maven-plugin: Support increasing maven log level

[mensinda]

Impact

• Bug fix (non-breaking change which fixes expected existing functionality)
• Enhancement/New feature (adds functionality without impacting existing logic)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

This PR adds a new property to the maven plugin, which allows increasing the log level with a new logLevel property.

Our primary use case / problem is that liquibase has a lot of INFO level logs. For instance, the Loading artifacts into URLClassLoader section is already bigger than the rest of the non-liquibase maven output for some of our projects. To solve this we want to only increase the log level of the liquibase plugin (so no mvn --quiet). Sadly, maven does not support changing the log level for a specific plugin inside the pom.xml. Thus, this PR is required.

Things to be aware of

• Impact on the codebase: relatively minimal, since there is only one new class, and the logger is changed at a central location.

Things to worry about

None

Additional Context

I am aware that there already exists the maven SLF4J logging configuration. However this does not fit our need since this is a maven installation and not project configuration.

[nvoxland]

Initial/Pre-Review Thoughts

I'm a bit torn on what I think on this PR, and don't have an off-hand answer so I'll move it along the process for more discussion.

Like you said, Maven has their built-in functionality for managing the logs and my base theory is that Liquibase should be simply plugging into the existing logging system and not trying to fight it or change it. That if we try to go our own way with the logging, it ends up with strange edge cases due to conflicts in configurations. At the same time, I get that the maven logging config has limitations on how it can be configured and how well it's documented.

I also wonder if the root problem of Our primary use case / problem is that liquibase has a lot of INFO level logs is really best solved by looking at what is at info level and fixing that? The info level should be "what a regular user would expect as CLI output" aka "reasonably significant messages that will make sense to end users and system administrators" and a lot of that sounds like it fails that test.

So I'll open it up to the larger group:

• Does fixing the log level of a few messages solve the problem best?
• Do we want to do more than rely on what maven has configured for logging?
• Is this implementation the right answer to the problems? How is it handling edge cases like "what if people are also configuring things like levels and channels in slf4j?" or "how does it work with simpler -X type log-related flags?" etc?

[mensinda]

Does fixing the log level of a few messages solve the problem best?

This would partially solve my problem:

First of all, here would be my wishlist for logs that should just be debug logs for all scenarios:

• The Loading artifacts into URLClassLoader logs here. Actually, all the info logs in this class could IMHO be downgraded to debug. My reasoning: If you are at the point to consider checking the classpath, you would have probably used mvn -X already.
• The big liquibase ASCII art log also does not add anything (even the liquibase version is already logged by maven).
• The Reading resource: logged here -- if you are wondering why your changeset did not execute use debug.

Additionally, the log level of Running Changeset: here, ChangeSet XXX ran successfully in here, and everything in between (Table FOO created, etc.) should be configurable. This is because with our setup, we generate the test database for our unittests with liquibase from scratch. We use the same liquibase scripts that we also use for our production DB. Thus, over the years we have accumulated a lot of changesets wich will be all executed each mvn clean verify run. This adds a lot of noice (the lines of liquibase loggs exceed the lines of test logs by a factor of at least 10).

Essentially, my goal is for our maven test DB workflow that liquibase only loggs a fixed number of lines, regardless of how big the classpath is and how many changesets are executed. However, changing the changeset log level for other use-cases (incremental DB updates) would certainly be a mistake.

[filipelautert]

@StevenMassaro from MDC point of view, is this change ok?

[StevenMassaro]

@StevenMassaro from MDC point of view, is this change ok?

I don't think this should have an impact. However, if someone were to decrease the log level, like to SEVERE, they may miss out on some MDC logging that they ordinarily would get with INFO/DEBUG/etc. However, that's intended functionality.

[filipelautert]

After all the reviews here this PR seems good to be moved along.

[rberezen]

This pull request introduces a new property to the liquibase-maven-plugin, enabling the ability to change the log level using the 'logLevel' property.

• Functional and test harness executions passing.
• Tested manually.

APPROVED