poc-quarkus-multiple-datasources project

This is a simple poc using multiple data sources with Quarkus.

Quoting the Quarkus documentation:

Starting with Quarkus 1.8, you can define multiple persistence units using the Quarkus configuration properties approach.

Two datasources are defined in src/resources/application.properties:

• Users:
  • PostgreSQL
• Orders:
  • MariaDB or Oracle.
  • Oracle is initially commented, because the Oracle JDBC driver must be downloaded manually. There are instructions below to change beteween MariaDB and Oracle.

The main project is on the Quarkus 1.9.2.Final version.

There are other three projects available here in more recent versions

• Quarkus version 2.7.4.Final using only Hibernate - folder ./quarkus-vrs-2-7-hibernate
• Quarkus version 2.7.4.Final using only Panache with the Repository Pattern - folder ./quarkus-vrs-2-7-panache-repository-pattern
• Quarkus version 2.7.4.Final using only Panache with the Active Record Pattern - folder ./quarkus-vrs-2-7-panache-active-record-pattern

Steps to run the test with PostgreSQL and Mariadb

1. Start the database docker images;

docker run -d --name postgres-db -p 5432:5432 -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=postgres -e POSTGRES_DB=usersdb postgres
docker run -d --name mariadb-db -p 3306:3306 -e MYSQL_USER=maria -e MYSQL_ROOT_PASSWORD=maria -e MYSQL_PASSWORD=maria -e MYSQL_DATABASE=ordersdb mariadb

2. Start Quarkus at dev mode:

./mvnw compile quarkus:dev

3. Or you can run inside docker-compose:

chmod +x ./run.sh
./run.sh

4. From a browser access http://localhost:8080/swagger-ui and the test:
   • /users/list - select data from the PostgreSQL;
   • /orders/list - select data from the MariaDB (or Oracle database);

Change MariaDB to Oracle:

To test with the Oracle database, you need to:

1. Download the Oracle JDBC driver
2. Put this driver at your Maven repository at: /com/oracle/jdbc/ojdbc8/12.2.0.1
3. Uncomment the Oracle JDBC dependency at the pom.xml:

    <dependency>
      <groupId>com.oracle.jdbc</groupId>
      <artifactId>ojdbc8</artifactId>
      <version>12.2.0.1</version>
    </dependency>

4. In the src/resources/application.properties, comment the MariaDB parameters and uncomment the Oracle parameters;
5. Start the docker container:

docker run -d --name oracle-db -p 1521:1521 -e ORACLE_DISABLE_ASYNCH_IO=true oracleinanutshell/oracle-xe-11g

6. Run the application and be happy!

In case you want to see the data from a client, as DBeaver, use the following parameters:

• Type: SID
• User: system
• Password: oracle

Test Oracle Docker image origin:./mvnw compile quarkus:dev

Quarkus documentation:

• https://quarkus.io/guides/datasource#multiple-datasources
• https://quarkus.io/guides/hibernate-orm#multiple-persistence-units

Tip to pass environment variable to property with double quotes

To override a property like host."foo".bar with an environment variable it's necessary to put two underlines (__).

host."foo".bar it will be overriden with: export HOST__FOO__BAR=your_host

In this projet:

• quarkus.datasource."users".jdbc.url
• export QUARKUS_DATA_SOURCE__USERS__JDBC_URL=your_url

Quarkus

This project uses Quarkus, the Supersonic Subatomic Java Framework.

If you want to learn more about Quarkus, please visit its website: https://quarkus.io/ .

Running the application in dev mode

You can run your application in dev mode that enables live coding using:

./mvnw compile quarkus:dev

Packaging and running the application

The application can be packaged using:

./mvnw package

It produces the poc-quarkus-multiple-datasources-1.0.0-SNAPSHOT-runner.jar file in the /target directory. Be aware that it’s not an über-jar as the dependencies are copied into the target/lib directory.

If you want to build an über-jar, execute the following command:

./mvnw package -Dquarkus.package.type=uber-jar

The application is now runnable using java -jar target/poc-quarkus-multiple-datasources-1.0.0-SNAPSHOT-runner.jar.

Creating a native executable

You can create a native executable using:

./mvnw package -Pnative

Or, if you don't have GraalVM installed, you can run the native executable build in a container using:

./mvnw package -Pnative -Dquarkus.native.container-build=true

You can then execute your native executable with: ./target/poc-quarkus-multiple-datasources-1.0.0-SNAPSHOT-runner

If you want to learn more about building native executables, please consult https://quarkus.io/guides/maven-tooling.html.