::vec;
 
 fn init_meter_provider() -> opentelemetry_sdk::metrics::SdkMeterProvider {
-    let exporter = opentelemetry_stdout::MetricsExporterBuilder::default().build();
+    let exporter = opentelemetry_stdout::MetricsExporterBuilder::default()
+        // Build exporter using Delta Temporality (Defaults to Temporality::Cumulative)
+        // .with_temporality(data::Temporality::Delta)
+        .build();
     let reader = PeriodicReader::builder(exporter, runtime::Tokio).build();
     let provider = SdkMeterProvider::builder()
         .with_reader(reader)

opentelemetry-otlp/CHANGELOG.md

@@ -10,6 +10,16 @@ Released 2024-Sep-30
 - Update `opentelemetry-http` dependency version to 0.26
 - Update `opentelemetry-proto` dependency version to 0.26
 - Bump MSRV to 1.71.1 [2140](https://github.com/open-telemetry/opentelemetry-rust/pull/2140)
+- **BREAKING**: [#2217](https://github.com/open-telemetry/opentelemetry-rust/pull/2217)
+  - **Replaced**: The `MetricsExporterBuilder` interface is modified from `with_temporality_selector` to `with_temporality` example can be seen below:
+    Previous Signature:
+    ```rust
+    MetricsExporterBuilder::default().with_temporality_selector(DeltaTemporalitySelector::new())
+    ```
+    Updated Signature:
+    ```rust
+    MetricsExporterBuilder::default().with_temporality(Temporality::Delta)
+    ```
 
 ## v0.25.0
 

opentelemetry-otlp/src/exporter/http/mod.rs

@@ -17,8 +17,6 @@ use opentelemetry_proto::transform::trace::tonic::group_spans_by_resource_and_sc
 use opentelemetry_sdk::export::logs::LogBatch;
 #[cfg(feature = "trace")]
 use opentelemetry_sdk::export::trace::SpanData;
-#[cfg(feature = "metrics")]
-use opentelemetry_sdk::metrics::data::ResourceMetrics;
 use prost::Message;
 use std::collections::HashMap;
 use std::env;
@@ -77,9 +75,7 @@ impl Default for HttpConfig {
 ///
 /// ```
 /// # #[cfg(feature="metrics")]
-/// use opentelemetry_sdk::metrics::reader::{
-///     DefaultTemporalitySelector,
-/// };
+/// use opentelemetry_sdk::metrics::data::Temporality;
 ///
 /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
 /// // Create a span exporter you can use to when configuring tracer providers
@@ -91,7 +87,7 @@ impl Default for HttpConfig {
 /// let metrics_exporter = opentelemetry_otlp::new_exporter()
 ///     .http()
 ///     .build_metrics_exporter(
-///         Box::new(DefaultTemporalitySelector::new()),
+///         Temporality::default(),
 ///     )?;
 ///
 /// // Create a log exporter you can use when configuring logger providers
@@ -251,7 +247,7 @@ impl HttpExporterBuilder {
     #[cfg(feature = "metrics")]
     pub fn build_metrics_exporter(
         mut self,
-        temporality_selector: Box<dyn opentelemetry_sdk::metrics::reader::TemporalitySelector>,
+        temporality: opentelemetry_sdk::metrics::data::Temporality,
     ) -> opentelemetry::metrics::Result<crate::MetricsExporter> {
         use crate::{
             OTEL_EXPORTER_OTLP_METRICS_ENDPOINT, OTEL_EXPORTER_OTLP_METRICS_HEADERS,
@@ -265,7 +261,7 @@ impl HttpExporterBuilder {
             OTEL_EXPORTER_OTLP_METRICS_HEADERS,
         )?;
 
-        Ok(crate::MetricsExporter::new(client, temporality_selector))
+        Ok(crate::MetricsExporter::new(client, temporality))
     }
 }
 
@@ -341,7 +337,7 @@ impl OtlpHttpClient {
     #[cfg(feature = "metrics")]
     fn build_metrics_export_body(
         &self,
-        metrics: &mut ResourceMetrics,
+        metrics: &mut opentelemetry_sdk::metrics::data::ResourceMetrics,
     ) -> opentelemetry::metrics::Result<(Vec<u8>, &'static str)> {
         use opentelemetry_proto::tonic::collector::metrics::v1::ExportMetricsServiceRequest;
 

opentelemetry-otlp/src/exporter/tonic/mod.rs

@@ -96,9 +96,7 @@ fn resolve_compression(
 ///
 /// ```no_run
 /// # #[cfg(feature="metrics")]
-/// use opentelemetry_sdk::metrics::reader::{
-///     DefaultTemporalitySelector,
-/// };
+/// use opentelemetry_sdk::metrics::data::Temporality;
 ///
 /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
 /// // Create a span exporter you can use to when configuring tracer providers
@@ -110,7 +108,7 @@ fn resolve_compression(
 /// let metrics_exporter = opentelemetry_otlp::new_exporter()
 ///     .tonic()
 ///     .build_metrics_exporter(
-///         Box::new(DefaultTemporalitySelector::new()),
+///         Temporality::default(),
 ///     )?;
 ///
 /// // Create a log exporter you can use when configuring logger providers
@@ -331,7 +329,7 @@ impl TonicExporterBuilder {
     #[cfg(feature = "metrics")]
     pub fn build_metrics_exporter(
         self,
-        temporality_selector: Box<dyn opentelemetry_sdk::metrics::reader::TemporalitySelector>,
+        temporality: opentelemetry_sdk::metrics::data::Temporality,
     ) -> opentelemetry::metrics::Result<crate::MetricsExporter> {
         use crate::MetricsExporter;
         use metrics::TonicMetricsClient;
@@ -345,7 +343,7 @@ impl TonicExporterBuilder {
 
         let client = TonicMetricsClient::new(channel, interceptor, compression);
 
-        Ok(MetricsExporter::new(client, temporality_selector))
+        Ok(MetricsExporter::new(client, temporality))
     }
 
     /// Build a new tonic span exporter

opentelemetry-otlp/src/lib.rs

@@ -125,7 +125,7 @@
 //! use opentelemetry::{global, KeyValue, trace::Tracer};
 //! use opentelemetry_sdk::{trace::{self, RandomIdGenerator, Sampler}, Resource};
 //! # #[cfg(feature = "metrics")]
-//! use opentelemetry_sdk::metrics::reader::DefaultTemporalitySelector;
+//! use opentelemetry_sdk::metrics::data::Temporality;
 //! use opentelemetry_otlp::{Protocol, WithExportConfig, ExportConfig};
 //! use std::time::Duration;
 //! # #[cfg(feature = "grpc-tonic")]
@@ -183,7 +183,6 @@
 //!         .with_resource(Resource::new(vec![KeyValue::new("service.name", "example")]))
 //!         .with_period(Duration::from_secs(3))
 //!         .with_timeout(Duration::from_secs(10))
-//!         .with_temporality_selector(DefaultTemporalitySelector::new())
 //!         .build();
 //!     # }
 //!

opentelemetry-otlp/src/metric.rs

@@ -14,8 +14,7 @@ use opentelemetry_sdk::{
     metrics::{
         data::{ResourceMetrics, Temporality},
         exporter::PushMetricsExporter,
-        reader::{DefaultTemporalitySelector, DeltaTemporalitySelector, TemporalitySelector},
-        InstrumentKind, PeriodicReader, SdkMeterProvider,
+        PeriodicReader, SdkMeterProvider,
     },
     runtime::Runtime,
     Resource,
@@ -47,7 +46,7 @@ impl OtlpPipeline {
     {
         OtlpMetricPipeline {
             rt,
-            temporality_selector: None,
+            temporality: None,
             exporter_pipeline: NoExporterConfig(()),
             resource: None,
             period: None,
@@ -75,22 +74,15 @@ pub enum MetricsExporterBuilder {
 
 impl MetricsExporterBuilder {
     /// Build a OTLP metrics exporter with given configuration.
-    pub fn build_metrics_exporter(
-        self,
-        temporality_selector: Box<dyn TemporalitySelector>,
-    ) -> Result<MetricsExporter> {
+    pub fn build_metrics_exporter(self, temporality: Temporality) -> Result<MetricsExporter> {
         match self {
             #[cfg(feature = "grpc-tonic")]
-            MetricsExporterBuilder::Tonic(builder) => {
-                builder.build_metrics_exporter(temporality_selector)
-            }
+            MetricsExporterBuilder::Tonic(builder) => builder.build_metrics_exporter(temporality),
             #[cfg(feature = "http-proto")]
-            MetricsExporterBuilder::Http(builder) => {
-                builder.build_metrics_exporter(temporality_selector)
-            }
+            MetricsExporterBuilder::Http(builder) => builder.build_metrics_exporter(temporality),
             #[cfg(not(any(feature = "http-proto", feature = "grpc-tonic")))]
             MetricsExporterBuilder::Unconfigured => {
-                drop(temporality_selector);
+                let _ = temporality;
                 Err(opentelemetry::metrics::MetricsError::Other(
                     "no configured metrics exporter, enable `http-proto` or `grpc-tonic` feature to configure a metrics exporter".into(),
                 ))
@@ -119,7 +111,7 @@ impl From<HttpExporterBuilder> for MetricsExporterBuilder {
 /// runtime.
 pub struct OtlpMetricPipeline<RT, EB> {
     rt: RT,
-    temporality_selector: Option<Box<dyn TemporalitySelector>>,
+    temporality: Option<Temporality>,
     exporter_pipeline: EB,
     resource: Option<Resource>,
     period: Option<time::Duration>,
@@ -154,23 +146,13 @@ where
         }
     }
 
-    /// Build with the given temporality selector
-    pub fn with_temporality_selector<T: TemporalitySelector + 'static>(self, selector: T) -> Self {
+    /// Set the [Temporality] of the exporter.
+    pub fn with_temporality(self, temporality: Temporality) -> Self {
         OtlpMetricPipeline {
-            temporality_selector: Some(Box::new(selector)),
+            temporality: Some(temporality),
             ..self
         }
     }
-
-    /// Build with delta temporality selector.
-    ///
-    /// This temporality selector is equivalent to OTLP Metrics Exporter's
-    /// `Delta` temporality preference (see [its documentation][exporter-docs]).
-    ///
-    /// [exporter-docs]: https://github.com/open-telemetry/opentelemetry-specification/blob/a1c13d59bb7d0fb086df2b3e1eaec9df9efef6cc/specification/metrics/sdk_exporters/otlp.md#additional-configuration
-    pub fn with_delta_temporality(self) -> Self {
-        self.with_temporality_selector(DeltaTemporalitySelector::new())
-    }
 }
 
 impl<RT> OtlpMetricPipeline<RT, NoExporterConfig>
@@ -185,7 +167,7 @@ where
         OtlpMetricPipeline {
             exporter_pipeline: pipeline.into(),
             rt: self.rt,
-            temporality_selector: self.temporality_selector,
+            temporality: self.temporality,
             resource: self.resource,
             period: self.period,
             timeout: self.timeout,
@@ -199,10 +181,9 @@ where
 {
     /// Build MeterProvider
     pub fn build(self) -> Result<SdkMeterProvider> {
-        let exporter = self.exporter_pipeline.build_metrics_exporter(
-            self.temporality_selector
-                .unwrap_or_else(|| Box::new(DefaultTemporalitySelector::new())),
-        )?;
+        let exporter = self
+            .exporter_pipeline
+            .build_metrics_exporter(self.temporality.unwrap_or_default())?;
 
         let mut builder = PeriodicReader::builder(exporter, self.rt);
 
@@ -247,7 +228,7 @@ pub trait MetricsClient: fmt::Debug + Send + Sync + 'static {
 /// Export metrics in OTEL format.
 pub struct MetricsExporter {
     client: Box<dyn MetricsClient>,
-    temporality_selector: Box<dyn TemporalitySelector>,
+    temporality: Temporality,
 }
 
 impl Debug for MetricsExporter {
@@ -256,12 +237,6 @@ impl Debug for MetricsExporter {
     }
 }
 
-impl TemporalitySelector for MetricsExporter {
-    fn temporality(&self, kind: InstrumentKind) -> Temporality {
-        self.temporality_selector.temporality(kind)
-    }
-}
-
 #[async_trait]
 impl PushMetricsExporter for MetricsExporter {
     async fn export(&self, metrics: &mut ResourceMetrics) -> Result<()> {
@@ -276,17 +251,18 @@ impl PushMetricsExporter for MetricsExporter {
     fn shutdown(&self) -> Result<()> {
         self.client.shutdown()
     }
+
+    fn temporality(&self) -> Temporality {
+        self.temporality
+    }
 }
 
 impl MetricsExporter {
     /// Create a new metrics exporter
-    pub fn new(
-        client: impl MetricsClient,
-        temporality_selector: Box<dyn TemporalitySelector>,
-    ) -> MetricsExporter {
+    pub fn new(client: impl MetricsClient, temporality: Temporality) -> MetricsExporter {
         MetricsExporter {
             client: Box::new(client),
-            temporality_selector,
+            temporality,
         }
     }
 }

opentelemetry-sdk/CHANGELOG.md

@@ -5,6 +5,8 @@
 - Bump MSRV to 1.70 [#2179](https://github.com/open-telemetry/opentelemetry-rust/pull/2179)
 - Implement `LogRecord::set_trace_context` for `LogRecord`. Respect any trace context set on a `LogRecord` when emitting through a `Logger`.
 - Improved `LoggerProvider` shutdown handling to prevent redundant shutdown calls when `drop` is invoked. [#2195](https://github.com/open-telemetry/opentelemetry-rust/pull/2195)
+- **BREAKING**: [#2217](https://github.com/open-telemetry/opentelemetry-rust/pull/2217)
+  - **Replaced**: Removed `{Delta,Cumulative}TemporalitySelector::new()` in favor of directly using `Temporality` enum to simplify the configuration of MetricExporterBuilder with different temporalities.
 
 ## v0.26.0
 Released 2024-Sep-30

opentelemetry-sdk/benches/metric.rs

@@ -10,7 +10,7 @@ use opentelemetry_sdk::{
     metrics::{
         data::{ResourceMetrics, Temporality},
         new_view,
-        reader::{DeltaTemporalitySelector, MetricReader, TemporalitySelector},
+        reader::MetricReader,
         Aggregation, Instrument, InstrumentKind, ManualReader, Pipeline, SdkMeterProvider, Stream,
         View,
     },
@@ -20,12 +20,6 @@ use opentelemetry_sdk::{
 #[derive(Clone, Debug)]
 struct SharedReader(Arc<dyn MetricReader>);
 
-impl TemporalitySelector for SharedReader {
-    fn temporality(&self, kind: InstrumentKind) -> Temporality {
-        self.0.temporality(kind)
-    }
-}
-
 impl MetricReader for SharedReader {
     fn register_pipeline(&self, pipeline: Weak<Pipeline>) {
         self.0.register_pipeline(pipeline)
@@ -42,6 +36,10 @@ impl MetricReader for SharedReader {
     fn shutdown(&self) -> Result<()> {
         self.0.shutdown()
     }
+
+    fn temporality(&self, kind: InstrumentKind) -> Temporality {
+        self.0.temporality(kind)
+    }
 }
 
 // * Summary *
@@ -118,7 +116,7 @@ fn bench_counter(view: Option<Box<dyn View>>, temporality: &str) -> (SharedReade
     } else {
         SharedReader(Arc::new(
             ManualReader::builder()
-                .with_temporality_selector(DeltaTemporalitySelector::new())
+                .with_temporality(Temporality::Delta)
                 .build(),
         ))
     };

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

@@ -1,16 +1,22 @@
 /// Defines the window that an aggregation was calculated over.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Copy, Clone, Default, PartialEq, Eq, Hash)]
 #[non_exhaustive]
 pub enum Temporality {
     /// A measurement interval that continues to expand forward in time from a
     /// starting point.
     ///
     /// New measurements are added to all previous measurements since a start time.
+    #[default]
     Cumulative,
 
     /// A measurement interval that resets each cycle.
     ///
     /// Measurements from one cycle are recorded independently, measurements from
     /// other cycles do not affect them.
     Delta,
+
+    /// Configures Synchronous Counter and Histogram instruments to use
+    /// Delta aggregation temporality, which allows them to shed memory
+    /// following a cardinality explosion, thus use less memory.
+    LowMemory,
 }