Logging framework for Flank

[bootstraponline]

Use what ktor is using for logging. Add --debug flag and debug: true option in flank yaml.

• SLF4J - https://www.slf4j.org/
• https://ktor.io/servers/logging.html

print detected macOS version in FtlConstants.kt

val macOS: Boolean = (System.getProperty("os.name") ?: "").toLowerCase().indexOf("mac") >= 0

if a mac is detected as linux then sharding may fail (if the bundled nm binary isn't up to date).

[valeraz]

This lib on top of slf4j seems to be pretty popular: https://github.com/MicroUtils/kotlin-logging

[bootstraponline]

MicroUtils/kotlin-logging looks great

[bootstraponline]

https://github.com/google/flogger

[jan-goral]

Hi @bootstraponline , I need some clarifications if debug option should work for any command or only for android run and ios run. I am asking because the first option sound much more reasonable, but it also brings much more changes in implementation.
For example, if debug flag should work for all commands and can be passed from cli and also from config file, it requires to handle configuration file in Main instead of AndroidRunCommand and AndroidRunCommand. It will also change order of cli args --config flag will be first before any other command.
The simplest solution to achieve first option without doing any changes with handling configuration files, can be allowing debug flag only by cli. Correct me if I am wrong.

[bootstraponline]

I think allowing debug flag only by CLI is fine. I like going with the simplest possible solution first. We can always add complexity later if it's truly necessary.