Prom exporter update

exporters/prometheus/build.gradle.kts

@@ -18,6 +18,7 @@ dependencies {
   implementation("io.prometheus:prometheus-metrics-exposition-formats-no-protobuf")
 
   compileOnly("com.google.auto.value:auto-value-annotations")
+  compileOnly("com.google.errorprone:error_prone_annotations")
 
   annotationProcessor("com.google.auto.value:auto-value")
 

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverter.java

@@ -80,6 +80,8 @@ final class Otel2PrometheusConverter {
   private static final long NANOS_PER_MILLISECOND = TimeUnit.MILLISECONDS.toNanos(1);
   static final int MAX_CACHE_SIZE = 10;
 
+  private final boolean otelScopeLabelsEnabled;
+  private final boolean targetInfoMetricEnabled;
   @Nullable private final Predicate<String> allowedResourceAttributesFilter;
 
   /**
@@ -89,19 +91,40 @@ final class Otel2PrometheusConverter {
   private final Map<Attributes, List<AttributeKey<?>>> resourceAttributesToAllowedKeysCache;
 
   /**
-   * Constructor with feature flag parameter.
+   * Constructor with feature flag parameters.
    *
+   * @param otelScopeLabelsEnabled whether to add OpenTelemetry scope labels to exported metrics
+   * @param targetInfoMetricEnabled whether to export the target_info metric with resource
+   *     attributes
    * @param allowedResourceAttributesFilter if not {@code null}, resource attributes with keys
    *     matching this predicate will be added as labels on each exported metric
    */
-  Otel2PrometheusConverter(@Nullable Predicate<String> allowedResourceAttributesFilter) {
+  Otel2PrometheusConverter(
+      boolean otelScopeLabelsEnabled,
+      boolean targetInfoMetricEnabled,
+      @Nullable Predicate<String> allowedResourceAttributesFilter) {
+    this.otelScopeLabelsEnabled = otelScopeLabelsEnabled;
+    this.targetInfoMetricEnabled = targetInfoMetricEnabled;
     this.allowedResourceAttributesFilter = allowedResourceAttributesFilter;
     this.resourceAttributesToAllowedKeysCache =
         allowedResourceAttributesFilter != null
             ? new ConcurrentHashMap<>()
             : Collections.emptyMap();
   }
 
+  boolean isOtelScopeLabelsEnabled() {
+    return otelScopeLabelsEnabled;
+  }
+
+  boolean isTargetInfoMetricEnabled() {
+    return targetInfoMetricEnabled;
+  }
+
+  @Nullable
+  Predicate<String> getAllowedResourceAttributesFilter() {
+    return allowedResourceAttributesFilter;
+  }
+
   MetricSnapshots convert(@Nullable Collection<MetricData> metricDataCollection) {
     if (metricDataCollection == null || metricDataCollection.isEmpty()) {
       return MetricSnapshots.of();
@@ -118,7 +141,7 @@ MetricSnapshots convert(@Nullable Collection<MetricData> metricDataCollection) {
         resource = metricData.getResource();
       }
     }
-    if (resource != null) {
+    if (resource != null && targetInfoMetricEnabled) {
       putOrMerge(snapshotsByName, makeTargetInfo(resource));
     }
     return new MetricSnapshots(snapshotsByName.values());
@@ -457,7 +480,7 @@ private Labels convertAttributes(
           requireNonNull(additionalAttributes[i]), additionalAttributes[i + 1]);
     }
 
-    if (scope != null) {
+    if (scope != null && otelScopeLabelsEnabled) {
       labelNameToValue.putIfAbsent(OTEL_SCOPE_NAME, scope.getName());
       if (scope.getVersion() != null) {
         labelNameToValue.putIfAbsent(OTEL_SCOPE_VERSION, scope.getVersion());

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/PrometheusHttpServer.java

@@ -31,7 +31,6 @@
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
-import java.util.function.Predicate;
 import javax.annotation.Nullable;
 
 /**
@@ -42,7 +41,6 @@ public final class PrometheusHttpServer implements MetricReader {
 
   private final String host;
   private final int port;
-  @Nullable private final Predicate<String> allowedResourceAttributesFilter;
   private final MemoryMode memoryMode;
   private final DefaultAggregationSelector defaultAggregationSelector;
 
@@ -71,18 +69,17 @@ public static PrometheusHttpServerBuilder builder() {
       int port,
       @Nullable ExecutorService executor,
       PrometheusRegistry prometheusRegistry,
-      @Nullable Predicate<String> allowedResourceAttributesFilter,
       MemoryMode memoryMode,
       @Nullable HttpHandler defaultHandler,
       DefaultAggregationSelector defaultAggregationSelector,
-      @Nullable Authenticator authenticator) {
+      @Nullable Authenticator authenticator,
+      PrometheusMetricReader prometheusMetricReader) {
     this.host = host;
     this.port = port;
-    this.allowedResourceAttributesFilter = allowedResourceAttributesFilter;
     this.memoryMode = memoryMode;
     this.defaultAggregationSelector = defaultAggregationSelector;
     this.builder = builder;
-    this.prometheusMetricReader = new PrometheusMetricReader(allowedResourceAttributesFilter);
+    this.prometheusMetricReader = prometheusMetricReader;
     this.prometheusRegistry = prometheusRegistry;
     prometheusRegistry.register(prometheusMetricReader);
     // When memory mode is REUSABLE_DATA, concurrent reads lead to data corruption. To prevent this,
@@ -167,7 +164,7 @@ public String toString() {
     StringJoiner joiner = new StringJoiner(",", "PrometheusHttpServer{", "}");
     joiner.add("host=" + host);
     joiner.add("port=" + port);
-    joiner.add("allowedResourceAttributesFilter=" + allowedResourceAttributesFilter);
+    joiner.add("metricReader=" + prometheusMetricReader.toString());
     joiner.add("memoryMode=" + memoryMode);
     joiner.add(
         "defaultAggregationSelector="

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/PrometheusHttpServerBuilder.java

@@ -30,7 +30,7 @@ public final class PrometheusHttpServerBuilder {
   private String host = DEFAULT_HOST;
   private int port = DEFAULT_PORT;
   private PrometheusRegistry prometheusRegistry = new PrometheusRegistry();
-  @Nullable private Predicate<String> allowedResourceAttributesFilter;
+  private PrometheusMetricReaderBuilder metricReaderBuilder = PrometheusMetricReader.builder();
   @Nullable private ExecutorService executor;
   private MemoryMode memoryMode = DEFAULT_MEMORY_MODE;
   @Nullable private HttpHandler defaultHandler;
@@ -44,7 +44,7 @@ public final class PrometheusHttpServerBuilder {
     this.host = builder.host;
     this.port = builder.port;
     this.prometheusRegistry = builder.prometheusRegistry;
-    this.allowedResourceAttributesFilter = builder.allowedResourceAttributesFilter;
+    this.metricReaderBuilder = new PrometheusMetricReaderBuilder(builder.metricReaderBuilder);
     this.executor = builder.executor;
     this.memoryMode = builder.memoryMode;
     this.defaultAggregationSelector = builder.defaultAggregationSelector;
@@ -74,21 +74,21 @@ public PrometheusHttpServerBuilder setExecutor(ExecutorService executor) {
   }
 
   /** Sets the {@link PrometheusRegistry} to be used for {@link PrometheusHttpServer}. */
-  @SuppressWarnings("UnusedReturnValue")
   public PrometheusHttpServerBuilder setPrometheusRegistry(PrometheusRegistry prometheusRegistry) {
     requireNonNull(prometheusRegistry, "prometheusRegistry");
     this.prometheusRegistry = prometheusRegistry;
     return this;
   }
 
-  /**
-   * Set if the {@code otel_scope_*} attributes are generated. Default is {@code true}.
-   *
-   * @deprecated {@code otel_scope_*} attributes are always generated.
-   */
-  @SuppressWarnings("UnusedReturnValue")
-  @Deprecated
-  public PrometheusHttpServerBuilder setOtelScopeEnabled(boolean otelScopeEnabled) {
+  /** Set if the {@code otel_scope_*} attributes are generated. Default is {@code true}. */
+  public PrometheusHttpServerBuilder setOtelScopeLabelsEnabled(boolean otelScopeLabelsEnabled) {
+    metricReaderBuilder.setOtelScopeLabelsEnabled(otelScopeLabelsEnabled);
+    return this;
+  }
+
+  /** Set if the {@code otel_target_info} metric is generated. Default is {@code true}. */
+  public PrometheusHttpServerBuilder setTargetInfoMetricEnabled(boolean targetInfoMetricEnabled) {
+    metricReaderBuilder.setTargetInfoMetricEnabled(targetInfoMetricEnabled);
     return this;
   }
 
@@ -104,7 +104,8 @@ public PrometheusHttpServerBuilder setOtelScopeEnabled(boolean otelScopeEnabled)
    */
   public PrometheusHttpServerBuilder setAllowedResourceAttributesFilter(
       Predicate<String> resourceAttributesFilter) {
-    this.allowedResourceAttributesFilter = requireNonNull(resourceAttributesFilter);
+    requireNonNull(resourceAttributesFilter, "resourceAttributesFilter");
+    metricReaderBuilder.setAllowedResourceAttributesFilter(resourceAttributesFilter);
     return this;
   }
 
@@ -178,10 +179,10 @@ public PrometheusHttpServer build() {
         port,
         executor,
         prometheusRegistry,
-        allowedResourceAttributesFilter,
         memoryMode,
         defaultHandler,
         defaultAggregationSelector,
-        authenticator);
+        authenticator,
+        metricReaderBuilder.build());
   }
 }

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/PrometheusMetricReader.java

@@ -12,6 +12,7 @@
 import io.opentelemetry.sdk.metrics.export.MetricReader;
 import io.prometheus.metrics.model.registry.MultiCollector;
 import io.prometheus.metrics.model.snapshots.MetricSnapshots;
+import java.util.StringJoiner;
 import java.util.function.Predicate;
 import javax.annotation.Nullable;
 
@@ -28,21 +29,54 @@ public class PrometheusMetricReader implements MetricReader, MultiCollector {
   private volatile CollectionRegistration collectionRegistration = CollectionRegistration.noop();
   private final Otel2PrometheusConverter converter;
 
+  /** Returns a new {@link PrometheusMetricReader} with default configuration. */
+  public static PrometheusMetricReader create() {
+    return builder().build();
+  }
+
+  /** Returns a new {@link PrometheusMetricReaderBuilder}. */
+  public static PrometheusMetricReaderBuilder builder() {
+    return new PrometheusMetricReaderBuilder();
+  }
+
   /**
-   * Deprecated. Use {@link #PrometheusMetricReader(Predicate)}.
+   * Deprecated. Use {@link #builder()}.
    *
-   * @deprecated use {@link #PrometheusMetricReader(Predicate)}.
+   * @deprecated use {@link #builder()}.
    */
   @Deprecated
   @SuppressWarnings({"unused", "InconsistentOverloads"})
   public PrometheusMetricReader(
       boolean otelScopeEnabled, @Nullable Predicate<String> allowedResourceAttributesFilter) {
-    this.converter = new Otel2PrometheusConverter(allowedResourceAttributesFilter);
+    // otelScopeEnabled parameter was used to control the scope info metric, not scope labels.
+    this(
+        allowedResourceAttributesFilter,
+        /* otelScopeLabelsEnabled= */ true,
+        /* targetInfoMetricEnabled= */ true);
   }
 
-  // TODO: refactor to public static create or builder pattern to align with project style
+  /**
+   * Deprecated. Use {@link #builder()}.
+   *
+   * @deprecated use {@link #builder()}.
+   */
+  @Deprecated
   public PrometheusMetricReader(@Nullable Predicate<String> allowedResourceAttributesFilter) {
-    this.converter = new Otel2PrometheusConverter(allowedResourceAttributesFilter);
+    this(
+        allowedResourceAttributesFilter,
+        /* otelScopeLabelsEnabled= */ true,
+        /* targetInfoMetricEnabled= */ true);
+  }
+
+  // Package-private constructor used by builder
+  @SuppressWarnings("InconsistentOverloads")
+  PrometheusMetricReader(
+      @Nullable Predicate<String> allowedResourceAttributesFilter,
+      boolean otelScopeLabelsEnabled,
+      boolean targetInfoMetricEnabled) {
+    this.converter =
+        new Otel2PrometheusConverter(
+            otelScopeLabelsEnabled, targetInfoMetricEnabled, allowedResourceAttributesFilter);
   }
 
   @Override
@@ -69,4 +103,13 @@ public CompletableResultCode shutdown() {
   public MetricSnapshots collect() {
     return converter.convert(collectionRegistration.collectAllMetrics());
   }
+
+  @Override
+  public String toString() {
+    StringJoiner joiner = new StringJoiner(",", "PrometheusMetricReader{", "}");
+    joiner.add("otelScopeLabelsEnabled=" + converter.isOtelScopeLabelsEnabled());
+    joiner.add("targetInfoMetricEnabled=" + converter.isTargetInfoMetricEnabled());
+    joiner.add("allowedResourceAttributesFilter=" + converter.getAllowedResourceAttributesFilter());
+    return joiner.toString();
+  }
 }

exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/PrometheusMetricReaderBuilder.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.prometheus;
+
+import java.util.function.Predicate;
+import javax.annotation.Nullable;
+
+/** Builder for {@link PrometheusMetricReader}. */
+public final class PrometheusMetricReaderBuilder {
+
+  private boolean otelScopeLabelsEnabled = true;
+  private boolean targetInfoMetricEnabled = true;
+  @Nullable private Predicate<String> allowedResourceAttributesFilter;
+
+  PrometheusMetricReaderBuilder() {}
+
+  PrometheusMetricReaderBuilder(PrometheusMetricReaderBuilder metricReaderBuilder) {
+    this.otelScopeLabelsEnabled = metricReaderBuilder.otelScopeLabelsEnabled;
+    this.targetInfoMetricEnabled = metricReaderBuilder.targetInfoMetricEnabled;
+    this.allowedResourceAttributesFilter = metricReaderBuilder.allowedResourceAttributesFilter;
+  }
+
+  /**
+   * Sets whether to add OpenTelemetry scope labels (otel_scope_name, otel_scope_version, etc.) to
+   * exported metrics. Default is {@code true}.
+   *
+   * @param otelScopeLabelsEnabled whether to add scope labels
+   * @return this builder
+   */
+  public PrometheusMetricReaderBuilder setOtelScopeLabelsEnabled(boolean otelScopeLabelsEnabled) {
+    this.otelScopeLabelsEnabled = otelScopeLabelsEnabled;
+    return this;
+  }
+
+  /**
+   * Sets whether to export the target_info metric with resource attributes. Default is {@code
+   * true}.
+   *
+   * @param targetInfoMetricEnabled whether to export target_info metric
+   * @return this builder
+   */
+  public PrometheusMetricReaderBuilder setTargetInfoMetricEnabled(boolean targetInfoMetricEnabled) {
+    this.targetInfoMetricEnabled = targetInfoMetricEnabled;
+    return this;
+  }
+
+  /**
+   * Sets a filter to control which resource attributes are added as labels on each exported metric.
+   * If {@code null}, no resource attributes will be added as labels. Default is {@code null}.
+   *
+   * @param allowedResourceAttributesFilter predicate to filter resource attributes, or {@code null}
+   * @return this builder
+   */
+  public PrometheusMetricReaderBuilder setAllowedResourceAttributesFilter(
+      @Nullable Predicate<String> allowedResourceAttributesFilter) {
+    this.allowedResourceAttributesFilter = allowedResourceAttributesFilter;
+    return this;
+  }
+
+  /** Builds a new {@link PrometheusMetricReader}. */
+  public PrometheusMetricReader build() {
+    return new PrometheusMetricReader(
+        allowedResourceAttributesFilter, otelScopeLabelsEnabled, targetInfoMetricEnabled);
+  }
+}

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

@@ -45,6 +45,15 @@ public MetricReader create(DeclarativeConfigProperties config) {
       prometheusBuilder.setHost(host);
     }
 
+    Boolean withoutTargetInfo = config.getBoolean("without_target_info");
+    if (withoutTargetInfo != null) {
+      prometheusBuilder.setTargetInfoMetricEnabled(!withoutTargetInfo);
+    }
+    Boolean withoutScopeInfo = config.getBoolean("without_scope_info");
+    if (withoutScopeInfo != null) {
+      prometheusBuilder.setOtelScopeLabelsEnabled(!withoutScopeInfo);
+    }
+
     DeclarativeConfigProperties withResourceConstantLabels =
         config.getStructured("with_resource_constant_labels");
     if (withResourceConstantLabels != null) {

exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverterTest.java

@@ -71,7 +71,10 @@ class Otel2PrometheusConverterTest {
   private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
 
   private final Otel2PrometheusConverter converter =
-      new Otel2PrometheusConverter(/* allowedResourceAttributesFilter= */ null);
+      new Otel2PrometheusConverter(
+          /* otelScopeLabelsEnabled= */ true,
+          /* targetInfoMetricEnabled= */ true,
+          /* allowedResourceAttributesFilter= */ null);
 
   @ParameterizedTest
   @MethodSource("metricMetadataArgs")
@@ -201,7 +204,10 @@ void resourceAttributesAddition(
       throws IOException {
 
     Otel2PrometheusConverter converter =
-        new Otel2PrometheusConverter(allowedResourceAttributesFilter);
+        new Otel2PrometheusConverter(
+            /* otelScopeLabelsEnabled= */ true,
+            /* targetInfoMetricEnabled= */ true,
+            allowedResourceAttributesFilter);
 
     ByteArrayOutputStream out = new ByteArrayOutputStream();
     MetricSnapshots snapshots = converter.convert(Collections.singletonList(metricData));
@@ -501,7 +507,10 @@ void validateCacheIsBounded() {
         };
 
     Otel2PrometheusConverter otel2PrometheusConverter =
-        new Otel2PrometheusConverter(/* allowedResourceAttributesFilter= */ countPredicate);
+        new Otel2PrometheusConverter(
+            /* otelScopeLabelsEnabled= */ true,
+            /* targetInfoMetricEnabled= */ true,
+            /* allowedResourceAttributesFilter= */ countPredicate);
 
     // Create 20 different metric data objects with 2 different resource attributes;
     Resource resource1 = Resource.builder().put("cluster", "cluster1").build();