feat: use exponential histograms for the quickstart sample

samples/instrumentation-quickstart/docker-compose.yaml

@@ -29,7 +29,7 @@ services:
     depends_on:
       - otelcol
   otelcol:
-    image: otel/opentelemetry-collector-contrib:0.110.0
+    image: otel/opentelemetry-collector-contrib:0.115.1
     volumes:
       - ./otel-collector-config.yaml:/etc/otelcol-contrib/config.yaml:ro
       - logs:/var/log:ro

samples/instrumentation-quickstart/otel-collector-config.yaml

@@ -109,6 +109,14 @@ processors:
     detectors: ["env", "gcp"]
 
 service:
+  telemetry:
+    metrics:
+      readers:
+        - pull:
+            exporter:
+              prometheus:
+                host: '0.0.0.0'
+                port: 8888
   pipelines:
     traces:
       receivers: ["otlp"]

samples/instrumentation-quickstart/src/instrumentation.ts

@@ -29,6 +29,9 @@ import {
 import {
   ConsoleMetricExporter,
   PeriodicExportingMetricReader,
+  ExponentialHistogramAggregation,
+  DefaultAggregation,
+  InstrumentType,
 } from '@opentelemetry/sdk-metrics';
 import {OTLPMetricExporter} from '@opentelemetry/exporter-metrics-otlp-proto';
 
@@ -48,7 +51,17 @@ function getMetricReader() {
       diag.info('using otel metrics exporter');
       return new PeriodicExportingMetricReader({
         ...readerOptions,
-        exporter: new OTLPMetricExporter(),
+        exporter: new OTLPMetricExporter({
+          // Use exponential histograms for histogram instruments.
+          // This can be done using an environment variable after
+          // https://github.com/open-telemetry/opentelemetry-js/issues/3920 is implemented.
+          aggregationPreference: (instrumentType: InstrumentType) =>  {
+            if (instrumentType === InstrumentType.HISTOGRAM) {
+              return new ExponentialHistogramAggregation()
+            }
+            return new DefaultAggregation()
+          }
+        }),
       });
     case 'console':
       return new PeriodicExportingMetricReader({