Have logging output separate from CLI output.

[bagel99]

I run tests using the "expect" tool to exercise the CLI. I would like to get logging output on a separate file descriptor from the CLI output so it can be put in a file and not confuse expect. Is this possible now, if so what source file do I tweak? If not, this would be a desirable enhancement. (This is running on Linux.)

[abtink]

@bagel99 you can use the OPENTHREAD_CONFIG_LOG_OUTPUT to specify where the log output goes to.

• OPENTHREAD_CONFIG_LOG_OUTPUT_APP will send the logs to app (CLI or NCP) - which I guess is what you have in your setup.
• OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED will use otPlatLog() which can be implemented by the platform layer.
  • OT posix platform implementation emits the log to syslog (posix/logging.cpp)

[bagel99]

So, if I understand correctly, my solution involves creating an alternate otPlatLog() in posix/platform/loggin.cpp that doesn't call vsyslog() but, for example, just calls vprintf(stderr, ...)?

[abtink]

Yes. This can work.