Polish 'Support Per-meter configuration for OtlpMetricsProperties'

See gh-45203

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsProperties.java

@@ -58,11 +58,6 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 	 */
 	private HistogramFlavor histogramFlavor = HistogramFlavor.EXPLICIT_BUCKET_HISTOGRAM;
 
-	/**
-	 * Per meter histogram type to be preferred when histogram publishing is enabled.
-	 */
-	private Map<String, HistogramFlavor> histogramFlavorPerMeter = new LinkedHashMap<>();
-
 	/**
 	 * Max scale to use for exponential histograms, if configured.
 	 */
@@ -75,15 +70,14 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 	private int maxBucketCount = 160;
 
 	/**
-	 * Per meter number of max buckets used for exponential histograms, if configured.
-	 * This has no effect on explicit bucket histograms.
+	 * Time unit for exported metrics.
 	 */
-	private Map<String, Integer> maxBucketsPerMeter = new LinkedHashMap<>();
+	private TimeUnit baseTimeUnit = TimeUnit.MILLISECONDS;
 
 	/**
-	 * Time unit for exported metrics.
+	 * Per-meter properties that can be used to override defaults.
 	 */
-	private TimeUnit baseTimeUnit = TimeUnit.MILLISECONDS;
+	private Map<String, Meter> meter = new LinkedHashMap<>();
 
 	public String getUrl() {
 		return this.url;
@@ -117,14 +111,6 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 		this.histogramFlavor = histogramFlavor;
 	}
 
-	public Map<String, HistogramFlavor> getHistogramFlavorPerMeter() {
-		return this.histogramFlavorPerMeter;
-	}
-
-	public void setHistogramFlavorPerMeter(Map<String, HistogramFlavor> histogramFlavorPerMeter) {
-		this.histogramFlavorPerMeter = histogramFlavorPerMeter;
-	}
-
 	public int getMaxScale() {
 		return this.maxScale;
 	}
@@ -141,14 +127,6 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 		this.maxBucketCount = maxBucketCount;
 	}
 
-	public Map<String, Integer> getMaxBucketsPerMeter() {
-		return this.maxBucketsPerMeter;
-	}
-
-	public void setMaxBucketsPerMeter(Map<String, Integer> maxBucketsPerMeter) {
-		this.maxBucketsPerMeter = maxBucketsPerMeter;
-	}
-
 	public TimeUnit getBaseTimeUnit() {
 		return this.baseTimeUnit;
 	}
@@ -157,4 +135,42 @@ public class OtlpMetricsProperties extends StepRegistryProperties {
 		this.baseTimeUnit = baseTimeUnit;
 	}
 
+	public Map<String, Meter> getMeter() {
+		return this.meter;
+	}
+
+	/**
+	 * Per-meter settings.
+	 */
+	public static class Meter {
+
+		/**
+		 * Maximum number of buckets to be used for exponential histograms, if configured.
+		 * This has no effect on explicit bucket histograms.
+		 */
+		private Integer maxBucketCount;
+
+		/**
+		 * Histogram type when histogram publishing is enabled.
+		 */
+		private HistogramFlavor histogramFlavor;
+
+		public Integer getMaxBucketCount() {
+			return this.maxBucketCount;
+		}
+
+		public void setMaxBucketCount(Integer maxBucketCount) {
+			this.maxBucketCount = maxBucketCount;
+		}
+
+		public HistogramFlavor getHistogramFlavor() {
+			return this.histogramFlavor;
+		}
+
+		public void setHistogramFlavor(HistogramFlavor histogramFlavor) {
+			this.histogramFlavor = histogramFlavor;
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsPropertiesConfigAdapter.java

@@ -20,15 +20,18 @@ import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
 
 import io.micrometer.registry.otlp.AggregationTemporality;
 import io.micrometer.registry.otlp.HistogramFlavor;
 import io.micrometer.registry.otlp.OtlpConfig;
 
+import org.springframework.boot.actuate.autoconfigure.metrics.export.otlp.OtlpMetricsProperties.Meter;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.properties.StepRegistryPropertiesConfigAdapter;
 import org.springframework.boot.actuate.autoconfigure.opentelemetry.OpenTelemetryProperties;
 import org.springframework.boot.actuate.autoconfigure.opentelemetry.OpenTelemetryResourceAttributes;
 import org.springframework.core.env.Environment;
+import org.springframework.util.CollectionUtils;
 
 /**
  * Adapter to convert {@link OtlpMetricsProperties} to an {@link OtlpConfig}.
@@ -90,12 +93,12 @@ class OtlpMetricsPropertiesConfigAdapter extends StepRegistryPropertiesConfigAda
 
 	@Override
 	public Map<String, HistogramFlavor> histogramFlavorPerMeter() {
-		return get(OtlpMetricsProperties::getHistogramFlavorPerMeter, OtlpConfig.super::histogramFlavorPerMeter);
+		return get(perMeter(Meter::getHistogramFlavor), OtlpConfig.super::histogramFlavorPerMeter);
 	}
 
 	@Override
 	public Map<String, Integer> maxBucketsPerMeter() {
-		return get(OtlpMetricsProperties::getMaxBucketsPerMeter, OtlpConfig.super::maxBucketsPerMeter);
+		return get(perMeter(Meter::getMaxBucketCount), OtlpConfig.super::maxBucketsPerMeter);
 	}
 
 	@Override
@@ -113,4 +116,21 @@ class OtlpMetricsPropertiesConfigAdapter extends StepRegistryPropertiesConfigAda
 		return get(OtlpMetricsProperties::getBaseTimeUnit, OtlpConfig.super::baseTimeUnit);
 	}
 
+	private <V> Function<OtlpMetricsProperties, Map<String, V>> perMeter(Function<Meter, V> getter) {
+		return (properties) -> {
+			if (CollectionUtils.isEmpty(properties.getMeter())) {
+				return null;
+			}
+			Map<String, V> perMeter = new LinkedHashMap<>();
+			properties.getMeter().forEach((key, meterProperties) -> {
+				V value = getter.apply(meterProperties);
+				if (value != null) {
+					perMeter.put(key, value);
+				}
+			});
+			return (!perMeter.isEmpty()) ? perMeter : null;
+		};
+
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsPropertiesConfigAdapterTests.java

@@ -25,6 +25,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.export.otlp.OtlpMetricsExportAutoConfiguration.PropertiesOtlpMetricsConnectionDetails;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.otlp.OtlpMetricsProperties.Meter;
 import org.springframework.boot.actuate.autoconfigure.opentelemetry.OpenTelemetryProperties;
 import org.springframework.mock.env.MockEnvironment;
 
@@ -117,8 +118,9 @@ class OtlpMetricsPropertiesConfigAdapterTests {
 
 	@Test
 	void whenPropertiesHistogramFlavorPerMeterIsSetAdapterHistogramFlavorPerMeterReturnsIt() {
-		this.properties
-			.setHistogramFlavorPerMeter(Map.of("my.histograms", HistogramFlavor.BASE2_EXPONENTIAL_BUCKET_HISTOGRAM));
+		Meter meterProperties = new Meter();
+		meterProperties.setHistogramFlavor(HistogramFlavor.BASE2_EXPONENTIAL_BUCKET_HISTOGRAM);
+		this.properties.getMeter().put("my.histograms", meterProperties);
 		assertThat(createAdapter().histogramFlavorPerMeter()).containsEntry("my.histograms",
 				HistogramFlavor.BASE2_EXPONENTIAL_BUCKET_HISTOGRAM);
 	}
@@ -152,7 +154,9 @@ class OtlpMetricsPropertiesConfigAdapterTests {
 
 	@Test
 	void whenPropertiesMaxBucketsPerMeterIsSetAdapterMaxBucketsPerMeterReturnsIt() {
-		this.properties.setMaxBucketsPerMeter(Map.of("my.histograms", 111));
+		Meter meterProperties = new Meter();
+		meterProperties.setMaxBucketCount(111);
+		this.properties.getMeter().put("my.histograms", meterProperties);
 		assertThat(createAdapter().maxBucketsPerMeter()).containsEntry("my.histograms", 111);
 	}
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsPropertiesTests.java

@@ -37,11 +37,10 @@ class OtlpMetricsPropertiesTests extends StepRegistryPropertiesTests {
 		assertStepRegistryDefaultValues(properties, config);
 		assertThat(properties.getAggregationTemporality()).isSameAs(config.aggregationTemporality());
 		assertThat(properties.getHistogramFlavor()).isSameAs(config.histogramFlavor());
-		assertThat(properties.getHistogramFlavorPerMeter()).isEqualTo(config.histogramFlavorPerMeter());
 		assertThat(properties.getMaxScale()).isEqualTo(config.maxScale());
 		assertThat(properties.getMaxBucketCount()).isEqualTo(config.maxBucketCount());
-		assertThat(properties.getMaxBucketsPerMeter()).isEqualTo(config.maxBucketsPerMeter());
 		assertThat(properties.getBaseTimeUnit()).isSameAs(config.baseTimeUnit());
+		assertThat(properties.getMeter()).isEmpty();
 	}
 
 }

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -1548,7 +1548,7 @@ bom {
 			releaseNotes("https://github.com/apache/maven-war-plugin/releases/tag/maven-war-plugin-{version}")
 		}
 	}
-	library("Micrometer", "1.15.0-RC1") {
+	library("Micrometer", "1.15.0-SNAPSHOT") {
 		considerSnapshots()
 		group("io.micrometer") {
 			modules = [