Added MetricReader customizer for AutoConfiguredOpenTelemetrySdkBuilder

docs/apidiffs/current_vs_latest/opentelemetry-sdk-extension-autoconfigure-spi.txt

@@ -1,2 +1,4 @@
 Comparing source compatibility of  against 
-No changes.
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer addMetricReaderCustomizer(java.util.function.BiFunction<? super io.opentelemetry.sdk.metrics.export.MetricReader,io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties,? extends io.opentelemetry.sdk.metrics.export.MetricReader>)

docs/apidiffs/current_vs_latest/opentelemetry-sdk-extension-autoconfigure.txt

@@ -1,2 +1,4 @@
 Comparing source compatibility of  against 
-No changes.
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdkBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer addMetricReaderCustomizer(java.util.function.BiFunction<? super io.opentelemetry.sdk.metrics.export.MetricReader,io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties,? extends io.opentelemetry.sdk.metrics.export.MetricReader>)

sdk-extensions/autoconfigure-spi/src/main/java/io/opentelemetry/sdk/autoconfigure/spi/AutoConfigurationCustomizer.java

@@ -11,6 +11,7 @@
 import io.opentelemetry.sdk.logs.export.LogRecordExporter;
 import io.opentelemetry.sdk.metrics.SdkMeterProviderBuilder;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.metrics.export.MetricReader;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
 import io.opentelemetry.sdk.trace.SpanProcessor;
@@ -150,12 +151,25 @@ default AutoConfigurationCustomizer addMeterProviderCustomizer(
    *
    * <p>Multiple calls will execute the customizers in order.
    */
+  @SuppressWarnings("UnusedReturnValue")
   default AutoConfigurationCustomizer addMetricExporterCustomizer(
       BiFunction<? super MetricExporter, ConfigProperties, ? extends MetricExporter>
           exporterCustomizer) {
     return this;
   }
 
+  /**
+   * Adds a {@link BiFunction} to invoke with the autoconfigured {@link MetricReader} to allow
+   * customization. The return value of the {@link BiFunction} will replace the passed-in argument.
+   *
+   * <p>Multiple calls will execute the customizers in order.
+   */
+  @SuppressWarnings("UnusedReturnValue")
+  default AutoConfigurationCustomizer addMetricReaderCustomizer(
+      BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader> readerCustomizer) {
+    return this;
+  }
+
   /**
    * Adds a {@link BiFunction} to invoke the with the {@link SdkLoggerProviderBuilder} to allow
    * customization. The return value of the {@link BiFunction} will replace the passed-in argument.

sdk-extensions/autoconfigure/build.gradle.kts

@@ -53,6 +53,7 @@ testing {
         implementation(project(":exporters:logging-otlp"))
         implementation(project(":exporters:otlp:all"))
         implementation(project(":exporters:prometheus"))
+        implementation("io.prometheus:prometheus-metrics-exporter-httpserver")
         implementation(project(":exporters:zipkin"))
         implementation(project(":sdk:testing"))
         implementation(project(":sdk:trace-shaded-deps"))

sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkBuilder.java

@@ -28,6 +28,7 @@
 import io.opentelemetry.sdk.metrics.SdkMeterProvider;
 import io.opentelemetry.sdk.metrics.SdkMeterProviderBuilder;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.metrics.export.MetricReader;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
 import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
@@ -83,6 +84,8 @@ public final class AutoConfiguredOpenTelemetrySdkBuilder implements AutoConfigur
       meterProviderCustomizer = (a, unused) -> a;
   private BiFunction<? super MetricExporter, ConfigProperties, ? extends MetricExporter>
       metricExporterCustomizer = (a, unused) -> a;
+  private BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader>
+      metricReaderCustomizer = (a, unused) -> a;
 
   private BiFunction<SdkLoggerProviderBuilder, ConfigProperties, SdkLoggerProviderBuilder>
       loggerProviderCustomizer = (a, unused) -> a;
@@ -283,6 +286,20 @@ public AutoConfiguredOpenTelemetrySdkBuilder addMetricExporterCustomizer(
     return this;
   }
 
+  /**
+   * Adds a {@link BiFunction} to invoke with the autoconfigured {@link MetricReader} to allow
+   * customization. The return value of the {@link BiFunction} will replace the passed-in argument.
+   *
+   * <p>Multiple calls will execute the customizers in order.
+   */
+  @Override
+  public AutoConfigurationCustomizer addMetricReaderCustomizer(
+      BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader> readerCustomizer) {
+    requireNonNull(readerCustomizer, "readerCustomizer");
+    this.metricReaderCustomizer = mergeCustomizer(this.metricReaderCustomizer, readerCustomizer);
+    return this;
+  }
+
   /**
    * Adds a {@link BiFunction} to invoke the with the {@link SdkLoggerProviderBuilder} to allow
    * customization. The return value of the {@link BiFunction} will replace the passed-in argument.
@@ -406,7 +423,12 @@ public AutoConfiguredOpenTelemetrySdk build() {
         SdkMeterProviderBuilder meterProviderBuilder = SdkMeterProvider.builder();
         meterProviderBuilder.setResource(resource);
         MeterProviderConfiguration.configureMeterProvider(
-            meterProviderBuilder, config, spiHelper, metricExporterCustomizer, closeables);
+            meterProviderBuilder,
+            config,
+            spiHelper,
+            metricReaderCustomizer,
+            metricExporterCustomizer,
+            closeables);
         meterProviderBuilder = meterProviderCustomizer.apply(meterProviderBuilder, config);
         SdkMeterProvider meterProvider = meterProviderBuilder.build();
         closeables.add(meterProvider);

sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/MeterProviderConfiguration.java

@@ -29,6 +29,8 @@ static void configureMeterProvider(
       SdkMeterProviderBuilder meterProviderBuilder,
       ConfigProperties config,
       SpiHelper spiHelper,
+      BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader>
+          metricReaderCustomizer,
       BiFunction<? super MetricExporter, ConfigProperties, ? extends MetricExporter>
           metricExporterCustomizer,
       List<Closeable> closeables) {
@@ -56,7 +58,8 @@ static void configureMeterProvider(
       throw new ConfigurationException("otel.experimental.metrics.cardinality.limit must be >= 1");
     }
 
-    configureMetricReaders(config, spiHelper, metricExporterCustomizer, closeables)
+    configureMetricReaders(
+            config, spiHelper, metricReaderCustomizer, metricExporterCustomizer, closeables)
         .forEach(
             reader ->
                 SdkMeterProviderUtil.registerMetricReaderWithCardinalitySelector(
@@ -66,6 +69,8 @@ static void configureMeterProvider(
   static List<MetricReader> configureMetricReaders(
       ConfigProperties config,
       SpiHelper spiHelper,
+      BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader>
+          metricReaderCustomizer,
       BiFunction<? super MetricExporter, ConfigProperties, ? extends MetricExporter>
           metricExporterCustomizer,
       List<Closeable> closeables) {
@@ -85,7 +90,12 @@ static List<MetricReader> configureMetricReaders(
         .map(
             exporterName ->
                 MetricExporterConfiguration.configureReader(
-                    exporterName, config, spiHelper, metricExporterCustomizer, closeables))
+                    exporterName,
+                    config,
+                    spiHelper,
+                    metricReaderCustomizer,
+                    metricExporterCustomizer,
+                    closeables))
         .collect(Collectors.toList());
   }
 

sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/MetricExporterConfiguration.java

@@ -42,6 +42,8 @@ static MetricReader configureReader(
       String name,
       ConfigProperties config,
       SpiHelper spiHelper,
+      BiFunction<? super MetricReader, ConfigProperties, ? extends MetricReader>
+          metricReaderCustomizer,
       BiFunction<? super MetricExporter, ConfigProperties, ? extends MetricExporter>
           metricExporterCustomizer,
       List<Closeable> closeables) {
@@ -56,7 +58,14 @@ static MetricReader configureReader(
       MetricReader metricReader = configureMetricReader(name, spiMetricReadersManager);
       if (metricReader != null) {
         closeables.add(metricReader);
-        return metricReader;
+
+        // Customize metric reader
+        MetricReader customizedMetricReader = metricReaderCustomizer.apply(metricReader, config);
+        if (customizedMetricReader != metricReader) {
+          closeables.add(customizedMetricReader);
+        }
+
+        return customizedMetricReader;
       }
       // No exporter or reader with the name
       throw new ConfigurationException("Unrecognized value for otel.metrics.exporter: " + name);
@@ -74,7 +83,11 @@ static MetricReader configureReader(
             .setInterval(config.getDuration("otel.metric.export.interval", DEFAULT_EXPORT_INTERVAL))
             .build();
     closeables.add(reader);
-    return reader;
+    MetricReader customizedMetricReader = metricReaderCustomizer.apply(reader, config);
+    if (customizedMetricReader != reader) {
+      closeables.add(customizedMetricReader);
+    }
+    return customizedMetricReader;
   }
 
   // Visible for testing

sdk-extensions/autoconfigure/src/test/java/io/opentelemetry/sdk/autoconfigure/MeterProviderConfigurationTest.java

@@ -54,6 +54,7 @@ private static ObjectAssert<ExemplarFilter> assertExemplarFilter(Map<String, Str
         DefaultConfigProperties.createFromMap(configWithDefault),
         SpiHelper.create(MeterProviderConfigurationTest.class.getClassLoader()),
         (a, b) -> a,
+        (a, b) -> a,
         new ArrayList<>());
     return assertThat(builder)
         .extracting("exemplarFilter", as(InstanceOfAssertFactories.type(ExemplarFilter.class)));

sdk-extensions/autoconfigure/src/testFullConfig/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkTest.java

@@ -5,12 +5,16 @@
 
 package io.opentelemetry.sdk.autoconfigure;
 
+import static java.util.Collections.singletonMap;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
 
+import com.linecorp.armeria.client.WebClient;
 import io.github.netmikey.logunit.api.LogCapturer;
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.events.GlobalEventEmitterProvider;
+import io.opentelemetry.exporter.prometheus.PrometheusHttpServer;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import java.lang.reflect.Field;
 import org.junit.jupiter.api.BeforeEach;
@@ -31,6 +35,25 @@ void setUp() {
     GlobalEventEmitterProvider.resetForTest();
   }
 
+  @SuppressWarnings("ResultOfMethodCallIgnored")
+  @Test
+  void build_addMetricReaderCustomizerPrometheus() {
+    AutoConfiguredOpenTelemetrySdkBuilder builder = AutoConfiguredOpenTelemetrySdk.builder();
+    builder.addPropertiesSupplier(() -> singletonMap("otel.metrics.exporter", "prometheus"));
+
+    int port = FreePortFinder.getFreePort();
+    builder.addMetricReaderCustomizer(
+        (reader, config) -> {
+          assertThat(reader).isInstanceOf(PrometheusHttpServer.class);
+          return PrometheusHttpServer.builder().setPort(port).build();
+        });
+
+    try (OpenTelemetrySdk ignored = builder.build().getOpenTelemetrySdk()) {
+      WebClient client = WebClient.builder("http://localhost:" + port).build();
+      assertThatCode(() -> client.get("/metrics")).doesNotThrowAnyException();
+    }
+  }
+
   @Test
   void initializeAndGet() {
     try (OpenTelemetrySdk sdk = AutoConfiguredOpenTelemetrySdk.initialize().getOpenTelemetrySdk()) {

sdk-extensions/autoconfigure/src/testFullConfig/java/io/opentelemetry/sdk/autoconfigure/ConfigurableMetricExporterTest.java

@@ -87,7 +87,7 @@ void configureMetricReaders_multipleWithNone() {
     assertThatThrownBy(
             () ->
                 MeterProviderConfiguration.configureMetricReaders(
-                    config, spiHelper, (a, unused) -> a, closeables))
+                    config, spiHelper, (a, unused) -> a, (a, unused) -> a, closeables))
         .isInstanceOf(ConfigurationException.class)
         .hasMessageContaining("otel.metrics.exporter contains none along with other exporters");
     cleanup.addCloseables(closeables);
@@ -102,7 +102,11 @@ void configureMetricReaders_defaultExporter() {
 
     List<MetricReader> metricReaders =
         MeterProviderConfiguration.configureMetricReaders(
-            config, spiHelper, (metricExporter, unused) -> metricExporter, closeables);
+            config,
+            spiHelper,
+            (a, unused) -> a,
+            (metricExporter, unused) -> metricExporter,
+            closeables);
     cleanup.addCloseables(closeables);
 
     assertThat(metricReaders)
@@ -125,7 +129,11 @@ void configureMetricReaders_multipleExporters() {
 
     List<MetricReader> metricReaders =
         MeterProviderConfiguration.configureMetricReaders(
-            config, spiHelper, (metricExporter, unused) -> metricExporter, closeables);
+            config,
+            spiHelper,
+            (a, unused) -> a,
+            (metricExporter, unused) -> metricExporter,
+            closeables);
     cleanup.addCloseables(closeables);
 
     assertThat(metricReaders).hasSize(2).hasOnlyElementsOfType(PeriodicMetricReader.class);

sdk-extensions/autoconfigure/src/testFullConfig/java/io/opentelemetry/sdk/autoconfigure/FreePortFinder.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+
+final class FreePortFinder {
+
+  static int getFreePort() {
+    try (ServerSocket socket = new ServerSocket(0)) {
+      return socket.getLocalPort();
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private FreePortFinder() {}
+}

sdk-extensions/autoconfigure/src/testFullConfig/java/io/opentelemetry/sdk/autoconfigure/MeterProviderConfigurationTest.java

@@ -50,6 +50,7 @@ void configureMeterProvider_InvalidCardinalityLimit() {
                           "0")),
                   spiHelper,
                   (a, b) -> a,
+                  (a, b) -> a,
                   closeables);
             })
         .isInstanceOf(ConfigurationException.class)
@@ -69,6 +70,7 @@ void configureMeterProvider_ConfiguresCardinalityLimit() {
             Collections.singletonMap("otel.metrics.exporter", "logging")),
         spiHelper,
         (a, b) -> a,
+        (a, b) -> a,
         closeables);
     cleanup.addCloseables(closeables);
     assertCardinalityLimit(builder, 2000);
@@ -85,6 +87,7 @@ void configureMeterProvider_ConfiguresCardinalityLimit() {
                 "100")),
         spiHelper,
         (a, b) -> a,
+        (a, b) -> a,
         closeables);
     cleanup.addCloseables(closeables);
     assertCardinalityLimit(builder, 100);