Add logger

[euyniy]

Describe the feature you want

Currently std::cerr etc. are used in some files. Using logger will be more appropriate.

[thomasonzhou]

Thoughts on abseil logging https://abseil.io/docs/cpp/guides/logging?

https://github.com/google/glog is no longer being maintained

[kou]

https://github.com/google/glog is no longer being maintained

Oh! I didn't notice it.

Thoughts on abseil logging https://abseil.io/docs/cpp/guides/logging?

In general, a build system that uses Abseil is difficult to maintain...

[thomasonzhou]

In general, a build system that uses Abseil is difficult to maintain...

Yeah, it kind of pushes things towards Bazel. Maybe we would benefit a bit from Bzlmod, but I'm not sure if it's worth it to add it to core right now.

Ideally the logger would have callback support to enable https://rerun.io/docs/howto/integrations/integrate-host-loggers

[kou]

How about https://github.com/ChristianPanov/lwlog ?

Or we may want to create a simple our logger API for now something like:

namespace openarm::logger {
  class Logger {
    // ...
  };

  Logger *current = nullptr;
  void info(const std::string& message) {
    if (current) current->info(message);
  }

  void warn(const std::string& message) {
    if (current) current->warn(message);
  }

  // ...
}

We can change the implementation to wrap an existing logging library later.

[thomasonzhou]

Or we may want to create a simple our logger API for now

This would be nice, as it may be good to have options to log the can interface and/or motor id to debug more easily

[kou]

OK. Let's use our simple logger API approach for now.