Using Liquibase with Cloud Spanner

Cloud Spanner is a fully managed relational database with unlimited scale and strong consistency. It optimizes performance by automatically sharding the data based on request load and size of the data.

You can use the Cloud Spanner Liquibase Extension to manage database schema changes with Liquibase. With the Cloud Spanner Liquibase extension, you can enable Liquibase to target Cloud Spanner. All Cloud Spanner features, with the exception of some limitations, are supported.

Additionally, the example changelog.yaml included with the Cloud Spanner Liquibase extension demonstrates Liquibase features and how to use them with Cloud Spanner.

Supported database versions

  • 2.7.3

Prerequisites

  1. Introduction to Liquibase – Dive into Liquibase concepts.
  2. Install Liquibase – Download Liquibase on your machine.
  3. Get Started with Liquibase – Learn how to use Liquibase with an example database.
  4. Design Your Liquibase Project – Create a new Liquibase project folder and organize your changelogs
  5. How to Apply Your Liquibase Pro License Key – If you use Liquibase Pro, activate your license.

Install drivers

To use Liquibase and Cloud Spanner, you need the Cloud Spanner Liquibase extension file, liquibase-spanner-version-all.jar, which includes the extension, the Cloud Spanner SDK, and the Cloud Spanner JDBC driver. You can also download the JDBC driver from the Central Maven Repository.

Place your JAR file(s) in the liquibase/lib directory.

If you use Maven, you must include the driver JAR as a dependency in your pom.xml file.

<dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-spanner-jdbc</artifactId>
    <version>2.7.3</version>
</dependency>
<dependency>
    <groupId>org.liquibase.ext</groupId>
    <artifactId>liquibase-cassandra</artifactId>
    <version>4.10.0</version>
</dependency>

Test your connection

  1. Ensure you have created the Cloud Spanner instance and database. Then give the extension temporary use of your own Cloud Spanner user credentials for API access by running the following gcloud command:
  2. gcloud auth application-default login
  3. Specify the database URL in the liquibase.properties file (defaults file), along with other properties you want to set a default value for. Liquibase does not parse the URL. You can either specify the full database connection string or specify the URL using your database's standard JDBC format:
  4. url: jdbc:cloudspanner:/projects/<project>/instances/<instance>/databases/<database>

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

  1. Create a text file called changelog (.xml, .sql, .json, or .yaml) in your project directory and add a changeset.
  2. If you already created a changelog using the init project command, you can use that instead of creating a new file. When adding onto an existing changelog, be sure to only add the changeset and to not duplicate the changelog header.

    XML example
    <?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"
        xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
        xmlns:pro="http://www.liquibase.org/xml/ns/pro"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
            http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
            http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd
            http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd">
    
        <changeSet id="1" author="Liquibase">
            <createTable tableName="test_table">
                <column name="test_id" type="int">
                    <constraints primaryKey="true"/>
                </column>
                <column name="test_column" type="varchar"/>
            </createTable>
        </changeSet>
    
    </databaseChangeLog>
    SQL example
    -- liquibase formatted sql
    
    -- changeset liquibase:1
    CREATE TABLE test_table (test_id INT, test_column VARCHAR(255), PRIMARY KEY (test_id))

    Tip: Formatted SQL changelogs generated from Liquibase versions before 4.2 might cause issues because of the lack of space after a double dash ( -- ). To fix this, add a space after the double dash. For example: -- liquibase formatted sql instead of --liquibase formatted sql and -- changeset myname:create-table instead of --changeset myname:create-table.

    YAML example
    databaseChangeLog:
       - changeSet:
           id: 1
           author: Liquibase
           changes:
           - createTable:
               tableName: test_table
               columns:
               - column:
                   name: test_column
                   type: INT
                   constraints:
                       primaryKey:  true
                       nullable:  false
    JSON example
    {
      "databaseChangeLog": [
        {
          "changeSet": {
            "id": "1",
            "author": "Liquibase",
            "changes": [
              {
                "createTable": {
                  "tableName": "test_table",
                  "columns": [
                    {
                      "column": {
                        "name": "test_column",
                        "type": "INT",
                        "constraints": {
                          "primaryKey": true,
                          "nullable": false
                        }
                      }
                    }
                  ]
                }
              }
            ]
          }
        }
      ]
    }
  3. Navigate to your project folder in the CLI and run the Liquibase status command to see whether the connection is successful:
  4. liquibase status --username=test --password=test --changelog-file=<changelog.xml>

    Note: You can specify arguments in the CLI or keep them in the Liquibase properties file.

    If your connection is successful, you'll see a message like this:

    4 changesets have not been applied to <your_jdbc_url>
    Liquibase command 'status' was executed successfully.
  5. Inspect the SQL with the update-sql command. Then make changes to your database with the update command.
  6. liquibase update-sql --changelog-file=<changelog.xml>
    liquibase update --changelog-file=<changelog.xml>

    If your update is successful, Liquibase runs each changeset and displays a summary message ending with:

    Liquibase: Update has been successful.
    Liquibase command 'update' was executed successfully.
  7. From a database UI tool, ensure that your database contains the test_table you added along with the DATABASECHANGELOG table and DATABASECHANGELOGLOCK table.

Now you're ready to start making deployments with Liquibase!

You can verify the existence of these tables through the Cloud Console or gcloud tool. For example, running the SQL query SELECT * FROM INFORMATION_SCHEMA.TABLES returns a list of all tables in your database:

gcloud spanner databases execute-sql <DB>  --instance=<INSTANCE> \
--sql='SELECT * FROM INFORMATION_SCHEMA.TABLES'

Related links