How to create new loggers properly?

[autoantwort]

In my main method I create a custom logger with two sinks:

    std::vector<spdlog::sink_ptr> sinks;
    sinks.push_back(std::make_shared<spdlog::sinks::stdout_color_sink_mt>());
    sinks.push_back(std::make_shared<my_sink<std::mutex>>(...));
    auto combined_logger = std::make_shared<spdlog::logger>("main", begin(sinks), end(sinks));
    spdlog::set_default_logger(combined_logger);
    spdlog::set_level(spdlog::level::debug);
    spdlog::cfg::load_env_levels();

Then in my classes I create loggers with names for the corresponding classes like so:

EventQueue::EventQueue()
    : logger(spdlog::default_logger()->clone("EventQueue"))
{
}

My expectation was when I set the env var SPDLOG_LEVEL="debug,EventQueue=info I expected that my EventQueue logger would have the info level, but the level is debug.
Must I call spdlog::apply_logger_env_levels(logger); every time for every logger I create? This seems wrong. How should I create the loggers so that the level from the env applies?

[tt4g]

Environment variables have no effect on spdlog::logger::clone().
You should call spdlog::initialize_logger().

Example:

auto logger = spdlog::default_logger()->clone("EventQueue")
// Set log levels loaded from environment variables.
spdlog::initialize_logger(logger);

[autoantwort]

So to create a new logger with spdlog I always have to call two methods? Does it makes sense to simplify this by introducing a new method?

[tt4g]

I see no need to add an API to spdlog for a problem like this issue.
Because the purpose of spdlog::logger::clone() is to clone the existing loggers, and it is not the intended behavior to be affected by environment variables.

[autoantwort]

Ok. What is the expected way to have multiple loggers for different parts of an application which levels can be controlled by env vars and they all use a my custom sink?

[tt4g]

I think you could define a function in your project that calls the spdlog API to create a new logger based on the default logger.

[autoantwort]

Ok that is what I am doing now. I thought that is the absolute basic use case and there would be a api for it. Thank you for your fast answers and the project ❤️

My function now

std::shared_ptr<spdlog::logger> create_logger(std::string name)
{
    auto logger = spdlog::default_logger()->clone(std::move(name));
    spdlog::register_logger(logger);
    return std::move(logger);
}