Workaround for temporality configuration not being possible (#610)

Author: JonasKunz

CHANGELOG.next-release.md

@@ -1 +1 @@
-
+* Fix `otel.exporter.otlp.metrics.temporality.preference` config option having no effect. - #610

custom/build.gradle.kts

@@ -35,7 +35,9 @@ dependencies {
   // test dependencies
   testImplementation(project(":testing-common"))
   testImplementation("io.opentelemetry:opentelemetry-sdk")
+  testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
+  testImplementation("io.opentelemetry:opentelemetry-exporter-otlp")
   testImplementation("io.opentelemetry.javaagent:opentelemetry-javaagent-tooling") {
     //The following dependency isn't actually needed, but breaks the classpath when testing with Java 8
     exclude(group = "io.opentelemetry.javaagent", module = "opentelemetry-javaagent-tooling-java9")

custom/src/main/java/co/elastic/otel/ElasticUserAgentHeader.java

@@ -47,12 +47,23 @@ public static SpanExporter configureIfPossible(SpanExporter spanExporter) {
   }
 
   public static MetricExporter configureIfPossible(MetricExporter metricExporter) {
+    // TODO remove workaround for https://github.com/open-telemetry/opentelemetry-java/issues/7276
+    // once fixed, setAggregationTemporalitySelector and setDefaultAggregationSelector can then be
+    // removed
     if (metricExporter instanceof OtlpGrpcMetricExporter) {
       return ((OtlpGrpcMetricExporter) metricExporter)
-          .toBuilder().addHeader(HEADER_NAME, GRPC_VALUE).build();
+          .toBuilder()
+              .setAggregationTemporalitySelector(metricExporter)
+              .setDefaultAggregationSelector(metricExporter)
+              .addHeader(HEADER_NAME, GRPC_VALUE)
+              .build();
     } else if (metricExporter instanceof OtlpHttpMetricExporter) {
       return ((OtlpHttpMetricExporter) metricExporter)
-          .toBuilder().addHeader(HEADER_NAME, HTTP_VALUE).build();
+          .toBuilder()
+              .setAggregationTemporalitySelector(metricExporter)
+              .setDefaultAggregationSelector(metricExporter)
+              .addHeader(HEADER_NAME, HTTP_VALUE)
+              .build();
     }
     return metricExporter;
   }

custom/src/test/java/co/elastic/otel/ElasticAutoConfigurationCustomizerProviderTest.java

@@ -22,12 +22,22 @@
 import static co.elastic.otel.ElasticAutoConfigurationCustomizerProvider.resourceProviders;
 import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.assertThat;
 
+import co.elastic.otel.testing.OtelReflectionUtils;
+import io.opentelemetry.exporter.otlp.http.metrics.OtlpHttpMetricExporter;
 import io.opentelemetry.javaagent.tooling.EmptyConfigProperties;
+import io.opentelemetry.sdk.OpenTelemetrySdk;
+import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import io.opentelemetry.sdk.metrics.InstrumentType;
+import io.opentelemetry.sdk.metrics.data.AggregationTemporality;
+import io.opentelemetry.sdk.metrics.export.AggregationTemporalitySelector;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.semconv.incubating.DeploymentIncubatingAttributes;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
+import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 class ElasticAutoConfigurationCustomizerProviderTest {
@@ -88,6 +98,50 @@ void customizeMetricTemporalityPreference() {
     assertThat(value).isEqualTo("LOWMEMORY");
   }
 
+  @Test
+  void testTemporalityWorkaroundStilLRequired() {
+    // Verifies that the workaround for
+    // https://github.com/open-telemetry/opentelemetry-java/issues/7276
+    // is still required. Once not needed anymore, fix the TODO in
+    // co.elastic.otel.ElasticUserAgentHeader and remove this test
+
+    OtlpHttpMetricExporter original =
+        OtlpHttpMetricExporter.builder()
+            .setAggregationTemporalitySelector(AggregationTemporalitySelector.deltaPreferred())
+            .build();
+    Assertions.assertThat(original.getAggregationTemporality(InstrumentType.COUNTER))
+        .isEqualTo(AggregationTemporality.DELTA);
+
+    OtlpHttpMetricExporter modified = original.toBuilder().build();
+
+    // The bug causes the temporality to become cumulative, though it should be delta
+    assertThat(modified.getAggregationTemporality(InstrumentType.COUNTER))
+        .isEqualTo(AggregationTemporality.CUMULATIVE);
+  }
+
+  @Test
+  void verifyDefaultTemporalityOverriddenToDelta() {
+    try (OpenTelemetrySdk sdk =
+        AutoConfiguredOpenTelemetrySdk.builder().build().getOpenTelemetrySdk()) {
+      List<MetricExporter> metricExporters =
+          OtelReflectionUtils.extractMetricExporters(sdk.getSdkMeterProvider());
+
+      assertThat(metricExporters).hasSize(1);
+
+      MetricExporter otlp = metricExporters.get(0);
+      assertThat(otlp.getAggregationTemporality(InstrumentType.COUNTER))
+          .isEqualTo(AggregationTemporality.DELTA);
+      assertThat(otlp.getAggregationTemporality(InstrumentType.OBSERVABLE_COUNTER))
+          .isEqualTo(AggregationTemporality.DELTA);
+      assertThat(otlp.getAggregationTemporality(InstrumentType.HISTOGRAM))
+          .isEqualTo(AggregationTemporality.DELTA);
+      assertThat(otlp.getAggregationTemporality(InstrumentType.UP_DOWN_COUNTER))
+          .isEqualTo(AggregationTemporality.CUMULATIVE);
+      assertThat(otlp.getAggregationTemporality(InstrumentType.OBSERVABLE_UP_DOWN_COUNTER))
+          .isEqualTo(AggregationTemporality.CUMULATIVE);
+    }
+  }
+
   @Test
   void legacyDeploymentEnvironment() {
     Resource input =

testing-common/src/main/java/co/elastic/otel/testing/OtelReflectionUtils.java

@@ -22,6 +22,10 @@
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.trace.TracerProvider;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
+import io.opentelemetry.sdk.metrics.SdkMeterProvider;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.metrics.export.PeriodicMetricReader;
+import io.opentelemetry.sdk.metrics.internal.export.RegisteredReader;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
 import io.opentelemetry.sdk.trace.SpanProcessor;
 import java.lang.reflect.Field;
@@ -119,4 +123,16 @@ private static Object readField(Class<?> clazz, Object instance, String fieldNam
       throw new IllegalStateException(e);
     }
   }
+
+  @SuppressWarnings("unchecked")
+  public static List<MetricExporter> extractMetricExporters(SdkMeterProvider sdkMeterProvider) {
+    List<RegisteredReader> readers =
+        (List<RegisteredReader>) readField(sdkMeterProvider, "registeredReaders");
+
+    return readers.stream()
+        .map(reader -> reader.getReader())
+        .filter(reader -> reader instanceof PeriodicMetricReader)
+        .map(periodicReader -> (MetricExporter) readField(periodicReader, "exporter"))
+        .collect(Collectors.toList());
+  }
 }