add ComponentLoader to support more auto configuration scenarios, e.g…

…. spring boot

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

@@ -1,2 +1,13 @@
 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.AutoConfiguredOpenTelemetrySdkBuilder setComponentLoader(io.opentelemetry.sdk.autoconfigure.ComponentLoader)
++++* NEW INTERFACE: PUBLIC(+) ABSTRACT(+) io.opentelemetry.sdk.autoconfigure.ComponentLoader  (not serializable)
+	+++  CLASS FILE FORMAT VERSION: 52.0 <- n.a.
+	+++  NEW SUPERCLASS: java.lang.Object
+	+++* NEW METHOD: PUBLIC(+) ABSTRACT(+) java.lang.Iterable<T> load(java.lang.Class<T>)
+		GENERIC TEMPLATES: +++ T:java.lang.Object
+	+++* NEW METHOD: PUBLIC(+) java.util.Map<java.lang.String,T> loadConfigurableProviders(java.lang.Class<T>)
+		GENERIC TEMPLATES: +++ T:io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider
+	+++* NEW METHOD: PUBLIC(+) java.util.List<T> loadOrdered(java.lang.Class<T>)
+		GENERIC TEMPLATES: +++ T:io.opentelemetry.sdk.autoconfigure.spi.Ordered

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

@@ -15,7 +15,7 @@
  * #getPropagator(ConfigProperties)} will be enabled and available as part of {@link
  * OpenTelemetry#getPropagators()}.
  */
-public interface ConfigurablePropagatorProvider {
+public interface ConfigurablePropagatorProvider extends ConfigurableProvider {
   /**
    * Returns a {@link TextMapPropagator} that can be registered to OpenTelemetry by providing the
    * property value specified by {@link #getName()}.
@@ -27,5 +27,6 @@ public interface ConfigurablePropagatorProvider {
    * property to enable it. If the name is the same as any other defined propagator name, it is
    * undefined which will be used.
    */
+  @Override
   String getName();
 }

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

@@ -0,0 +1,17 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure.spi;
+
+/**
+ * A named configurable provider.
+ *
+ * <p>It can be used to generically determine if a provider should be replaced by another provider
+ * with the same name.
+ */
+public interface ConfigurableProvider {
+  /** Returns the name of this provider. */
+  String getName();
+}

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

@@ -6,6 +6,7 @@
 package io.opentelemetry.sdk.autoconfigure.spi.internal;
 
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
 import io.opentelemetry.sdk.autoconfigure.spi.metrics.ConfigurableMetricExporterProvider;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import io.opentelemetry.sdk.metrics.export.MetricReader;
@@ -24,7 +25,7 @@
  * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
  * at any time.
  */
-public interface ConfigurableMetricReaderProvider {
+public interface ConfigurableMetricReaderProvider extends ConfigurableProvider {
 
   /**
    * Returns a {@link MetricReader} that can be registered to OpenTelemetry by providing the
@@ -40,5 +41,6 @@ public interface ConfigurableMetricReaderProvider {
    * name, the resulting behavior is undefined and it is explicitly unspecified which reader /
    * exporter will actually be used.
    */
+  @Override
   String getName();
 }

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

@@ -6,6 +6,7 @@
 package io.opentelemetry.sdk.autoconfigure.spi.logs;
 
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
 import io.opentelemetry.sdk.logs.export.LogRecordExporter;
 
 /**
@@ -16,7 +17,7 @@
  *
  * @since 1.19.0
  */
-public interface ConfigurableLogRecordExporterProvider {
+public interface ConfigurableLogRecordExporterProvider extends ConfigurableProvider {
 
   /**
    * Returns a {@link LogRecordExporter} that can be registered to OpenTelemetry by providing the
@@ -30,5 +31,6 @@ public interface ConfigurableLogRecordExporterProvider {
    * the name does conflict with another exporter name, the resulting behavior is undefined and it
    * is explicitly unspecified which exporter will actually be used.
    */
+  @Override
   String getName();
 }

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

@@ -6,6 +6,7 @@
 package io.opentelemetry.sdk.autoconfigure.spi.metrics;
 
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.ConfigurableMetricReaderProvider;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import io.opentelemetry.sdk.metrics.export.MetricReader;
@@ -22,7 +23,7 @@
  *
  * @since 1.15.0
  */
-public interface ConfigurableMetricExporterProvider {
+public interface ConfigurableMetricExporterProvider extends ConfigurableProvider {
 
   /**
    * Returns a {@link MetricExporter} that can be registered to OpenTelemetry by providing the
@@ -38,5 +39,6 @@ public interface ConfigurableMetricExporterProvider {
    * name, the resulting behavior is undefined and it is explicitly unspecified which exporter /
    * reader will actually be used.
    */
+  @Override
   String getName();
 }

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

@@ -6,6 +6,7 @@
 package io.opentelemetry.sdk.autoconfigure.spi.traces;
 
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 
 /**
@@ -14,7 +15,7 @@
  * returned by {@link #getName()}, the sampler returned by {@link #createSampler(ConfigProperties)}
  * will be enabled and added to the SDK.
  */
-public interface ConfigurableSamplerProvider {
+public interface ConfigurableSamplerProvider extends ConfigurableProvider {
 
   /**
    * Returns a {@link Sampler} that can be registered to OpenTelemetry by providing the property
@@ -28,5 +29,6 @@ public interface ConfigurableSamplerProvider {
    * the name does conflict with another exporter name, the resulting behavior is undefined and it
    * is explicitly unspecified which exporter will actually be used.
    */
+  @Override
   String getName();
 }

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

@@ -6,6 +6,7 @@
 package io.opentelemetry.sdk.autoconfigure.spi.traces;
 
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 
 /**
@@ -14,7 +15,7 @@
  * is returned by {@link #getName()}, the exporter returned by {@link
  * #createExporter(ConfigProperties)} will be enabled and added to the SDK.
  */
-public interface ConfigurableSpanExporterProvider {
+public interface ConfigurableSpanExporterProvider extends ConfigurableProvider {
 
   /**
    * Returns a {@link SpanExporter} that can be registered to OpenTelemetry by providing the
@@ -28,5 +29,6 @@ public interface ConfigurableSpanExporterProvider {
    * the name does conflict with another exporter name, the resulting behavior is undefined and it
    * is explicitly unspecified which exporter will actually be used.
    */
+  @Override
   String getName();
 }

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

@@ -368,6 +368,12 @@ public AutoConfiguredOpenTelemetrySdkBuilder setServiceClassLoader(
     return this;
   }
 
+  public AutoConfiguredOpenTelemetrySdkBuilder setComponentLoader(ComponentLoader componentLoader) {
+    requireNonNull(componentLoader, "componentLoader");
+    this.spiHelper = SpiHelper.create(componentLoader);
+    return this;
+  }
+
   /**
    * Returns a new {@link AutoConfiguredOpenTelemetrySdk} holding components auto-configured using
    * the settings of this {@link AutoConfiguredOpenTelemetrySdkBuilder}.
@@ -403,41 +409,53 @@ public AutoConfiguredOpenTelemetrySdk build() {
       boolean sdkEnabled = !config.getBoolean("otel.sdk.disabled", false);
 
       if (sdkEnabled) {
-        SdkMeterProviderBuilder meterProviderBuilder = SdkMeterProvider.builder();
-        meterProviderBuilder.setResource(resource);
-        MeterProviderConfiguration.configureMeterProvider(
-            meterProviderBuilder, config, spiHelper, metricExporterCustomizer, closeables);
-        meterProviderBuilder = meterProviderCustomizer.apply(meterProviderBuilder, config);
-        SdkMeterProvider meterProvider = meterProviderBuilder.build();
+        SdkMeterProvider meterProvider =
+            spiHelper.loadOptional(SdkMeterProvider.class).orElse(null);
+        if (meterProvider == null) {
+          SdkMeterProviderBuilder meterProviderBuilder = SdkMeterProvider.builder();
+          meterProviderBuilder.setResource(resource);
+          MeterProviderConfiguration.configureMeterProvider(
+              meterProviderBuilder, config, spiHelper, metricExporterCustomizer, closeables);
+          meterProviderBuilder = meterProviderCustomizer.apply(meterProviderBuilder, config);
+          meterProvider = meterProviderBuilder.build();
+        }
         closeables.add(meterProvider);
 
-        SdkTracerProviderBuilder tracerProviderBuilder = SdkTracerProvider.builder();
-        tracerProviderBuilder.setResource(resource);
-        TracerProviderConfiguration.configureTracerProvider(
-            tracerProviderBuilder,
-            config,
-            spiHelper,
-            meterProvider,
-            spanExporterCustomizer,
-            spanProcessorCustomizer,
-            samplerCustomizer,
-            closeables);
-        tracerProviderBuilder = tracerProviderCustomizer.apply(tracerProviderBuilder, config);
-        SdkTracerProvider tracerProvider = tracerProviderBuilder.build();
+        SdkTracerProvider tracerProvider =
+            spiHelper.loadOptional(SdkTracerProvider.class).orElse(null);
+        if (tracerProvider == null) {
+          SdkTracerProviderBuilder tracerProviderBuilder = SdkTracerProvider.builder();
+          tracerProviderBuilder.setResource(resource);
+          TracerProviderConfiguration.configureTracerProvider(
+              tracerProviderBuilder,
+              config,
+              spiHelper,
+              meterProvider,
+              spanExporterCustomizer,
+              spanProcessorCustomizer,
+              samplerCustomizer,
+              closeables);
+          tracerProviderBuilder = tracerProviderCustomizer.apply(tracerProviderBuilder, config);
+          tracerProvider = tracerProviderBuilder.build();
+        }
         closeables.add(tracerProvider);
 
-        SdkLoggerProviderBuilder loggerProviderBuilder = SdkLoggerProvider.builder();
-        loggerProviderBuilder.setResource(resource);
-        LoggerProviderConfiguration.configureLoggerProvider(
-            loggerProviderBuilder,
-            config,
-            spiHelper,
-            meterProvider,
-            logRecordExporterCustomizer,
-            logRecordProcessorCustomizer,
-            closeables);
-        loggerProviderBuilder = loggerProviderCustomizer.apply(loggerProviderBuilder, config);
-        SdkLoggerProvider loggerProvider = loggerProviderBuilder.build();
+        SdkLoggerProvider loggerProvider =
+            spiHelper.loadOptional(SdkLoggerProvider.class).orElse(null);
+        if (loggerProvider == null) {
+          SdkLoggerProviderBuilder loggerProviderBuilder = SdkLoggerProvider.builder();
+          loggerProviderBuilder.setResource(resource);
+          LoggerProviderConfiguration.configureLoggerProvider(
+              loggerProviderBuilder,
+              config,
+              spiHelper,
+              meterProvider,
+              logRecordExporterCustomizer,
+              logRecordProcessorCustomizer,
+              closeables);
+          loggerProviderBuilder = loggerProviderCustomizer.apply(loggerProviderBuilder, config);
+          loggerProvider = loggerProviderBuilder.build();
+        }
         closeables.add(loggerProvider);
 
         ContextPropagators propagators =

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

@@ -0,0 +1,48 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure;
+
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableProvider;
+import io.opentelemetry.sdk.autoconfigure.spi.Ordered;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+/** A loader for components that are discovered via SPI. */
+public interface ComponentLoader {
+  <T> Iterable<T> load(Class<T> spiClass);
+
+  default <T> Optional<T> loadOptional(Class<T> spiClass) {
+    Iterable<T> iterable = load(spiClass);
+    return StreamSupport.stream(iterable.spliterator(), false).findFirst();
+  }
+
+  /**
+   * Load implementations of an ordered SPI (i.e. implements {@link Ordered}).
+   *
+   * @param spiClass the SPI class
+   * @param <T> the SPI type
+   * @return list of SPI implementations, in order
+   */
+  default <T extends Ordered> List<T> loadOrdered(Class<T> spiClass) {
+    return StreamSupport.stream(load(spiClass).spliterator(), false)
+        .sorted(Comparator.comparing(Ordered::order))
+        .collect(Collectors.toList());
+  }
+
+  default <T extends ConfigurableProvider> Map<String, T> loadConfigurableProviders(
+      Class<T> spiClass) {
+    Map<String, T> components = new HashMap<>();
+    for (T component : load(spiClass)) {
+      components.put(component.getName(), component);
+    }
+    return components;
+  }
+}

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

@@ -80,7 +80,6 @@ static NamedSpiManager<LogRecordExporter> logRecordExporterSpiManager(
       ConfigProperties config, SpiHelper spiHelper) {
     return spiHelper.loadConfigurable(
         ConfigurableLogRecordExporterProvider.class,
-        ConfigurableLogRecordExporterProvider::getName,
         ConfigurableLogRecordExporterProvider::createExporter,
         config);
   }

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

@@ -19,6 +19,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.stream.Collectors;
@@ -33,20 +34,25 @@ static void configureMeterProvider(
           metricExporterCustomizer,
       List<Closeable> closeables) {
 
-    // Configure default exemplar filters.
-    String exemplarFilter =
-        config.getString("otel.metrics.exemplar.filter", "trace_based").toLowerCase(Locale.ROOT);
-    switch (exemplarFilter) {
-      case "always_off":
-        SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.alwaysOff());
-        break;
-      case "always_on":
-        SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.alwaysOn());
-        break;
-      case "trace_based":
-      default:
-        SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.traceBased());
-        break;
+    Optional<ExemplarFilter> spiExemplarFilter = spiHelper.loadOptional(ExemplarFilter.class);
+    if (spiExemplarFilter.isPresent()) {
+      SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, spiExemplarFilter.get());
+    } else {
+      // Configure default exemplar filters.
+      String exemplarFilter =
+          config.getString("otel.metrics.exemplar.filter", "trace_based").toLowerCase(Locale.ROOT);
+      switch (exemplarFilter) {
+        case "always_off":
+          SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.alwaysOff());
+          break;
+        case "always_on":
+          SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.alwaysOn());
+          break;
+        case "trace_based":
+        default:
+          SdkMeterProviderUtil.setExemplarFilter(meterProviderBuilder, ExemplarFilter.traceBased());
+          break;
+      }
     }
 
     int cardinalityLimit =

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

@@ -82,7 +82,6 @@ static NamedSpiManager<MetricReader> metricReadersSpiManager(
       ConfigProperties config, SpiHelper spiHelper) {
     return spiHelper.loadConfigurable(
         ConfigurableMetricReaderProvider.class,
-        ConfigurableMetricReaderProvider::getName,
         ConfigurableMetricReaderProvider::createMetricReader,
         config);
   }
@@ -107,7 +106,6 @@ static NamedSpiManager<MetricExporter> metricExporterSpiManager(
       ConfigProperties config, SpiHelper spiHelper) {
     return spiHelper.loadConfigurable(
         ConfigurableMetricExporterProvider.class,
-        ConfigurableMetricExporterProvider::getName,
         ConfigurableMetricExporterProvider::createExporter,
         config);
   }

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

@@ -35,7 +35,6 @@ static ContextPropagators configurePropagators(
     NamedSpiManager<TextMapPropagator> spiPropagatorsManager =
         spiHelper.loadConfigurable(
             ConfigurablePropagatorProvider.class,
-            ConfigurablePropagatorProvider::getName,
             ConfigurablePropagatorProvider::getPropagator,
             config);