Start adding metrics advanced (view) examples (#1170)

Author: cijothomas

Cargo.toml

@@ -27,6 +27,7 @@ members = [
     "opentelemetry-otlp/examples/basic-otlp-http",
     "opentelemetry-otlp/examples/external-otlp-grpcio-async-std",
     "examples/metrics-basic",
+    "examples/metrics-advanced",
     "examples/logs-basic",
     "examples/traceresponse",
     "examples/tracing-grpc",

examples/metrics-advanced/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "metrics-advanced"
+version = "0.1.0"
+edition = "2021"
+license = "Apache-2.0"
+publish = false
+
+[dependencies]
+opentelemetry_api = { path = "../../opentelemetry-api", features = ["metrics"] }
+opentelemetry_sdk = { path = "../../opentelemetry-sdk", features = ["metrics", "rt-tokio"] }
+opentelemetry-stdout = { path = "../../opentelemetry-stdout", features = ["metrics"]}
+tokio = { version = "1.0", features = ["full"] }

examples/metrics-advanced/README.md

@@ -0,0 +1,17 @@
+# Metric SDK Advanced Configuration Example
+
+This example shows how to customize the OpenTelemetry Rust Metric SDK. This
+shows how to change temporality, how to customize the aggregation using the
+concept of "Views" etc. The examples write output to stdout, but could be
+replaced with other exporters.
+
+## Usage
+
+Run the following, and the Metrics will be written out to stdout.
+
+```shell
+$ cargo run
+```
+
+
+

examples/metrics-advanced/src/main.rs

@@ -0,0 +1,94 @@
+use opentelemetry_api::metrics::Unit;
+use opentelemetry_api::Key;
+use opentelemetry_api::{metrics::MeterProvider as _, KeyValue};
+use opentelemetry_sdk::metrics::{Instrument, MeterProvider, PeriodicReader, Stream};
+use opentelemetry_sdk::{runtime, Resource};
+use std::error::Error;
+
+fn init_meter_provider() -> MeterProvider {
+    // for example 1
+    let my_view_rename_and_unit = |i: &Instrument| {
+        if i.name == "my_histogram" {
+            Some(
+                Stream::new()
+                    .name("my_histogram_renamed")
+                    .unit(Unit::new("milliseconds")),
+            )
+        } else {
+            None
+        }
+    };
+
+    // for example 2
+    let my_view_drop_attributes = |i: &Instrument| {
+        if i.name == "my_counter" {
+            Some(Stream::new().allowed_attribute_keys(vec![Key::from("mykey1")]))
+        } else {
+            None
+        }
+    };
+
+    let exporter = opentelemetry_stdout::MetricsExporter::default();
+    let reader = PeriodicReader::builder(exporter, runtime::Tokio).build();
+    MeterProvider::builder()
+        .with_reader(reader)
+        .with_resource(Resource::new(vec![KeyValue::new(
+            "service.name",
+            "metrics-advanced-example",
+        )]))
+        .with_view(my_view_rename_and_unit)
+        .with_view(my_view_drop_attributes)
+        .build()
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
+    let meter_provider = init_meter_provider();
+    let meter = meter_provider.meter("mylibraryname");
+
+    // Example 1 - Rename metric using View.
+    // This instrument will be renamed to "my_histogram_renamed",
+    // and its unit changed to "milliseconds"
+    // using view.
+    let histogram = meter
+        .f64_histogram("my_histogram")
+        .with_unit(Unit::new("ms"))
+        .with_description("My histogram example description")
+        .init();
+
+    // Record measurements using the histogram instrument.
+    histogram.record(
+        10.5,
+        [
+            KeyValue::new("mykey1", "myvalue1"),
+            KeyValue::new("mykey2", "myvalue2"),
+            KeyValue::new("mykey3", "myvalue3"),
+            KeyValue::new("mykey4", "myvalue4"),
+        ]
+        .as_ref(),
+    );
+
+    // Example 2 - Drop unwanted attributes using view.
+    let counter = meter.u64_counter("my_counter").init();
+
+    // Record measurements using the Counter instrument.
+    // Though we are passing 4 attributes here, only 1 will be used
+    // for aggregation as view is configured to use only "mykey1"
+    // attribute.
+    counter.add(
+        10,
+        [
+            KeyValue::new("mykey1", "myvalue1"),
+            KeyValue::new("mykey2", "myvalue2"),
+            KeyValue::new("mykey3", "myvalue3"),
+            KeyValue::new("mykey4", "myvalue4"),
+        ]
+        .as_ref(),
+    );
+
+    // Metrics are exported by default every 30 seconds when using stdout exporter,
+    // however shutting down the MeterProvider here instantly flushes
+    // the metrics, instead of waiting for the 30 sec interval.
+    meter_provider.shutdown()?;
+    Ok(())
+}

examples/metrics-basic/src/main.rs

@@ -104,7 +104,7 @@ async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
         .as_ref(),
     );
 
-    // Note that there is no ObservableHistogram instruments.
+    // Note that there is no ObservableHistogram instrument.
 
     // Create a ObservableGauge instrument and register a callback that reports the measurement.
     let gauge = meter
@@ -128,7 +128,7 @@ async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
 
     // Note that Gauge only has a Observable version.
 
-    // Metrics are exported by default every 30 seconds,
+    // Metrics are exported by default every 30 seconds when using stdout exporter,
     // however shutting down the MeterProvider here instantly flushes
     // the metrics, instead of waiting for the 30 sec interval.
     meter_provider.shutdown()?;