DB migrations (Liquibase + Maven + Spring)

Question

I'm coming from a .Net background cutting my teeth on a Java project that is using Maven, Spring and Liquibase. Needless to say, this is a new bag of concepts and frameworks to deal with.

Tests won't complete:

My tests wont complete successfully because they fail when attempting to access a table within my database. They fail because that table doesn't exist. I see that I have many migration files in a Liquibase XML format within my project, but am looking at how to run them.

liquibase-maven-plugin not an option:

I see that others might use the liquibase-maven-plugin plugin, but in my case, the project does not have that plugin referenced in any the pom.xml, only liquibase-core. There are a handful of other developers that knew what they were doing that worked on this project in the past, given that they never referenced this plugin in the pom.xml file, I assume it was for good reason and I wont be stirring that pot.

SpringLiquibase?

They have a reference to to a bean that looks like this: <bean id="liquibase" class="liquibase.integration.spring.SpringLiquibase">, which after further research appears to do automatic data migrations,

GREAT!

....but how do I go about invoking it? Must my project already pass my Tests and actually be "ran" before this logic gets hit? If that is the case and my project must successfully build / test, then I apparently must run my migrations outside of this SpringLiquibase bean.

Should I be using the liquibase command line and if so, can I safely assume this is what the previous developers were doing to initially establish their database?

Answer 1

You are right that the SpringLiquibase setup should do the database update automatically, but it will only do it when the spring framework is started.

My guess is that your normal application startup fires Liquibase through Spring but the test framework does not. Perhaps they had not noticed it because they would tend to make the database change in the liquibase changelog files, then start the normal application for initial testing (which updated the database) then build and run the tests. Now that you are running the tests first, the database is not yet there.

Are you able to tell if your tests are trying to start Spring?

Even in cases where an application is using SpringLiquibase, I usually recommend configuring your project to allow manual updates using liquibase-maven-plugin, ant plugin, or command line because it tends to make a more efficient process. With that setup, you can add changesets and then run liquibase update without going through an entire application startup or even running your tests. You could set it to automatically run on test execution, but the update process is usually infrequent enough that it is better to avoid the liquibase update overhead on every test execution. It is still very helpful to include in your application's spring setup so that in QA and production you don't have to remember to manually update the database, it is just automatically kept up to date.