Define dedicated file configuration SPI ComponentProvider

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/internal/PrometheusComponentProvider.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.prometheus.internal;
+
+import io.opentelemetry.exporter.prometheus.PrometheusHttpServer;
+import io.opentelemetry.exporter.prometheus.PrometheusHttpServerBuilder;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.StructuredConfigProperties;
+import io.opentelemetry.sdk.metrics.export.MetricReader;
+
+/**
+ * File configuration SPI implementation for {@link PrometheusHttpServer}.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+public class PrometheusComponentProvider implements ComponentProvider<MetricReader> {
+
+  @Override
+  public Class<MetricReader> getType() {
+    return MetricReader.class;
+  }
+
+  @Override
+  public String getName() {
+    return "prometheus";
+  }
+
+  @Override
+  public MetricReader create(StructuredConfigProperties config) {
+    PrometheusHttpServerBuilder prometheusBuilder = PrometheusHttpServer.builder();
+
+    Integer port = config.getInt("port");
+    if (port != null) {
+      prometheusBuilder.setPort(port);
+    }
+    String host = config.getString("host");
+    if (host != null) {
+      prometheusBuilder.setHost(host);
+    }
+
+    return prometheusBuilder.build();
+  }
+}

exporters/prometheus/src/main/resources/META-INF/services/io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider

@@ -0,0 +1 @@
+io.opentelemetry.exporter.prometheus.internal.PrometheusComponentProvider

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

@@ -0,0 +1,45 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure.spi.internal;
+
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+/**
+ * Provides configured instances of SDK extension components. {@link ComponentProvider} allows SDK
+ * extension components which are not part of the core SDK to be referenced in file based
+ * configuration.
+ *
+ * @param <T> the type of the SDK extension component. See {@link #getType()}.
+ */
+// TODO (jack-berg): list the specific types which are supported in file configuration
+public interface ComponentProvider<T> {
+
+  /**
+   * The type of SDK extension component. For example, if providing instances of a custom span
+   * exporter, the type would be {@link SpanExporter}.
+   */
+  Class<T> getType();
+
+  /**
+   * The name of the exporter, to be referenced in configuration files. For example, if providing
+   * instances of a custom span exporter for the "acme" protocol, the name might be "acme".
+   *
+   * <p>This name MUST not be the same as any other component provider name which returns components
+   * of the same {@link #getType() type}.
+   */
+  String getName();
+
+  /**
+   * Configure an instance of the SDK extension component according to the {@code config}.
+   *
+   * @param config the configuration provided where the component is referenced in a configuration
+   *     file.
+   * @return an instance the SDK extension component
+   */
+  // TODO (jack-berg): consider dynamic configuration use case before stabilizing in case that
+  // affects any API decisions
+  T create(StructuredConfigProperties config);
+}

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

@@ -0,0 +1,187 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure.spi.internal;
+
+import static io.opentelemetry.api.internal.ConfigUtil.defaultIfNull;
+
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException;
+import java.util.List;
+import java.util.Set;
+import javax.annotation.Nullable;
+
+/**
+ * An interface for accessing structured configuration data.
+ *
+ * <p>An instance of {@link StructuredConfigProperties} is equivalent to a <a
+ * href="https://yaml.org/spec/1.2.2/#3211-nodes">YAML mapping node</a>. It has accessors for
+ * reading scalar properties, {@link #getStructured(String)} for reading children which are
+ * themselves mappings, and {@link #getStructuredList(String)} for reading children which are
+ * sequences of mappings.
+ */
+public interface StructuredConfigProperties {
+
+  /**
+   * Returns a {@link String} configuration property.
+   *
+   * @return null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar string
+   */
+  @Nullable
+  String getString(String name);
+
+  /**
+   * Returns a {@link String} configuration property.
+   *
+   * @return a {@link String} configuration property or {@code defaultValue} if a property with
+   *     {@code name} has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar string
+   */
+  default String getString(String name, String defaultValue) {
+    return defaultIfNull(getString(name), defaultValue);
+  }
+
+  /**
+   * Returns a {@link Boolean} configuration property. Implementations should use the same rules as
+   * {@link Boolean#parseBoolean(String)} for handling the values.
+   *
+   * @return null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar boolean
+   */
+  @Nullable
+  Boolean getBoolean(String name);
+
+  /**
+   * Returns a {@link Boolean} configuration property.
+   *
+   * @return a {@link Boolean} configuration property or {@code defaultValue} if a property with
+   *     {@code name} has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar boolean
+   */
+  default boolean getBoolean(String name, boolean defaultValue) {
+    return defaultIfNull(getBoolean(name), defaultValue);
+  }
+
+  /**
+   * Returns a {@link Integer} configuration property.
+   *
+   * <p>If the underlying config property is {@link Long}, it is converted to {@link Integer} with
+   * {@link Long#intValue()} which may result in loss of precision.
+   *
+   * @return null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar integer
+   */
+  @Nullable
+  Integer getInt(String name);
+
+  /**
+   * Returns a {@link Integer} configuration property.
+   *
+   * <p>If the underlying config property is {@link Long}, it is converted to {@link Integer} with
+   * {@link Long#intValue()} which may result in loss of precision.
+   *
+   * @return a {@link Integer} configuration property or {@code defaultValue} if a property with
+   *     {@code name} has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar integer
+   */
+  default int getInt(String name, int defaultValue) {
+    return defaultIfNull(getInt(name), defaultValue);
+  }
+
+  /**
+   * Returns a {@link Long} configuration property.
+   *
+   * @return null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar long
+   */
+  @Nullable
+  Long getLong(String name);
+
+  /**
+   * Returns a {@link Long} configuration property.
+   *
+   * @return a {@link Long} configuration property or {@code defaultValue} if a property with {@code
+   *     name} has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar long
+   */
+  default long getLong(String name, long defaultValue) {
+    return defaultIfNull(getLong(name), defaultValue);
+  }
+
+  /**
+   * Returns a {@link Double} configuration property.
+   *
+   * @return null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar double
+   */
+  @Nullable
+  Double getDouble(String name);
+
+  /**
+   * Returns a {@link Double} configuration property.
+   *
+   * @return a {@link Double} configuration property or {@code defaultValue} if a property with
+   *     {@code name} has not been configured
+   * @throws ConfigurationException if the property is not a valid scalar double
+   */
+  default double getDouble(String name, double defaultValue) {
+    return defaultIfNull(getDouble(name), defaultValue);
+  }
+
+  /**
+   * Returns a {@link List} configuration property. Empty values and values which do not map to the
+   * {@code scalarType} will be removed.
+   *
+   * @param name the property name
+   * @param scalarType the scalar type, one of {@link String}, {@link Boolean}, {@link Long} or
+   *     {@link Double}
+   * @return a {@link List} configuration property, or null if the property has not been configured
+   * @throws ConfigurationException if the property is not a valid sequence of scalars, or if {@code
+   *     scalarType} is not supported
+   */
+  @Nullable
+  <T> List<T> getScalarList(String name, Class<T> scalarType);
+
+  /**
+   * Returns a {@link List} configuration property. Entries which are not strings are converted to
+   * their string representation.
+   *
+   * @see ConfigProperties#getList(String name)
+   * @return a {@link List} configuration property or {@code defaultValue} if a property with {@code
+   *     name} has not been configured
+   * @throws ConfigurationException if the property is not a valid sequence of scalars
+   */
+  default <T> List<T> getScalarList(String name, Class<T> scalarType, List<T> defaultValue) {
+    return defaultIfNull(getScalarList(name, scalarType), defaultValue);
+  }
+
+  /**
+   * Returns a {@link StructuredConfigProperties} configuration property.
+   *
+   * @return a map-valued configuration property, or {@code null} if {@code name} has not been
+   *     configured
+   * @throws ConfigurationException if the property is not a mapping
+   */
+  @Nullable
+  StructuredConfigProperties getStructured(String name);
+
+  /**
+   * Returns a list of {@link StructuredConfigProperties} configuration property.
+   *
+   * @return a list of map-valued configuration property, or {@code null} if {@code name} has not
+   *     been configured
+   * @throws ConfigurationException if the property is not a sequence of mappings
+   */
+  @Nullable
+  List<StructuredConfigProperties> getStructuredList(String name);
+
+  /**
+   * Returns a set of all configuration property keys.
+   *
+   * @return the configuration property keys
+   */
+  Set<String> getPropertyKeys();
+}

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

@@ -10,7 +10,9 @@
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.StructuredConfigProperties;
 import io.opentelemetry.sdk.resources.Resource;
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
 /**
@@ -43,8 +45,12 @@ public static AutoConfiguredOpenTelemetrySdkBuilder builder() {
   }
 
   static AutoConfiguredOpenTelemetrySdk create(
-      OpenTelemetrySdk sdk, Resource resource, ConfigProperties config) {
-    return new AutoValue_AutoConfiguredOpenTelemetrySdk(sdk, resource, config);
+      OpenTelemetrySdk sdk,
+      Resource resource,
+      @Nullable ConfigProperties config,
+      @Nullable StructuredConfigProperties structuredConfigProperties) {
+    return new AutoValue_AutoConfiguredOpenTelemetrySdk(
+        sdk, resource, config, structuredConfigProperties);
   }
 
   /**
@@ -60,8 +66,23 @@ static AutoConfiguredOpenTelemetrySdk create(
   /** Returns the {@link Resource} that was auto-configured. */
   abstract Resource getResource();
 
-  /** Returns the {@link ConfigProperties} used for auto-configuration. */
+  /**
+   * Returns the {@link ConfigProperties} used for auto-configuration, or {@code null} if file
+   * configuration was used.
+   *
+   * @see #getStructuredConfig()
+   */
+  @Nullable
   abstract ConfigProperties getConfig();
 
+  /**
+   * Returns the {@link StructuredConfigProperties} used for auto-configuration, or {@code null} if
+   * file configuration was not used.
+   *
+   * @see #getConfig()
+   */
+  @Nullable
+  abstract StructuredConfigProperties getStructuredConfig();
+
   AutoConfiguredOpenTelemetrySdk() {}
 }

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

@@ -21,6 +21,7 @@
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.AutoConfigureListener;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.StructuredConfigProperties;
 import io.opentelemetry.sdk.logs.LogRecordProcessor;
 import io.opentelemetry.sdk.logs.SdkLoggerProvider;
 import io.opentelemetry.sdk.logs.SdkLoggerProviderBuilder;
@@ -505,7 +506,7 @@ public AutoConfiguredOpenTelemetrySdk build() {
       maybeSetAsGlobal(openTelemetrySdk);
       callAutoConfigureListeners(spiHelper, openTelemetrySdk);
 
-      return AutoConfiguredOpenTelemetrySdk.create(openTelemetrySdk, resource, config);
+      return AutoConfiguredOpenTelemetrySdk.create(openTelemetrySdk, resource, config, null);
     } catch (RuntimeException e) {
       logger.info(
           "Error encountered during autoconfiguration. Closing partially configured components.");
@@ -546,11 +547,21 @@ private static AutoConfiguredOpenTelemetrySdk maybeConfigureFromFile(ConfigPrope
     try {
       Class<?> configurationFactory =
           Class.forName("io.opentelemetry.sdk.extension.incubator.fileconfig.FileConfiguration");
-      Method parseAndCreate = configurationFactory.getMethod("parseAndCreate", InputStream.class);
-      OpenTelemetrySdk sdk = (OpenTelemetrySdk) parseAndCreate.invoke(null, fis);
+      Method parse = configurationFactory.getMethod("parse", InputStream.class);
+      Object model = parse.invoke(null, fis);
+      Class<?> openTelemetryConfiguration =
+          Class.forName(
+              "io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfiguration");
+      Method create = configurationFactory.getMethod("create", openTelemetryConfiguration);
+      OpenTelemetrySdk sdk = (OpenTelemetrySdk) create.invoke(null, model);
+      Method toConfigProperties =
+          configurationFactory.getMethod("toConfigProperties", openTelemetryConfiguration);
+      StructuredConfigProperties structuredConfigProperties =
+          (StructuredConfigProperties) toConfigProperties.invoke(null, model);
       // Note: can't access file configuration resource without reflection so setting a dummy
       // resource
-      return AutoConfiguredOpenTelemetrySdk.create(sdk, Resource.getDefault(), config);
+      return AutoConfiguredOpenTelemetrySdk.create(
+          sdk, Resource.getDefault(), null, structuredConfigProperties);
     } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException e) {
       throw new ConfigurationException(
           "Error configuring from file. Is opentelemetry-sdk-extension-incubator on the classpath?",