Provide a mechanism to limit default behaviour of capturing all logging

[josephw]

I'd like some way to prevent existing test cases that generate huge amounts of logging from having performance impact.

I added slf4j-test to a large multi-module build with existing tests, successfully. Later, I noticed one test had become dramatically slower. On investigation, a third-party component was logging a huge volume at DEBUG: hundreds of thousands, repeated across tens of tests. Storing that was impacting the runtime measurably, adding minutes to that module's build. As a workaround, I identified the specific loggers (several) and added code to disable them individually using setEnabledLevelsForAllThreads().

I'd like a more general mechanism to prevent this. If possible, one that's opt-out, rather than opt-in, to avoid needing to change existing tests.

Some possible ways to implement this, with varying degrees of impact on existing tests:

• default to capturing INFO and above
• have a default limit to the number of events that will be retained
• allow setting an enable.level through slf4jtest.properties
• print a noisy alert of loggers with unexpectedly high volume
• a more general utility method to disable logging for a whole hierarchy of loggers
• a single utility method to disable all logging, and require subsequent tests to opt back in

The workaround is easy. Just a case where having this handled would have saved me some time.

[youribonnaffe]

I have a similar issue where using slf4j-test is making a ArchUnit test execution 10x slower (from ~1s to ~10s). ArchUnit is producing a lot of traces when it is scanning classes.

Having a global setting to decide which levels are captured would solve the issue. Is it something that can be considered? I'll be happy to contribute some code around it.

[valfirst]

Having a global setting to decide which levels are captured would solve the issue. Is it something that can be considered? I'll be happy to contribute some code around it.

yes, I think such option might be useful, system properties or properties file could be used for configuration. And contributions are highly welcome 😄

[josephw]

making a ArchUnit test execution 10x

I should add that the third-party component causing the problem in my case was also ArchUnit 😄.

[youribonnaffe]

Here is an attempt for this: #324
I mostly took inspiration from the existing print level setting.