Setting Liquibase Java use changelogs outside of the classpath/jar

Question

I'm using Liquibase with Maven in a project - v4.2.0.

My changelogs are on the file system, rather than in the JAR or classpath of the project.

I'm using the following to establish my object:

liquibase = new Liquibase( changeLogFile, new FileSystemResourceAccessor(), database );

where the changelogFile is something like ~/liquibase-sql/changelog/db.changelog.xml

When I call liquibase.validate(), I get the following, after a reminder of the classpath locations:

Specifying files by absolute path was removed in Liquibase 4.0. Please use a relative path or add '/' to the classpath parameter.

I've tried various things including a file: prefix, and the file is question can be opened in terminal directly.
I have looked through the code and I'm confused by the concept of FileSystemResourceAccessor being named as such if it can only use the classpath (there's already a ClassLoaderResourceAccessor), but I can't see a way to make it work.

Based on very very old questions people have managed this before, but I assume prior to 4.0? (this works fine on 3.10.3)

Does anyone have any pointers? I've used CLI liquibase and understand the error, but I'm not sure how I can not determine the path without it being absolute, on the understanding that this would be potentially be ran on a few different machines in arbitrary locations.

This might be niche question, but thanks for any help in advance.

Answer 1

Here is what I ended up doing (for a gradle-based project):

• force the external location to actually be part of the classpath
• changed the XSD location to full URL (apparently liquibase has enough smarts to NOT fetch that from online location, but instead load from the cache of XSD files bundled with the distribution JAR.

For gradle, this meant adding some stuff to build.gradle like so:

sourceSets {
  test {
    //whatever else you have
    resources {
      srcDir 'src/test/resources'
      srcDir 'top-external-folder-of-changelog'
    }
  }
}    
dependencies {
  testImplementation files (path/to/external/folder)
}

The changelog schemaLocation attribute then looks like this:

xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.11.xsd"

Remember to adjust for your version,

My specific issues was with tests. For real environments, the liquibase scripts are applied to the database via an external (liquibase-based) tool.