Introduction to Liquibase

JAXJUG presentation on Liquibase

Transcript

1. Introduction to Liquibase Gary Hale
2. Agenda ⬜ Overview ⬜ Liquibase XML basics ⬜ Liquibase Integrations ⬜ Liquibase + Gradle ⬜ Liquibase Functionality ⬜ Demo
3. Overview ⬜ Liquibase premise: All database changes are stored in a human readable yet trackable form and checked into source control. ⬜ Liquibase allows you to: ⬜ Apply database changes systematically ⬜ Manage changes across environments/platforms ⬜ Rollback changes ⬜ Compare databases ⬜ Generate change documentation
4. Overview ⬜ Incremental changes to code are (in general) simple and atomic – remove the previous version, install the new version ⬜ Database deployments are more tricky: ⬜ Can’t remove the schema and recreate it without wiping out data ⬜ Involves getting the database state from point in time A to point in time B ⬜ Order is important ⬜ Easy for environments to drift apart ⬜ Need to be able to determine the state of the database at any point in time
5. Overview Test Prod Add table Column Width = 4 Column Width = 8 Run dml Add table Column Width = 4 Column Width = 8 Run dml
6. Overview ⬜ Liquibase uses a “changelog” which captures all database changes ⬜ The changelog can be stored in source control (and versioned) to bind a certain database version to a version of code ⬜ Changelogs are composed of “changesets” which are atomic groups of operations that applied and rolled back in increments
7. Overview ⬜ Liquibase supports: ⬜ Multiple databases (e.g. dev, test, prod) ⬜ Multiple database platforms ⬜ Multiple contexts ⬜ DDL, DML, and DCL ⬜ Abstract DSL or plain SQL ⬜ Stored Procedures ⬜ Database Tags
8. XML Basics ⬜ Liquibase can be called from: ⬜ Command Line ⬜ Ant ⬜ Maven ⬜ Spring ⬜ Grails ⬜ Servlet Listener ⬜ Gradle
9. XML Basics ⬜ Sample Change Log: <?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" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-2.0.xsd http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd"> <preConditions> <dbms type="mysql"/> </preConditions> <changeSet id="123-1" author="ghale"> <createTable tableName="person"> <column name="id" type="int" autoIncrement="true"> <constraints primaryKey="true" nullable="false"/> </column> <column name="firstname" type="varchar(50)"/> <column name="lastname" type="varchar(50)"> <constraints nullable="false"/> </column> </createTable> </changeSet> <include file=“/some/other/changelog.xml” /> </databaseChangeLog>
10. XML Basics ⬜ Sample Change Log: <?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" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-2.0.xsd http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd"> <preConditions> <dbms type="mysql"/> </preConditions> <changeSet id="123-1" author="ghale"> <sql> CREATE TABLE `person` (`id` INT AUTO_INCREMENT NOT NULL, `firstname` VARCHAR(50), `lastname` VARCHAR(50) NOT NULL, CONSTRAINT `PK_PERSON` PRIMARY KEY (`id`)) </sql> </changeSet> <include file=“/some/other/changelog.xml” /> </databaseChangeLog>
11. Command Line ⬜ Sample Command Line Invocation: liquibase \ --url=jdbc:mysql://jxlprdbld02:3306/liquibase_demo?auto_reconnect=true \ --classpath=${HOME}/workspaces/developer_config/lib/mysql/mysql-connector-java/5.1.6 /mysql-connector-java-5.1.6.jar \ --changeLogFile=changelog.xml \ --username=liquibase \ --password=lqdem0 \ update
12. Ant Plugin <target name="update-database" depends="prepare"> <fail unless="db.changelog.file">db.changelog.file not set</fail> <fail unless="database.url">database.url not set</fail> <fail unless="database.username">database.username not set</fail> <fail unless="database.password">database.password not set</fail> <taskdef resource="liquibasetasks.properties"> <classpath refid="classpath"/> </taskdef> <updateDatabase changeLogFile="${db.changelog.file}" driver="${database.driver}" url="${database.url}" username="${database.username}" password="${database.password}" promptOnNonLocalDatabase="${prompt.user.if.not.local.database}" dropFirst="false" classpathref="classpath" /> </target>
13. Servlet Listener <context-param> <param-name>liquibase.changelog</param-name> <param-value>com/example/db.changelog.xml</param-value> </context-param> <context-param> <param-name>liquibase.datasource</param-name> <param-value>java:comp/env/jdbc/default</param-value> </context-param> <context-param> <param-name>liquibase.host.includes</param-name> <param-value>production1.example.com, production2.example.com</param-value> </context-param> <context-param> <param-name>liquibase.onerror.fail</param-name> <param-value>true</param-value> </context-param> <context-param> <param-name>liquibase.contexts</param-name> <param-value>production</param-value> </context-param> <listener> <listener-class>liquibase.integration.servlet.LiquibaseServletListener</listener-class> </listener>
14. Spring <bean id="liquibase" class="liquibase.integration.spring.SpringLiquibase"> <property name="dataSource" ref="myDataSource" /> <property name="changeLog" value="classpath:db-changelog.xml" /> </bean>
15. Gradle Plugin ⬜ Allows Liquibase XML to be written as Groovy DSL ⬜ Allows a single build file with multiple database definitions as well as multiple changelog definitions ⬜ Allows mixing of Groovy and XML changelogs if desired
16. Liquibase Functionality ⬜ Status – Prints the current status of the target database and what changesets (if any) need to be applied ⬜ Validate – Validates the changelog checking for errors, etc ⬜ Update – Migrates the database to the current state of the changelog ⬜ UpdateSQL – Prints out the SQL that needs to be executed to migrate the database to the current state of the changelog
17. Liquibase Functionality ⬜ Tag – Tags the current state of the database as a milestone for rollback ⬜ Rollback – Rolls back a database to a specified tag ⬜ RollbackCount – Rolls back a database by specified number of changesets ⬜ RollbackToDate – Rolls back a database to its state on a specified date
18. Liquibase Functionality ⬜ RollbackSQL – Prints the SQL that needs to be executed to rollback to the specified tag ⬜ UpdateTestingRollback – For each changeset, migrates the database to include the changeset, rolls it back and migrates again (tests rollback as part of the database migration) ⬜ GenerateChangeLog – Generates a change log from an existing database (does not include stored procedures)
19. Liquibase Functionality ⬜ Diff – Diffs two databases to determine what’s different based on the changelog. ⬜ Database contexts allow you to specify certain changesets which should only be applied when a given context is in effect.
20. Demo
21. Questions ?