Promote ComponentLoader to new opentelemetry-api-util, standardize SPI loading

api/incubator/src/main/java/io/opentelemetry/api/incubator/config/DeclarativeConfigProperties.java

@@ -7,6 +7,7 @@
 
 import static io.opentelemetry.api.internal.ConfigUtil.defaultIfNull;
 
+import io.opentelemetry.context.ComponentLoader;
 import java.util.List;
 import java.util.Set;
 import javax.annotation.Nullable;
@@ -222,4 +223,7 @@ default List<DeclarativeConfigProperties> getStructuredList(
    * @return the configuration property keys
    */
   Set<String> getPropertyKeys();
+
+  /** Return a {@link ComponentLoader} that should be used to load SPIs. */
+  ComponentLoader getComponentLoader();
 }

api/incubator/src/main/java/io/opentelemetry/api/incubator/config/EmptyDeclarativeConfigProperties.java

@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.incubator.config;
 
+import io.opentelemetry.context.ComponentLoader;
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
@@ -15,6 +16,8 @@ final class EmptyDeclarativeConfigProperties implements DeclarativeConfigPropert
 
   private static final EmptyDeclarativeConfigProperties INSTANCE =
       new EmptyDeclarativeConfigProperties();
+  private static final ComponentLoader COMPONENT_LOADER =
+      ComponentLoader.forClassLoader(EmptyDeclarativeConfigProperties.class.getClassLoader());
 
   private EmptyDeclarativeConfigProperties() {}
 
@@ -74,4 +77,9 @@ public List<DeclarativeConfigProperties> getStructuredList(String name) {
   public Set<String> getPropertyKeys() {
     return Collections.emptySet();
   }
+
+  @Override
+  public ComponentLoader getComponentLoader() {
+    return COMPONENT_LOADER;
+  }
 }

context/src/main/java/io/opentelemetry/context/ComponentLoader.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.context;
+
+import java.util.ServiceLoader;
+
+/** A loader for components that are discovered via SPI. */
+public interface ComponentLoader {
+  /**
+   * Load implementations of an SPI.
+   *
+   * @param spiClass the SPI class
+   * @param <T> the SPI type
+   * @return iterable of SPI implementations
+   */
+  <T> Iterable<T> load(Class<T> spiClass);
+
+  /**
+   * Create an instance for the {@code classLoader} using {@link ServiceLoader#load(Class,
+   * ClassLoader)}.
+   */
+  static ComponentLoader forClassLoader(ClassLoader classLoader) {
+    return new ServiceLoaderComponentLoader(classLoader);
+  }
+}

context/src/main/java/io/opentelemetry/context/LazyStorage.java

@@ -39,7 +39,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.ServiceLoader;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 import java.util.logging.Level;
@@ -103,9 +102,10 @@ static ContextStorage createStorage(AtomicReference<Throwable> deferredStorageFa
       return ContextStorage.defaultStorage();
     }
 
+    ComponentLoader componentLoader =
+        ComponentLoader.forClassLoader(LazyStorage.class.getClassLoader());
     List<ContextStorageProvider> providers = new ArrayList<>();
-    for (ContextStorageProvider provider :
-        ServiceLoader.load(ContextStorageProvider.class, LazyStorage.class.getClassLoader())) {
+    for (ContextStorageProvider provider : componentLoader.load(ContextStorageProvider.class)) {
       if (provider
           .getClass()
           .getName()

context/src/main/java/io/opentelemetry/context/ServiceLoaderComponentLoader.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.context;
+
+import java.util.ServiceLoader;
+
+class ServiceLoaderComponentLoader implements ComponentLoader {
+
+  private final ClassLoader classLoader;
+
+  ServiceLoaderComponentLoader(ClassLoader classLoader) {
+    this.classLoader = classLoader;
+  }
+
+  @Override
+  public <T> Iterable<T> load(Class<T> spiClass) {
+    return ServiceLoader.load(spiClass, classLoader);
+  }
+
+  @Override
+  public String toString() {
+    return "ServiceLoaderComponentLoader{classLoader=" + classLoader + "}";
+  }
+}

docs/apidiffs/current_vs_latest/opentelemetry-context.txt

@@ -1,2 +1,7 @@
 Comparing source compatibility of opentelemetry-context-1.52.0-SNAPSHOT.jar against opentelemetry-context-1.51.0.jar
-No changes.
++++  NEW INTERFACE: PUBLIC(+) ABSTRACT(+) io.opentelemetry.context.ComponentLoader  (not serializable)
+	+++  CLASS FILE FORMAT VERSION: 52.0 <- n.a.
+	+++  NEW SUPERCLASS: java.lang.Object
+	+++  NEW METHOD: PUBLIC(+) STATIC(+) io.opentelemetry.context.ComponentLoader forClassLoader(java.lang.ClassLoader)
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) java.lang.Iterable<T> load(java.lang.Class<T>)
+		GENERIC TEMPLATES: +++ T:java.lang.Object

docs/apidiffs/current_vs_latest/opentelemetry-exporter-otlp.txt

@@ -1,2 +1,19 @@
 Comparing source compatibility of opentelemetry-exporter-otlp-1.52.0-SNAPSHOT.jar against opentelemetry-exporter-otlp-1.51.0.jar
-No changes.
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.http.logs.OtlpHttpLogRecordExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.http.logs.OtlpHttpLogRecordExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.http.metrics.OtlpHttpMetricExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.http.metrics.OtlpHttpMetricExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.logs.OtlpGrpcLogRecordExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.logs.OtlpGrpcLogRecordExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.metrics.OtlpGrpcMetricExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.metrics.OtlpGrpcMetricExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporterBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporterBuilder setComponentLoader(io.opentelemetry.context.ComponentLoader)

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

@@ -1,2 +1,4 @@
 Comparing source compatibility of opentelemetry-sdk-extension-autoconfigure-spi-1.52.0-SNAPSHOT.jar against opentelemetry-sdk-extension-autoconfigure-spi-1.51.0.jar
-No changes.
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.context.ComponentLoader getComponentLoader()

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

@@ -1,2 +1,4 @@
 Comparing source compatibility of opentelemetry-sdk-extension-autoconfigure-1.52.0-SNAPSHOT.jar against opentelemetry-sdk-extension-autoconfigure-1.51.0.jar
-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.context.ComponentLoader)

exporters/common/src/main/java/io/opentelemetry/exporter/internal/compression/CompressorUtil.java

@@ -8,9 +8,9 @@
 import static io.opentelemetry.api.internal.Utils.checkArgument;
 import static java.util.stream.Collectors.joining;
 
+import io.opentelemetry.context.ComponentLoader;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.ServiceLoader;
 import java.util.Set;
 import javax.annotation.Nullable;
 
@@ -48,7 +48,8 @@ public static Compressor validateAndResolveCompressor(String compressionMethod)
   private static Map<String, Compressor> buildCompressorRegistry() {
     Map<String, Compressor> compressors = new HashMap<>();
     for (CompressorProvider spi :
-        ServiceLoader.load(CompressorProvider.class, CompressorUtil.class.getClassLoader())) {
+        ComponentLoader.forClassLoader(CompressorUtil.class.getClassLoader())
+            .load(CompressorProvider.class)) {
       Compressor compressor = spi.getInstance();
       compressors.put(compressor.getEncoding(), compressor);
     }

exporters/common/src/main/java/io/opentelemetry/exporter/internal/grpc/GrpcExporterBuilder.java

@@ -10,6 +10,7 @@
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.internal.ConfigUtil;
 import io.opentelemetry.api.metrics.MeterProvider;
+import io.opentelemetry.context.ComponentLoader;
 import io.opentelemetry.exporter.internal.ExporterBuilderUtil;
 import io.opentelemetry.exporter.internal.TlsConfigHelper;
 import io.opentelemetry.exporter.internal.compression.Compressor;
@@ -26,7 +27,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.ServiceLoader;
 import java.util.StringJoiner;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -67,7 +67,8 @@ public class GrpcExporterBuilder<T extends Marshaler> {
   private Supplier<MeterProvider> meterProviderSupplier = GlobalOpenTelemetry::getMeterProvider;
   private InternalTelemetryVersion internalTelemetryVersion = InternalTelemetryVersion.LEGACY;
 
-  private ClassLoader serviceClassLoader = GrpcExporterBuilder.class.getClassLoader();
+  private ComponentLoader componentLoader =
+      ComponentLoader.forClassLoader(GrpcExporterBuilder.class.getClassLoader());
   @Nullable private ExecutorService executorService;
 
   // Use Object type since gRPC may not be on the classpath.
@@ -158,8 +159,8 @@ public GrpcExporterBuilder<T> setInternalTelemetryVersion(
     return this;
   }
 
-  public GrpcExporterBuilder<T> setServiceClassLoader(ClassLoader servieClassLoader) {
-    this.serviceClassLoader = servieClassLoader;
+  public GrpcExporterBuilder<T> setComponentLoader(ComponentLoader componentLoader) {
+    this.componentLoader = componentLoader;
     return this;
   }
 
@@ -268,7 +269,7 @@ public String toString(boolean includePrefixAndSuffix) {
     if (grpcChannel != null) {
       joiner.add("grpcChannel=" + grpcChannel);
     }
-    joiner.add("serviceClassLoader=" + serviceClassLoader);
+    joiner.add("componentLoader=" + componentLoader);
     if (executorService != null) {
       joiner.add("executorService=" + executorService);
     }
@@ -302,8 +303,7 @@ public String toString() {
    */
   private GrpcSenderProvider resolveGrpcSenderProvider() {
     Map<String, GrpcSenderProvider> grpcSenderProviders = new HashMap<>();
-    for (GrpcSenderProvider spi :
-        ServiceLoader.load(GrpcSenderProvider.class, serviceClassLoader)) {
+    for (GrpcSenderProvider spi : componentLoader.load(GrpcSenderProvider.class)) {
       grpcSenderProviders.put(spi.getClass().getName(), spi);
     }
 

exporters/common/src/main/java/io/opentelemetry/exporter/internal/http/HttpExporterBuilder.java

@@ -8,6 +8,7 @@
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.internal.ConfigUtil;
 import io.opentelemetry.api.metrics.MeterProvider;
+import io.opentelemetry.context.ComponentLoader;
 import io.opentelemetry.exporter.internal.ExporterBuilderUtil;
 import io.opentelemetry.exporter.internal.TlsConfigHelper;
 import io.opentelemetry.exporter.internal.compression.Compressor;
@@ -24,7 +25,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.ServiceLoader;
 import java.util.StringJoiner;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -64,7 +64,8 @@ public final class HttpExporterBuilder<T extends Marshaler> {
   @Nullable private RetryPolicy retryPolicy = RetryPolicy.getDefault();
   private Supplier<MeterProvider> meterProviderSupplier = GlobalOpenTelemetry::getMeterProvider;
   private InternalTelemetryVersion internalTelemetryVersion = InternalTelemetryVersion.LEGACY;
-  private ClassLoader serviceClassLoader = HttpExporterBuilder.class.getClassLoader();
+  private ComponentLoader componentLoader =
+      ComponentLoader.forClassLoader(HttpExporterBuilder.class.getClassLoader());
   @Nullable private ExecutorService executorService;
 
   public HttpExporterBuilder(
@@ -143,8 +144,8 @@ public HttpExporterBuilder<T> setProxyOptions(ProxyOptions proxyOptions) {
     return this;
   }
 
-  public HttpExporterBuilder<T> setServiceClassLoader(ClassLoader servieClassLoader) {
-    this.serviceClassLoader = servieClassLoader;
+  public HttpExporterBuilder<T> setComponentLoader(ComponentLoader componentLoader) {
+    this.componentLoader = componentLoader;
     return this;
   }
 
@@ -265,7 +266,7 @@ public String toString(boolean includePrefixAndSuffix) {
     if (retryPolicy != null) {
       joiner.add("retryPolicy=" + retryPolicy);
     }
-    joiner.add("serviceClassLoader=" + serviceClassLoader);
+    joiner.add("componentLoader=" + componentLoader);
     if (executorService != null) {
       joiner.add("executorService=" + executorService);
     }
@@ -299,8 +300,7 @@ public String toString() {
    */
   private HttpSenderProvider resolveHttpSenderProvider() {
     Map<String, HttpSenderProvider> httpSenderProviders = new HashMap<>();
-    for (HttpSenderProvider spi :
-        ServiceLoader.load(HttpSenderProvider.class, serviceClassLoader)) {
+    for (HttpSenderProvider spi : componentLoader.load(HttpSenderProvider.class)) {
       httpSenderProviders.put(spi.getClass().getName(), spi);
     }
 

exporters/logging-otlp/src/test/java/io/opentelemetry/exporter/logging/otlp/AbstractOtlpStdoutExporterTest.java

@@ -9,11 +9,10 @@
 import static java.util.Collections.singletonMap;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Streams;
 import io.github.netmikey.logunit.api.LogCapturer;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
@@ -29,10 +28,10 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.ServiceLoader;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 import javax.annotation.Nullable;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
@@ -306,7 +305,7 @@ void providerConfig() {
 
   @Test
   void componentProviderConfig() {
-    DeclarativeConfigProperties properties = mock(DeclarativeConfigProperties.class);
+    DeclarativeConfigProperties properties = spy(DeclarativeConfigProperties.empty());
     T exporter = exporterFromComponentProvider(properties);
 
     assertThat(exporter).extracting("wrapperJsonObject").isEqualTo(true);
@@ -330,22 +329,22 @@ void componentProviderConfig() {
   @SuppressWarnings("unchecked")
   protected T exporterFromComponentProvider(DeclarativeConfigProperties properties) {
     return (T)
-        ((ComponentProvider<?>)
-                loadSpi(ComponentProvider.class)
-                    .filter(
-                        p -> {
-                          ComponentProvider<?> c = (ComponentProvider<?>) p;
-                          return "otlp_file/development".equals(c.getName())
-                              && c.getType().equals(componentProviderType);
-                        })
-                    .findFirst()
-                    .orElseThrow(() -> new IllegalStateException("No provider found")))
+        StreamSupport.stream(
+                properties.getComponentLoader().load(ComponentProvider.class).spliterator(), false)
+            .filter(
+                p -> {
+                  ComponentProvider<?> c = p;
+                  return "otlp_file/development".equals(c.getName())
+                      && c.getType().equals(componentProviderType);
+                })
+            .findFirst()
+            .orElseThrow(() -> new IllegalStateException("No provider found"))
             .create(properties);
   }
 
   @SuppressWarnings("unchecked")
   protected T exporterFromProvider(ConfigProperties config) {
-    Object provider = loadProvider();
+    Object provider = loadProvider(config);
 
     try {
       return (T)
@@ -358,8 +357,9 @@ protected T exporterFromProvider(ConfigProperties config) {
     }
   }
 
-  private Object loadProvider() {
-    return loadSpi(providerClass)
+  private Object loadProvider(ConfigProperties config) {
+    return StreamSupport.stream(
+            config.getComponentLoader().load(providerClass).spliterator(), false)
         .filter(
             p -> {
               try {
@@ -372,8 +372,4 @@ private Object loadProvider() {
         .findFirst()
         .orElseThrow(() -> new IllegalStateException("No provider found"));
   }
-
-  protected static Stream<?> loadSpi(Class<?> type) {
-    return Streams.stream(ServiceLoader.load(type, type.getClassLoader()).iterator());
-  }
 }