Helidon¶

Helidon MP¶

Command line¶

Migrax reads META-INF/microprofile-config.properties (and the mp.config.profile) together with META-INF/persistence.xml:

META-INF/microprofile-config.properties

javax.sql.DataSource.shop.dataSourceClassName=org.postgresql.ds.PGSimpleDataSource
javax.sql.DataSource.shop.dataSource.url=jdbc:postgresql://localhost:5432/shop
javax.sql.DataSource.shop.dataSource.user=shop
javax.sql.DataSource.shop.dataSource.password=secret

META-INF/persistence.xml

<persistence-unit name="shop" transaction-type="JTA">
  <jta-data-source>shop</jta-data-source>
  <properties>
    <property name="hibernate.hbm2ddl.auto" value="none"/>
  </properties>
</persistence-unit>

When several data sources are configured, Migrax uses the one persistence.xml names. The jdbcUrl, username and password keys of other connection pools work too, and so do the MicroProfile environment variables, such as JAVAX_SQL_DATASOURCE_SHOP_DATASOURCE_URL. hibernate.* properties from persistence.xml are passed to Hibernate.

Naming: Helidon keeps Hibernate's default naming (jpa).

Migrate at startup¶

<dependency>
  <groupId>org.migrax</groupId>
  <artifactId>migrax-helidon</artifactId>
  <version>0.4.0</version>
</dependency>

Migrations run when the application starts, before your own beans and before JPA is first used, so hibernate.hbm2ddl.auto=validate works. Settings go in microprofile-config.properties:

Setting	Default	Meaning
`migrax.enabled`	`true`	Apply migrations at startup
`migrax.datasource`	the one `persistence.xml` names, or the only one	Data source to migrate
`migrax.locations`	`db/migration`	Migration folder on the classpath
`migrax.java-package`	`db.migration`	Package of `JavaMigration` classes
`migrax.resume`	`false`	Re-run a failed migration marked `-- migrax:resume-safe`
`migrax.lock-timeout`	`0`	How long to wait while another instance migrates, for example `2m` when several start together
`migrax.placeholders.<name>`		Values for `${name}` placeholders
`migrax.schemas`		Schemas to migrate one after another

Readiness check¶

With helidon-microprofile-health in the application, Migrax adds a migrax readiness check: UP when every migration is applied and none failed, was edited or is missing, DOWN otherwise, with the counts as data (/health/ready).

Helidon SE¶

Helidon SE uses its database client rather than JPA, so there are no entities to generate migrations from. Write migrations with migrax new and apply them with migrax migrate in your deployment. Migrax reads the connection from application.yaml:

db:
  connection:
    url: jdbc:postgresql://localhost:5432/shop
    username: shop
    password: secret