Question 1

How do I change the log level for a specific R package with futile.logger?

Accepted Answer

Use flog.threshold() with the package name as the logger argument, since futile.logger automatically scopes loggers to packages. For example, flog.threshold(DEBUG, name='package_name') sets debug level for that package's logs.

Question 2

futile.logger vs the logging package in R – which should I use?

Accepted Answer

futile.logger is better for log4j-style hierarchical logging and package scoping, while the logging package is simpler and more lightweight. Choose futile.logger if you need advanced features like automatic formatting or custom appenders.

Question 3

Can futile.logger log to a database or cloud service?

Accepted Answer

Yes, but it requires creating a custom appender function, as shown in the README example for URL logging. You'll need to handle the connection and write logic yourself, which adds complexity.

Question 4

How to format log messages with futile.logger for better readability?

Accepted Answer

Use the layout.format function to customize output, or choose from built-in layouts like layout.simple.parallel for process IDs. Refer to the layouts section for details on setting formats per logger.

Question 5

Does futile.logger support JSON output for logs?

Accepted Answer

Not out-of-the-box; you need to create a custom layout or appender to convert log messages to JSON. The built-in layouts focus on text formatting, so additional coding is required for structured formats.

Question 6

What's the best way to use futile.logger in a Shiny app?

Accepted Answer

Set up loggers with file appenders for persistence and use package scoping to control logs from different modules. Be mindful of performance in reactive contexts, and consider threshold adjustments to avoid overhead.

futile.logger

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