> To put that another way, you might not know at the time whether your function is going to be invoked from a high-throughput loop.

> Is there a nice solution to this problem?

There's two ways to do it from within the logging framework. The first way is that you can suppress duplicate messages with a filter, like the DuplicateMessageFilter [1]. It wouldn't be that hard to add a filter that looked for the message template, and could suppress based on other properties on the LoggingEvent, such as the request ID or the overall similarity of the event.

The second thing you can do is add a budget for your logger, which will only allow it to log a certain period in a window. This is something you can do with budget evaluators [2].

Depending on the layer you put over SLF4J, you can also add conditional logging [3], which puts the logic at the application layer. Under this model, you'd have a counter or circuit breaker in the condition that would short-circuit the logging.

[1] http://logback.qos.ch/manual/filters.html#DuplicateMessageFi...

[2] https://tersesystems.github.io/terse-logback/guide/budget/

[3] https://tersesystems.github.io/blindsight/usage/conditional....

I think this is mostly a result of the OOP ethos to think of actions on single objects, where each function call created a log message. This is then called in a loop.

Meanwhile the general case is actually that actions are performed on a collection of things, although this is often not obvious due to OOP design. But when working with collections it becomes obvious that log messages should be aggregates over collections ("2 out of items failed, errors: ..."). This then creates magnitudes less of logging. It's just not mainstream now.

Sounds like you don't have enough information to make a decision when developing the function so thw logging behaviour should be configurable by the user.

Yes, I suppose a simple parameter would do the job. Probably not worth anything fancy.

A parameter where? Obviously not in the code of the function itself; polluting your application code with flags such as log=true|false is obviously a no-go. Especially since logging is only one such "cross cutting concern", one of many, and you simply cannot go polluting your code with all of them because it leads to a mess.

Many Java logging systems allow you to enable/disable logging per package, but this is still not enough for a per function decision.

Logging is a hard problem.

> Many Java logging systems allow you to enable/disable logging per package, but this is still not enough for a per function decision.

I have something for that. [1]

[1] https://tersesystems.github.io/blindsight/usage/conditional....

Logging filtering is available per class in Logback [1], as well as having Markers which can target individual logging statements [2]

[1] https://stackoverflow.com/questions/46062711/show-logs-only-...

[2] https://stackoverflow.com/questions/30248169/how-to-deal-wit...

I mean there's no reason you couldn't have a thread-local override to the log level and restore it after the function call.

The fact that logging is at all intermixed with business logic I think is the main problem. I should be able to take a fully working logless program and apply different logging profiles to it. What gets logged should be a function of the person invoking the program.

Definitely. I was trying to argue something about intermixing logging with app logic :) It indeed seems to me the decision about what to log should be the caller's, not the callee's, and so it shouldn't be hardcoded within the latter.