🗃️ db(postgres): add PostgresEventStorageEngine sample usage

.gitignore

@@ -32,4 +32,10 @@ build/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+
+### Docker ###
+volumes
+
+### App ###
+logs

docker-compose.yaml

@@ -9,8 +9,19 @@ services:
       axoniq_axonserver_autocluster_first: axon-server
       axoniq_axonserver_autocluster_contexts: _admin
     volumes:
-      - data:/axonserver/data
-      - events:/axonserver/events
+      - ./volumes/axonserver-data:/axonserver/data
+      - ./volumes/axonserver-events:/axonserver/events
+  postgres:
+    image: postgres:18
+    environment:
+      POSTGRES_DB: university_demo_db
+      POSTGRES_USER: university_demo_user
+      POSTGRES_PASSWORD: university_demo_password
+    ports:
+      - "5444:5444"
+    volumes:
+      - ./volumes/postgres-axon:/var/lib/postgresql/18/docker
+    command: -p 5444
 
 volumes:
   db:

pom.xml

@@ -21,6 +21,9 @@
         <java.version>21</java.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven-surefire-plugin.version>3.2.5</maven-surefire-plugin.version>
+        <axon-postgresql.version>0.1.0</axon-postgresql.version>
+        <postgresql.version>42.7.8</postgresql.version>
+        <hikari-cp.version>7.0.2</hikari-cp.version>
     </properties>
 
     <dependencies>
@@ -61,6 +64,22 @@
             <version>${axon.version}</version>
         </dependency>
 
+        <dependency>
+            <groupId>io.axoniq.framework</groupId>
+            <artifactId>postgresql-core</artifactId>
+            <version>${axon-postgresql.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>${postgresql.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>HikariCP</artifactId>
+            <version>${hikari-cp.version}</version>
+        </dependency>
+
         <!-- Serialization Dependencies -->
 
         <dependency>

src/main/java/io/axoniq/demo/university/ConfigurationProperties.java

@@ -9,7 +9,8 @@
 public class ConfigurationProperties {
     private static final Logger logger = Logger.getLogger(ConfigurationProperties.class.getName());
 
-    boolean axonServerEnabled = true;
+    // Possible values: "in-memory", "axonserver", "postgres"
+    private String eventStorageEngine = "axonserver";
 
     public static ConfigurationProperties defaults() {
         return new ConfigurationProperties();
@@ -21,9 +22,9 @@ public static ConfigurationProperties load() {
         Properties properties = loadPropertiesFile("application.properties");
 
         if (properties != null) {
-            String axonServerEnabled = properties.getProperty("axon.server.enabled");
-            if (axonServerEnabled != null) {
-                props.axonServerEnabled = Boolean.parseBoolean(axonServerEnabled);
+            String engine = properties.getProperty("axon.event-storage.engine");
+            if (engine != null && !engine.isBlank()) {
+                props.eventStorageEngine = engine.trim();
             }
         } else {
             logger.info("No properties file found, using default configuration");
@@ -46,12 +47,20 @@ private static Properties loadPropertiesFile(String filename) {
         return null;
     }
 
-    public boolean axonServerEnabled() {
-        return axonServerEnabled;
+    public String eventStorageEngine() {
+        return eventStorageEngine;
     }
 
-    public ConfigurationProperties axonServerEnabled(boolean axonServerEnabled) {
-        this.axonServerEnabled = axonServerEnabled;
+    public ConfigurationProperties eventStorageEngine(String eventStorageEngine) {
+        this.eventStorageEngine = eventStorageEngine;
         return this;
     }
+
+    public boolean isAxonServerEventStorageEngine() {
+        return "axonserver".equalsIgnoreCase(eventStorageEngine);
+    }
+
+    public boolean isPostgresEventStorageEngine() {
+        return "postgres".equalsIgnoreCase(eventStorageEngine);
+    }
 }

src/main/java/io/axoniq/demo/university/UniversityAxonApplication.java

@@ -1,14 +1,20 @@
 package io.axoniq.demo.university;
 
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
 import io.axoniq.demo.university.faculty.FacultyModuleConfiguration;
 import io.axoniq.demo.university.shared.ids.CourseId;
 import io.axoniq.demo.university.faculty.write.createcourseplain.CreateCourse;
 import io.axoniq.demo.university.faculty.write.renamecourse.RenameCourse;
+import io.axoniq.framework.postgresql.DataSourceConnectionExecutor;
+import io.axoniq.framework.postgresql.PostgresqlEventStorageEngine;
 import org.axonframework.axonserver.connector.AxonServerConfiguration;
 import org.axonframework.axonserver.connector.AxonServerConfigurationEnhancer;
 import org.axonframework.commandhandling.gateway.CommandGateway;
 import org.axonframework.common.infra.FilesystemStyleComponentDescriptor;
 import org.axonframework.configuration.AxonConfiguration;
+import org.axonframework.eventhandling.conversion.DelegatingEventConverter;
+import org.axonframework.eventhandling.conversion.EventConverter;
 import org.axonframework.eventsourcing.configuration.EventSourcingConfigurer;
 
 import java.util.function.UnaryOperator;
@@ -53,7 +59,7 @@ public EventSourcingConfigurer configurer(
             UnaryOperator<EventSourcingConfigurer> customization
     ) {
         var configurer = EventSourcingConfigurer.create();
-        if (configProps.axonServerEnabled) {
+        if (configProps.isAxonServerEventStorageEngine()) {
             configurer.componentRegistry(r -> r.registerComponent(AxonServerConfiguration.class, c -> {
                 var axonServerConfig = new AxonServerConfiguration();
                 axonServerConfig.setContext(CONTEXT);
@@ -62,6 +68,23 @@ public EventSourcingConfigurer configurer(
         } else {
             configurer.componentRegistry(r -> r.disableEnhancer(AxonServerConfigurationEnhancer.class));
         }
+        if (configProps.isPostgresEventStorageEngine()) {
+            HikariConfig config = new HikariConfig();
+
+            config.setJdbcUrl("jdbc:postgresql://localhost:5444/university_demo_db");
+            config.setUsername("university_demo_user");
+            config.setPassword("university_demo_password");
+            config.setAutoCommit(false);
+            config.setMaximumPoolSize(5);
+            config.setMinimumIdle(1);
+
+            configurer.registerEventStorageEngine(cr ->
+                    new PostgresqlEventStorageEngine(
+                            new DataSourceConnectionExecutor(new HikariDataSource(config)),
+                            cr.getComponent(EventConverter.class)
+                    )
+            );
+        }
         configurer = customization.apply(configurer);
         return configurer;
     }

src/main/resources/application.properties

@@ -1,2 +1,4 @@
 # University Demo Application Configuration
-axon.server.enabled=true
+
+#  Options: in-memory / axonserver / postgres
+axon.event-storage.engine=postgres

src/main/resources/log4j2.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="WARN">
+    <Appenders>
+        <Console name="Console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
+        </Console>
+
+        <RollingFile name="RollingFileAppender" fileName="logs/application.log" 
+                     filePattern="logs/application-%i.log.gz">
+            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
+            <Policies>
+                <SizeBasedTriggeringPolicy size="10MB"/>
+            </Policies>
+            <DefaultRolloverStrategy max="5"/>
+        </RollingFile>
+    </Appenders>
+
+    <Loggers>
+        <!-- Axon Framework logging -->
+        <Logger name="org.axonframework" level="DEBUG" additivity="false">
+            <AppenderRef ref="Console"/>
+            <AppenderRef ref="RollingFileAppender"/>
+        </Logger>
+
+        <!-- Application logging -->
+        <Logger name="io.axoniq.demo.university" level="DEBUG" additivity="false">
+            <AppenderRef ref="Console"/>
+            <AppenderRef ref="RollingFileAppender"/>
+        </Logger>
+
+        <!-- Root logger for all other packages -->
+        <Root level="INFO">
+            <AppenderRef ref="Console"/>
+            <AppenderRef ref="RollingFileAppender"/>
+        </Root>
+    </Loggers>
+</Configuration>

src/test/java/io/axoniq/demo/university/UniversityApplicationTest.java

@@ -32,8 +32,8 @@ void beforeEach() {
     }
 
     private static void purgeAxonServerIfEnabled(ConfigurationProperties configuration) {
-        boolean axonServerEnabled = configuration.axonServerEnabled();
-        if (axonServerEnabled) {
+        boolean useAxonServer = configuration.isAxonServerEventStorageEngine();
+        if (useAxonServer) {
             try {
                 AxonServerContainerUtils.purgeEventsFromAxonServer("localhost", 8024, "university", true);
             } catch (IOException e) {

src/test/java/io/axoniq/demo/university/faculty/FacultyAxonTestFixture.java

@@ -20,12 +20,12 @@ public static AxonTestFixture slice(UnaryOperator<EventSourcingConfigurer> custo
         var configuration = ConfigurationProperties.load();
         var configurer = application.configurer(configuration, customization);
         purgeAxonServerIfEnabled(configuration);
-        return AxonTestFixture.with(configurer, c -> configuration.axonServerEnabled() ? c : c.disableAxonServer());
+        return AxonTestFixture.with(configurer, c -> configuration.isAxonServerEventStorageEngine() ? c : c.disableAxonServer());
     }
 
     private static void purgeAxonServerIfEnabled(ConfigurationProperties configuration) {
-        boolean axonServerEnabled = configuration.axonServerEnabled();
-        if (axonServerEnabled) {
+        boolean useAxonServer = configuration.isAxonServerEventStorageEngine();
+        if (useAxonServer) {
             try {
                 AxonServerContainerUtils.purgeEventsFromAxonServer("localhost", 8024, "university", true);
             } catch (IOException e) {

src/test/java/io/axoniq/demo/university/faculty/write/subscribestudent/SubscribeStudentToCourseAxonFixtureTest.java

@@ -36,6 +36,7 @@ void successfulSubscription() {
                 .when()
                 .command(new SubscribeStudentToCourse(studentId, courseId))
                 .then()
+                .success()
                 .events(new StudentSubscribedToCourse(studentId, courseId));
     }
 

src/test/java/io/axoniq/demo/university/faculty/write/subscribestudentmulti/SubscribeStudentToCourseAxonFixtureTest.java

@@ -36,6 +36,7 @@ void successfulSubscription() {
                 .when()
                 .command(new SubscribeStudentToCourse(studentId, courseId))
                 .then()
+                .success()
                 .events(new StudentSubscribedToCourse(studentId, courseId));
     }
 

src/test/resources/application.properties

@@ -1,3 +1,4 @@
-# University Demo Test Configuration
-axon.server.enabled=false
+# University Demo Application Configuration
 
+#  Options: in-memory / axonserver / postgres
+axon.event-storage.engine=postgres