Add JPA statistics support for eclipselink and hibernate (#2202)

Signed-off-by: Avgustin Marinov <Avgustin.Marinov@bosch.com>

hawkbit-repository/hawkbit-repository-jpa-hibernate/pom.xml

@@ -36,6 +36,12 @@
             <artifactId>hibernate-core</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-core</artifactId>
+            <optional>true</optional>
+        </dependency>
+
         <!-- Static class generation -->
         <dependency>
             <groupId>org.hibernate.orm</groupId>

hawkbit-repository/hawkbit-repository-jpa-hibernate/src/main/java/org/eclipse/hawkbit/repository/jpa/Statistics.java

@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) 2025 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.hawkbit.repository.jpa;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import lombok.Getter;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * (Experimental) Report Hibernate statistics to Micrometer.
+ * <p/>
+ * To be enabled:
+ * <ol>
+ *     <li>The Spring property spring.jpa.properties.hibernate.generate_statistics=true shall be set - enables Hibernate statistics
+ *         collecting</li>
+ *     <li>If don't need log in the stdout set logging.level.org.hibernate.engine.internal.StatisticalLoggingSessionEventListener=WARN</li>
+ *     <li>The MeterRegistry shall be registered available - e.g. include org.springframework.boot:spring-boot-actuator-autoconfigure</li>
+ *     <li>Hibernate reporting to micrometer shall be enabled - include org.hibernate.orm:hibernate-micrometer</li>
+ *     <li>(?) When using in test the metrics MAYBE shall be enabled with @AutoConfigureObservability(tracing = false)</li>
+ * </ol>
+ */
+public class Statistics {
+
+    public static final String METER_PREFIX = "hibernate.";
+
+    private static final Statistics INSTANCE = new Statistics();
+
+    // if meter registry is unavailable, the statistics will not send to metrics
+    @Getter
+    public MeterRegistry meterRegistry;
+
+    /**
+     * @return the singleton {@link Statistics} instance
+     */
+    public static Statistics getInstance() {
+        return INSTANCE;
+    }
+
+    @Autowired
+    public void setMeterRegistry(final MeterRegistry meterRegistry) {
+        this.meterRegistry = meterRegistry;
+    }
+
+    // flushes the statistics to the meter registry (if needed)
+    public static void flush() {
+        // nothing to do for Hibernate
+    }
+
+    // autoconfigure after CompositeMeterRegistryAutoConfiguration, so when the autoconfiguration is being processed the MeterRegistry
+    // has already been registered / resolved (if it is to be registered at all) - otherwise @ConditionalOnBean(MeterRegistry.class) may not be
+    // met event if the MeterRegistry is registered (if resolved later).
+    // 'autoconfigure after' relies on this is being an AutoConfiguration
+    @AutoConfiguration(afterName = "org.springframework.boot.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration")
+    @Configuration
+    public static class StatisticsAutoConfiguration {
+
+        @ConditionalOnProperty(prefix = "spring.jpa.properties.hibernate", name = "generate_statistics", havingValue = "true")
+        @ConditionalOnBean(MeterRegistry.class)
+        @Bean
+        public Statistics statistics() {
+            // injects the singleton Statistics, and start scheduler
+            return Statistics.getInstance();
+        }
+    }
+}

hawkbit-repository/hawkbit-repository-jpa-hibernate/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -0,0 +1 @@
+org.eclipse.hawkbit.repository.jpa.Statistics.StatisticsAutoConfiguration