Unlocking the Power of Liquibase: A Step-by-Step Guide to Generating Changelogs with Quarkus and the Liquibase Hibernate Extension

Are you tired of manually creating and managing database changelogs? Look no further! In this comprehensive guide, we’ll show you how to generate Liquibase changelogs with Quarkus using the Liquibase Hibernate extension. By the end of this article, you’ll be equipped with the knowledge to automate database migrations and streamline your development workflow.

What is Liquibase?

Liquibase is an open-source database change management tool that provides a flexible and efficient way to manage database schema changes. It enables you to track, version, and deploy database changes across different environments, ensuring that your database is always in sync with your application code.

What is Quarkus?

Quarkus is a Kubernetes-native Java framework that enables you to build lightweight, fast, and efficient applications. It provides a set of libraries and tools that make it easy to develop cloud-native applications. Quarkus is an excellent choice for building modern web applications, and when combined with Liquibase, it provides a robust solution for managing database schema changes.

What is the Liquibase Hibernate Extension?

The Liquibase Hibernate extension is a plugin that integrates Liquibase with Hibernate, a popular Java-based ORM (Object-Relational Mapping) tool. This extension enables you to generate Liquibase changelogs from your Hibernate entities, making it easy to manage database schema changes as part of your application development lifecycle.

Prerequisites

Before we dive into the tutorial, make sure you have the following prerequisites installed:

• Java 11 or later
• Maven 3.6.0 or later
• Quarkus 2.5.0 or later
• Liquibase 4.3.2 or later
• Hibernate 5.4.20 or later

Step 1: Create a Quarkus Project

First, create a new Quarkus project using the following command:

mvn io.quarkus:quarkus-maven-plugin:2.5.0.Final:create \
    -DprojectGroupId=com.example \
    -DprojectArtifactId=quarkus-liquibase-example \
    -DprojectVersion=1.0.0 \
    -DclassName="com.example.quarkus.liquibase.example.QuarkusLiquibaseExample"

This will create a new Quarkus project with the specified group ID, artifact ID, and version.

Step 2: Add Dependencies

In the `pom.xml` file, add the following dependencies:

<dependencies>
    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-hibernate-orm</artifactId>
    </dependency>
    <dependency>
        <groupId>org.liquibase</groupId>
        <artifactId>liquibase-core</artifactId>
    </dependency>
    <dependency>
        <groupId>org.liquibase</groupId>
        <artifactId>liquibase-hibernate</artifactId>
    </dependency>
</dependencies>

These dependencies will enable us to use Hibernate ORM, Liquibase core, and the Liquibase Hibernate extension.

Step 3: Configure Liquibase

In the `application.properties` file, add the following configuration:

liquibase.change-log=classpath:/db/changelog/db.changelog-master.xml
liquibase.url=jdbc:postgresql://localhost:5432/mydb
liquibase.username=myuser
liquibase.password=mypassword
liquibase.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect

This configuration tells Liquibase to use the `db.changelog-master.xml` file as the changelog, connects to a PostgreSQL database, and uses the Hibernate dialect for PostgreSQL.

Step 4: Create a Hibernate Entity

Create a new Java class `User.java` in the `com.example.quarkus.liquibase.example` package:

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;
    
    // getters and setters
}

This simple entity represents a user with an ID, name, and email.

Step 5: Generate the Liquibase Changelog

The magic happens here! Create a new Java class `LiquibaseGenerator.java` in the `com.example.quarkus.liquibase.example` package:

@QuarkusApplication
public class LiquibaseGenerator {
    
    @Inject
    HibernateEntityManagerFactory entityManagerFactory;
    
    public static void main(String[] args) {
        Quarkus.run(LiquibaseGenerator.class);
    }
    
    @QuarkusLifecycle
    public void generateLiquibaseChangelog() {
        Connection connection = entityManagerFactory.getConnectionProvider().getConnection();
        Database database = DatabaseFactory.getInstance().findCorrectDatabaseImplementation(new OfflineConnection(connection));
        Liquibase liquibase = new Liquibase("db/changelog", new FileSystemResourceAccessor(), database);
        liquibase.setChangeLogFile("db/changelog/db.changelog-master.xml");
        liquibase.update(new Contexts());
    }
}

This class uses the Quarkus Hibernate extension to create a Hibernate entity manager factory, connects to the database, and generates the Liquibase changelog using the Hibernate entities.

Step 6: Run the Application

Run the Quarkus application using the following command:

mvn quarkus:dev

This will start the Quarkus application, and the `LiquibaseGenerator` class will generate the Liquibase changelog based on the Hibernate entities.

The Generated Changelog

After running the application, you’ll find the generated `db.changelog-master.xml` file in the `src/main/resources` directory:

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
    xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                      http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">

    <changeSet id="1" author="quarkus-liquibase-example">
        <createTable tableName="USER">
            <column name="ID" type="BIGINT">
                <constraints primaryKey="true" nullable="false"/>
            </column>
            <column name="NAME" type="VARCHAR(255)"/>
            <column name="EMAIL" type="VARCHAR(255)"/>
        </createTable>
    </changeSet>

</databaseChangeLog>

This changelog contains a single changeset that creates a `USER` table with columns for `ID`, `NAME`, and `EMAIL`.

Conclusion

In this article, we’ve demonstrated how to generate Liquibase changelogs with Quarkus using the Liquibase Hibernate extension. By following these steps, you can automate database schema changes and streamline your development workflow. Remember to adapt this guide to your specific use case and requirements.

Technologies	Versions
Java	11 or later
Maven	3.6.0 or later
Quarkus	2.5.0 or later
Liquibase	4.3.2 or later
Hibernate	5.4.20 or later

We hope you found this guide helpful! If you have any questions or feedback, feel free to leave a comment below.

Further Reading

• Liquibase Documentation
• Quarkus Documentation
• Hibernate Documentation

Happy coding!

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