Polish "Auto-config support for latest Prometheus client and simpleclient"

See gh-40023

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

@@ -58,31 +58,31 @@ public class PrometheusMetricsExportAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public PrometheusConfig prometheusConfig(PrometheusProperties prometheusProperties) {
+	PrometheusConfig prometheusConfig(PrometheusProperties prometheusProperties) {
 		return new PrometheusPropertiesConfigAdapter(prometheusProperties);
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
-	public PrometheusMeterRegistry prometheusMeterRegistry(PrometheusConfig prometheusConfig,
+	PrometheusMeterRegistry prometheusMeterRegistry(PrometheusConfig prometheusConfig,
 			PrometheusRegistry prometheusRegistry, Clock clock, ObjectProvider<SpanContext> spanContext) {
 		return new PrometheusMeterRegistry(prometheusConfig, prometheusRegistry, clock, spanContext.getIfAvailable());
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
-	public PrometheusRegistry prometheusRegistry() {
+	PrometheusRegistry prometheusRegistry() {
 		return new PrometheusRegistry();
 	}
 
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnAvailableEndpoint(endpoint = PrometheusScrapeEndpoint.class)
-	public static class PrometheusScrapeEndpointConfiguration {
+	static class PrometheusScrapeEndpointConfiguration {
 
 		@SuppressWarnings("removal")
 		@Bean
 		@ConditionalOnMissingBean({ PrometheusScrapeEndpoint.class, PrometheusSimpleclientScrapeEndpoint.class })
-		public PrometheusScrapeEndpoint prometheusEndpoint(PrometheusRegistry prometheusRegistry) {
+		PrometheusScrapeEndpoint prometheusEndpoint(PrometheusRegistry prometheusRegistry) {
 			return new PrometheusScrapeEndpoint(prometheusRegistry);
 		}
 

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

@@ -22,6 +22,7 @@ import java.util.Map;
 
 import org.springframework.boot.actuate.metrics.export.prometheus.PrometheusPushGatewayManager.ShutdownOperation;
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.DeprecatedConfigurationProperty;
 
 /**
  * {@link ConfigurationProperties @ConfigurationProperties} for configuring metrics export
@@ -54,13 +55,13 @@ public class PrometheusProperties {
 	/**
 	 * Histogram type for backing DistributionSummary and Timer.
 	 */
-	@Deprecated(since = "3.3.0")
+	@Deprecated(since = "3.3.0", forRemoval = true)
 	private HistogramFlavor histogramFlavor = HistogramFlavor.Prometheus;
 
 	/**
 	 * Additional properties to pass to the Prometheus client.
 	 */
-	private final Map<String, String> prometheusProperties = new HashMap<>();
+	private final Map<String, String> properties = new HashMap<>();
 
 	/**
 	 * Step size (i.e. reporting frequency) to use.
@@ -75,6 +76,9 @@ public class PrometheusProperties {
 		this.descriptions = descriptions;
 	}
 
+	@Deprecated(since = "3.3.0", forRemoval = true)
+	@DeprecatedConfigurationProperty(since = "3.3.0",
+			reason = "No longer supported. Works only when using the Prometheus simpleclient.")
 	public HistogramFlavor getHistogramFlavor() {
 		return this.histogramFlavor;
 	}
@@ -103,8 +107,8 @@ public class PrometheusProperties {
 		return this.pushgateway;
 	}
 
-	public Map<String, String> getPrometheusProperties() {
-		return this.prometheusProperties;
+	public Map<String, String> getProperties() {
+		return this.properties;
 	}
 
 	/**
@@ -218,13 +222,16 @@ public class PrometheusProperties {
 
 	}
 
+	/**
+	 * Prometheus Histogram flavor.
+	 *
+	 * @deprecated since 3.3.0 for removal in 3.5.0
+	 */
+	@Deprecated(since = "3.3.0", forRemoval = true)
 	public enum HistogramFlavor {
 
 		Prometheus, VictoriaMetrics;
 
-		HistogramFlavor() {
-		}
-
 	}
 
 }

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

@@ -63,7 +63,7 @@ class PrometheusPropertiesConfigAdapter extends PropertiesConfigAdapter<Promethe
 	}
 
 	private Properties fromPropertiesMap(PrometheusProperties prometheusProperties) {
-		Map<String, String> map = prometheusProperties.getPrometheusProperties();
+		Map<String, String> map = prometheusProperties.getProperties();
 		if (map.isEmpty()) {
 			return null;
 		}

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

@@ -61,9 +61,9 @@ import org.springframework.util.StringUtils;
  * @author David J. M. Karlsen
  * @author Jonatan Ivanov
  * @since 2.0.0
- * @deprecated in favor of {@link PrometheusMetricsExportAutoConfiguration}
+ * @deprecated since 3.3.0 for removal in 3.5.0 in favor of
+ * {@link PrometheusMetricsExportAutoConfiguration}
  */
-@SuppressWarnings("removal")
 @Deprecated(since = "3.3.0", forRemoval = true)
 @AutoConfiguration(
 		before = { CompositeMeterRegistryAutoConfiguration.class, SimpleMetricsExportAutoConfiguration.class },
@@ -76,13 +76,13 @@ public class PrometheusSimpleclientMetricsExportAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public PrometheusConfig simpleclientPrometheusConfig(PrometheusProperties prometheusProperties) {
+	PrometheusConfig simpleclientPrometheusConfig(PrometheusProperties prometheusProperties) {
 		return new PrometheusSimpleclientPropertiesConfigAdapter(prometheusProperties);
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
-	public io.micrometer.prometheus.PrometheusMeterRegistry simpleclientPrometheusMeterRegistry(
+	io.micrometer.prometheus.PrometheusMeterRegistry simpleclientPrometheusMeterRegistry(
 			io.micrometer.prometheus.PrometheusConfig prometheusConfig, CollectorRegistry collectorRegistry,
 			Clock clock, ObjectProvider<ExemplarSampler> exemplarSamplerProvider) {
 		return new io.micrometer.prometheus.PrometheusMeterRegistry(prometheusConfig, collectorRegistry, clock,
@@ -91,25 +91,25 @@ public class PrometheusSimpleclientMetricsExportAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public CollectorRegistry collectorRegistry() {
+	CollectorRegistry collectorRegistry() {
 		return new CollectorRegistry(true);
 	}
 
 	@Bean
 	@ConditionalOnMissingBean(ExemplarSampler.class)
 	@ConditionalOnBean(SpanContextSupplier.class)
-	public DefaultExemplarSampler exemplarSampler(SpanContextSupplier spanContextSupplier) {
+	DefaultExemplarSampler exemplarSampler(SpanContextSupplier spanContextSupplier) {
 		return new DefaultExemplarSampler(spanContextSupplier);
 	}
 
 	@SuppressWarnings("removal")
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnAvailableEndpoint(endpoint = PrometheusSimpleclientScrapeEndpoint.class)
-	public static class PrometheusScrapeEndpointConfiguration {
+	static class PrometheusScrapeEndpointConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean({ PrometheusSimpleclientScrapeEndpoint.class, PrometheusScrapeEndpoint.class })
-		public PrometheusSimpleclientScrapeEndpoint prometheusEndpoint(CollectorRegistry collectorRegistry) {
+		PrometheusSimpleclientScrapeEndpoint prometheusEndpoint(CollectorRegistry collectorRegistry) {
 			return new PrometheusSimpleclientScrapeEndpoint(collectorRegistry);
 		}
 
@@ -122,7 +122,7 @@ public class PrometheusSimpleclientMetricsExportAutoConfiguration {
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnClass(PushGateway.class)
 	@ConditionalOnProperty(prefix = "management.prometheus.metrics.export.pushgateway", name = "enabled")
-	public static class PrometheusPushGatewayConfiguration {
+	static class PrometheusPushGatewayConfiguration {
 
 		/**
 		 * The fallback job name. We use 'spring' since there's a history of Prometheus
@@ -133,7 +133,7 @@ public class PrometheusSimpleclientMetricsExportAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean
-		public PrometheusPushGatewayManager prometheusPushGatewayManager(CollectorRegistry collectorRegistry,
+		PrometheusPushGatewayManager prometheusPushGatewayManager(CollectorRegistry collectorRegistry,
 				PrometheusProperties prometheusProperties, Environment environment) throws MalformedURLException {
 			PrometheusProperties.Pushgateway properties = prometheusProperties.getPushgateway();
 			Duration pushRate = properties.getPushRate();

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

@@ -18,7 +18,6 @@ package org.springframework.boot.actuate.autoconfigure.metrics.export.prometheus
 
 import java.time.Duration;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.prometheus.PrometheusProperties.HistogramFlavor;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.properties.PropertiesConfigAdapter;
 
 /**
@@ -58,8 +57,7 @@ class PrometheusSimpleclientPropertiesConfigAdapter extends PropertiesConfigAdap
 	}
 
 	static io.micrometer.prometheus.HistogramFlavor mapToMicrometerHistogramFlavor(PrometheusProperties properties) {
-		HistogramFlavor histogramFlavor = properties.getHistogramFlavor();
-		return switch (histogramFlavor) {
+		return switch (properties.getHistogramFlavor()) {
 			case Prometheus -> io.micrometer.prometheus.HistogramFlavor.Prometheus;
 			case VictoriaMetrics -> io.micrometer.prometheus.HistogramFlavor.VictoriaMetrics;
 		};

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/prometheus/PrometheusSimpleclientExemplarsAutoConfiguration.java

@@ -37,6 +37,7 @@ import org.springframework.util.function.SingletonSupplier;
  *
  * @author Jonatan Ivanov
  * @since 3.0.0
+ * @deprecated since 3.3.0 for removal in 3.5.0
  */
 @SuppressWarnings("removal")
 @Deprecated(forRemoval = true, since = "3.3.0")

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

@@ -30,7 +30,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Mirko Sobeck
  */
-@SuppressWarnings({ "deprecation" })
+@SuppressWarnings({ "deprecation", "removal" })
 class PrometheusSimpleclientPropertiesConfigAdapterTests extends
 		AbstractPropertiesConfigAdapterTests<PrometheusProperties, PrometheusSimpleclientPropertiesConfigAdapter> {
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/prometheus/PrometheusExemplarsAutoConfigurationTests.java

@@ -86,7 +86,7 @@ class PrometheusExemplarsAutoConfigurationTests {
 	@Test
 	void prometheusOpenMetricsOutputWithoutExemplarsOnHistogramCount() {
 		this.contextRunner.withPropertyValues(
-				"management.prometheus.metrics.export.prometheus-properties.io.prometheus.exporter.exemplarsOnAllMetricTypes=false")
+				"management.prometheus.metrics.export.properties.io.prometheus.exporter.exemplarsOnAllMetricTypes=false")
 			.run((context) -> {
 				assertThat(context).hasSingleBean(SpanContext.class);
 				ObservationRegistry observationRegistry = context.getBean(ObservationRegistry.class);

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/prometheus/PrometheusScrapeEndpoint.java

@@ -35,6 +35,7 @@ import org.springframework.lang.Nullable;
  *
  * @author Jon Schneider
  * @author Johnny Lim
+ * @author Moritz Halbritter
  * @since 2.0.0
  */
 @WebEndpoint(id = "prometheus")
@@ -51,17 +52,15 @@ public class PrometheusScrapeEndpoint {
 	}
 
 	@ReadOperation(producesFrom = PrometheusOutputFormat.class)
-	public WebEndpointResponse<String> scrape(PrometheusOutputFormat format, @Nullable Set<String> includedNames) {
+	public WebEndpointResponse<byte[]> scrape(PrometheusOutputFormat format, @Nullable Set<String> includedNames) {
 		try {
 			ByteArrayOutputStream outputStream = new ByteArrayOutputStream(this.nextMetricsScrapeSize);
 			MetricSnapshots metricSnapshots = (includedNames != null)
 					? this.prometheusRegistry.scrape(includedNames::contains) : this.prometheusRegistry.scrape();
 			format.write(outputStream, metricSnapshots);
-
-			String scrapePage = outputStream.toString();
-			this.nextMetricsScrapeSize = scrapePage.length() + METRICS_SCRAPE_CHARS_EXTRA;
-
-			return new WebEndpointResponse<>(scrapePage, format);
+			byte[] content = outputStream.toByteArray();
+			this.nextMetricsScrapeSize = content.length + METRICS_SCRAPE_CHARS_EXTRA;
+			return new WebEndpointResponse<>(content, format);
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException("Writing metrics failed", ex);

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/prometheus/PrometheusSimpleclientScrapeEndpoint.java

@@ -38,7 +38,8 @@ import org.springframework.lang.Nullable;
  * @author Jon Schneider
  * @author Johnny Lim
  * @since 2.0.0
- * @deprecated in favor of {@link PrometheusScrapeEndpoint}
+ * @deprecated since 3.3.0 for removal in 3.5.0 in favor of
+ * {@link PrometheusScrapeEndpoint}
  */
 @Deprecated(since = "3.3.0", forRemoval = true)
 @WebEndpoint(id = "prometheus")
@@ -63,10 +64,8 @@ public class PrometheusSimpleclientScrapeEndpoint {
 					? this.collectorRegistry.filteredMetricFamilySamples(includedNames)
 					: this.collectorRegistry.metricFamilySamples();
 			format.write(writer, samples);
-
 			String scrapePage = writer.toString();
 			this.nextMetricsScrapeSize = scrapePage.length() + METRICS_SCRAPE_CHARS_EXTRA;
-
 			return new WebEndpointResponse<>(scrapePage, format);
 		}
 		catch (IOException ex) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/prometheus/TextOutputFormat.java

@@ -32,7 +32,7 @@ import org.springframework.util.MimeTypeUtils;
  *
  * @author Andy Wilkinson
  * @since 2.5.0
- * @deprecated in favor of {@link PrometheusOutputFormat}
+ * @deprecated since 3.3.0 for removal in 3.5.0 in favor of {@link PrometheusOutputFormat}
  */
 @Deprecated(since = "3.3.0", forRemoval = true)
 public enum TextOutputFormat implements Producible<TextOutputFormat> {

spring-boot-project/spring-boot-docs/src/docs/antora/modules/reference/pages/actuator/metrics.adoc

@@ -543,11 +543,13 @@ scrape_configs:
 ----
 
 https://prometheus.io/docs/prometheus/latest/feature_flags/#exemplars-storage[Prometheus Exemplars] are also supported.
-To enable this feature, a `SpanContextSupplier` bean should be present.
+To enable this feature, a `SpanContext` bean should be present.
+If you're using the deprecated Prometheus simpleclient support and want to enable that feature, a `SpanContextSupplier` bean should be present.
 If you use https://micrometer.io/docs/tracing[Micrometer Tracing], this will be auto-configured for you, but you can always create your own if you want.
 Please check the https://prometheus.io/docs/prometheus/latest/feature_flags/#exemplars-storage[Prometheus Docs], since this feature needs to be explicitly enabled on Prometheus' side, and it is only supported using the https://github.com/OpenObservability/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#exemplars[OpenMetrics] format.
 
 For ephemeral or batch jobs that may not exist long enough to be scraped, you can use https://github.com/prometheus/pushgateway[Prometheus Pushgateway] support to expose the metrics to Prometheus.
+The Prometheus Pushgateway only works with the deprecated Prometheus simpleclient for now, until the Prometheus client 1.x adds support for it.
 To enable Prometheus Pushgateway support, add the following dependency to your project:
 
 [source,xml]