Bsim: Set log level from command-line argument

[jori-nordic]

Created from https://github.com/zephyrproject-rtos/zephyr/pull/75154#discussion_r1658529168

Not related to this PR specifically, but have we ever considered setting the log level at runtime for BSIM tests? We don't really care about memory in these, and would allow us to rerun a test with more verbosity without a recompile. The log level can simply be added as a argument in the run.sh (and similar) files.

A starting point would be implementing that for the sample bsim test. This way that pattern or library will automatically spread when people make new tests based on this sample.

https://github.com/zephyrproject-rtos/zephyr/blob/v3.7.0-rc2/tests/bsim/bluetooth/host/misc/sample_test/README.rst

[00thirdeye00]

hej @jori-nordic, I am new to zephyr and would like to work on this issue. can you please guide me and give me some information/references for my understanding.

[jori-nordic]

Hi, yes. You should familiarize yourself with BabbleSim and read this page carefully first: https://docs.zephyrproject.org/latest/develop/test/bsim.html

Then also read all the files in the sample test's directory.

Then look at how we add arguments to the tests: We register a parsing function that will set some global variables. The arguments are passed on the command-line this way

The idea is to then:

• Use the maximum log level when registering the "main" test modules. Ie replace CONFIG_APP_LOG_LEVEL with LOG_LEVEL_DBG on this line
• Set the log level at runtime, using the global variable that was set by the parsing function. Remember to set a conservative default, e.g. LOG_LEVEL_INF if the argument is not specified on the cli. This is an example of how to set the log level at runtime.

The command line for setting e.g., LOG_LEVEL_DBG would look something like this then, for the sample test: Execute "${test_exe}" -v=${verbosity_level} -s=${simulation_id} -d=0 -rs=420 -testid=dut -argstest log_level 4.

Here are the log level defines.

Happy hacking 💻