Pass a variable to an SQL changelog at runtime

General Discussion
1

Hi, I’m using the Liquibase Java API (version 4.25.1) for change management. In my SQL changelog, I have placeholders for specific properties, like so:

CREATE SCHEMA IF NOT EXISTS ${schemaName};

How can I, through the Liquibase Java API, make the desired properties available for use? Is this even possible? I have not seen any examples for the API, only for the CLI.

Below is my sample changelog and API code:

--liquibase formatted sql

--changeset dm:create-schema-sample context:"dev" failOnError:true
CREATE SCHEMA IF NOT EXISTS ${schemaName};

try (Connection connection = DriverManager.getConnection(url, user, password)) {
    Map<String, Object> config = new HashMap<>();
    Scope.child(config, () -> {
        JdbcConnection jdbcConnection = new JdbcConnection(connection);
        Database database = DatabaseFactory.getInstance().findCorrectDatabaseImplementation(jdbcConnection);
        CommandScope commandScope = new CommandScope(COMMAND_NAME);
        commandScope.addArgumentValue(CONTEXTS_ARG, "dev");
        commandScope.addArgumentValue(CHANGELOG_FILE_ARG, "/database/changelog.sql");
        commandScope.addArgumentValue(DATABASE_ARG, database);
        commandScope.execute();
    });
} catch (Exception e) {
    throw new RuntimeException(e);
}

I have tried a few different approaches, but the placeholder is never replaced by the actual property.

2

You can pass the property by specifying an environment variable or a Java system property.

This works for me:

java -DschemaName=NewSchema -classpath .:liquibase-core.jar:postgresql-42.0.6.jar TestClass

schemaName=MY_SCHEMA java -classpath .:liquibase-core.jar:postgresql-42.0.6.jar TestClass

3

Thanks for your answer. I’m running the code from AWS in a Lambda function, so unfortunately I can’t use your suggestions. Properties would have to be passed on in some other way, specifically through the Java API

4

Another option is to use the ChangeLogParameters object. You can create an instance of this type, set your property, and then pass it to the update command, like this:


        Scope.child(config, () -> {
            JdbcConnection jdbcConnection = new JdbcConnection(connection);
            Database database = DatabaseFactory.getInstance().findCorrectDatabaseImplementation(jdbcConnection);
            ChangeLogParameters changelogParameters = new ChangeLogParameters(database);
            changelogParameters.set("schemaName", "newSchema");
            CommandScope commandScope = new CommandScope(UpdateCommandStep.COMMAND_NAME);
            commandScope.addArgumentValue(UpdateCommandStep.CONTEXTS_ARG, "dev");
            commandScope.addArgumentValue(UpdateCommandStep.CHANGELOG_FILE_ARG, "/database/changelog.sql");
            commandScope.addArgumentValue(DbUrlConnectionArgumentsCommandStep.DATABASE_ARG, database);
            commandScope.addArgumentValue(DatabaseChangelogCommandStep.CHANGELOG_PARAMETERS, changelogParameters);**
            commandScope.execute();
        });
1 Like
5

@wwillard Amazing! That was exactly what I was looking for! :slight_smile: Thank you!