Using Liquibase with Cassandra on DataStax Astra

The purpose of this document is to guide you through the process of creating a new Liquibase project with Cassandra. In this tutorial, you will generate an example project and follow the instructions to apply and learn concepts associated with creating new Liquibase projects with Cassandra on DataStax Astra.

Prerequisites

• If you have not installed the latest version of Liquibase, navigate to https://www.liquibase.org/download to install Liquibase latest release.
• Ensure the Liquibase install directory path is set to a location in the PATH System variable.
• Navigate to https://downloads.datastax.com/#odbc-jdbc-drivers and download the Simba jdbc jar driver file for Apache Cassandra.
• Navigate to https://github.com/liquibase/liquibase-cassandra/releases/ and download the liquibase-cassandra-<version>.jar latest release extension jar file.
• Place the two jar files in the liquibase/lib install directory.
• Log into your DataStax Astra account from the following URL https://astra.datastax.com/. From Dashboard click connect on the desired Database > Under "Connect using an API, choose "Java" > download the Connect Bundle by clicking the link in step 1 under Prerequisites.
• Once the secure-connect-<dbname>.zip is fully downloaded, place it somewhere in a secure place in your file system.
• Unzip the secure-connect-<dbname>.zip file. Open the config.json file in a text editor and leave it open. We will use that information in this file later to configure our Liquibase project.
• Clone this repository to set up CQL-Proxy which is a sidecar that enables unsupported CQL drivers to work with DataStax Astra.
• You need your Astra Token and Astra Database ID to use CQL-Proxy
• Follow the steps in the repo to spin up CQL-Proxy using Terminal/Command Line. Once successfully running, you should see the following output:
{"level":"info","ts":1651012815.176512,"caller":"proxy/proxy.go:222","msg":"proxy is listening","address":"[::]:9042"}

Tutorial

To create a Liquibase project with Cassandra on DataStax Astra on your machine, begin with the following steps:

1. Create a new project folder and name it LiquibaseProj.
2. In your LiquibaseProj folder, create a new text file and name it dbchangelog.sql.
3. Open the dbchangelog.sql file and update the changelog file with the following code snippet:

--liquibase formatted sql

4. In your LiquibaseProj folder, create a new text file and name it liquibase.properties.
5. Add the following properties to the newly created Liquibase properties file:

changelog-file: dbchangelog.sql
                changelog-file: dbchangelog.sql
                url: jdbc:cassandra://localhost:9042/test;DefaultKeyspace=test;TunableConsistency=6
                driver: com.simba.cassandra.jdbc42.Driver
                defaultSchemaName: test
                liquibase.hub.mode=off                

In the Liquibase liquibase.properties file, replace test with your own keyspace name

Tip: To apply a Liquibase Pro key to your project, add the following property to the Liquibase properties file: liquibaseProLicenseKey: <paste code here>

6. Add a changeset to the changelog – changeset are uniquely identified by author and id attributes. Liquibase attempts to execute each changeset in a transaction that is committed at the end. In the dbchangelog.sql file, add a new changeset with a create table statement. We will create a new table department using a changeset as follows:

--liquibase formatted sql

--changeset bob:1
CREATE TABLE keyspace.DEPARTMENT (id int, NAME text, ACTIVE BOOLEAN);

7. Open the command prompt. Navigate to the LiquibaseProj directory.
   Run the following command: liquibase update
8. From a SQL Client User Interface, check your database changes. You should see a new department table added to the database. For example:

SELECT * FROM "keyspace"."department";

ID	NAME	ACTIVE
NULL	NULL	NULL

From a database UI tool, ensure that your database contains the table you added along with the DATABASECHANGELOG table and DATABASECHANGELOGLOCK table.