MusicDin/kumuluzee-database-schema-migrations

KumuluzEE Database Schema Migrations

KumuluzEE Database Schema Migrations project for database schema migrations with Liquibase.

KumuluzEE Database Schema Migrations is a database schema migration project for the KumuluzEE microservice framework that provides an easy way to migrate database schemas with Liquibase. It supports migrations at application startup or at runtime when the application is already running.

Usage

You can enable KumuluzEE database schema migrations with Liquibase by adding the following dependency:

<dependency>
    <groupId>com.kumuluz.ee.database-schema-migrations</groupId>
    <artifactId>kumuluzee-database-schema-migrations-liquibase</artifactId>
    <version>${kumuluzee-database-schema-migrations.version}</version>
</dependency>

At least one data source must be configured for the extension to work. For example, PostgreSQL can be used by adding the following dependency:

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>${postgresql.version}</version>
</dependency>

Configure migrations

Liquibase database schema migrations are configured using the common KumuluzEE configuration framework. The configuration properties can be defined via the environment variables or via the configuration file. For more details, see the KumuluzEE configuration wiki page and KumuluzEE Config.

To use Liquibase database schema migrations, at least one data source must be configured.

The only required Liquibase configuration property is jndi-name, which must correspond to a JNDI name of the preconfigured data source.

Minimum configuration for Liquibase database schema migration (without data source configuration):

kumuluzee:
  database-schema-migrations:
    liquibase:
      changelogs:
        - jndi-name: jdbc/example-db             # Required

To specify the location of a custom changelog file, the file property can be used (default is db/changelog-master.xml). The location must be specified relative to the resource directory.

Example configuration:

kumuluzee:
  database-schema-migrations:
    liquibase:
      changelogs:
        - jndi-name: jdbc/example-db
          file: db/changelog-master.xml          # default: "db/changelog-master.xml"

Configure migrations at startup

There are two actions that can be performed when the application starts. One is dropAll and the other is update. The dropAll action drops the database and the update action updates the database according to the changelog at the location specified in the file property. Note that the dropAll action is executed before the update action if both are enabled.

Example configuration:

kumuluzee:
  database-schema-migrations:
    liquibase:
      changelogs:
        - jndi-name: jdbc/example-db
          startup:
            drop-all: false                      # default: false  
            update: true                         # default: false

Disable migrations

To disable database schema migrations at application startup, set kumuluzee.database-schema-migrations.enabled to false (default is true).

kumuluzee:
  database-schema-migrations:
    enabled: false                               # default: true

Contexts and labels

With contexts and labels, Liquibase provides a way to selectively execute changeSets. Contexts allow you to select specific changeSets for execution, while labels allow you to select changeSets for execution using complex expressions (note that the comma (,) in labels means the same as the or operator).

Both contexts and labels can be configured in the KumuluzEE configuration file.

Example configuration:

kumuluzee:
  database-schema-migrations:
    liquibase:
      changelogs:
        - jndi-name: jdbc/example-db
          labels: "label1 and !label2, label3"   # default: ""
          contexts: "context1, context2"         # default: ""

Note that contexts that are not specified are ignored by Liquibase. The same is true for labels.

Database Schema Migrations via CDI

KumuluzEE database schema migrations provide LiquibaseContainer, a wrapper for the Liquibase object, that can be injected via CDI. The Liquibase object provides a way to perform schema migrations on the connected data source at runtime.

The LiquibaseContainer is created by first selecting an appropriate configuration based on the JNDI name specified in the @LiquibaseChangelog annotation, and then connecting it to the appropriate data source. The annotation can also be omitted if only one Liquibase migration is specified in the KumuluzEE configuration file.

Example:

/*
 * Injects LiquibaseContainer if only 1 Liquibase 
 * configuration is specified in the config file.
 */
@Inject
private LiquibaseContainer liquibaseContainer;

/* 
 * Injects LiquibaseContainer if only 1 Liquibase 
 * configuration is specified in the config file.
 */
@Inject
@LiquibaseChangelog
private LiquibaseContainer liquibaseContainer2;

/* 
 * Injects LiquibaseContainer for changelog with the JNDI
 * name specified in the argument of the annotation.
 */
@Inject
@LiquibaseChangelog(jndiName = "jdbc/example-db")
private LiquibaseContainer liquibaseContainer3;

public void dropAll() throws LiquibaseException {

    Liquibase liquibase = liquibaseContainer.createLiquibase();

    liquibase.dropAll();
    liquibase.validate();

}