More advanced log configuration

[ThomasArdal]

Microsoft.Azure.Functions.Extensions brought us the first attempt of being able to configure custom logging providers in Functions. With the current solution (where I can inject an ILoggerProvider), I can configure functions to log everything to a single log output. I would like to be able to do much more advanced logging configuration, though. Being able to register multiple logging provider, decide which log levels goes into which logs, and other features like that, is an essential part of most applications today.

Ideally, logging would be configured like any other application using Microsoft.Extensions.Logging:

[assembly: FunctionsStartup(typeof(MyNamespace.Startup))]

namespace MyNamespace
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            ...
            builder.Services.AddLogging(logging =>
            {
                logging.AddConfiguration(config.GetSection("Logging"));
                logging.AddConsole();
                logging.AddDebug();
                logging.AddEventSourceLogger();
            });
        }
    }
}

[alrod]

We do not have plans to support custom logging providers in functions currently. @fabiocav, correct me if I am not right.

[fabiocav]

That is actually supported with the new DI capabilities.
The documentation here shows the explicit registration of a logger provider: https://docs.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection

We're working on more detailed documentation for this scenario

[ThomasArdal]

@fabiocav It's perfectly fine to close this issue if it isn't something you are planning to work on. But for future views on this issue, I just want to point out that logging as described in the original question isn't supported with the current DI capabilities. Unless I've misunderstood something, you can only register a logger provider but not actually log to multiple locations, configure which log levels goes where, and all of the other features of Microsoft.Extensions.Logging.

[fabiocav]

@ThomasArdal that's fair. A lot of what you've mentioned above is supported and we're lacking documentation on how to do that with what is currently exposed. Can you clarify your distinction between registering a logger provider and logging to multiple locations?

I'll reopen that as requested so we can track the documentation updates and any other potential work.

[ThomasArdal]

@fabiocav Great. I'll look out for the documentation. I was looking to do something like this, which either isnt't supported or I cannot get to work:

builder.Services.AddLogging(logging =>
{
    logging.AddConfiguration(config.GetSection("Logging"));
    logging.AddConsole();
    logging.AddDebug();
    logging.AddEventSourceLogger();
});

[kemmis]

Same here... can anyone show how to accomplish what @ThomasArdal is trying to do? Currently my logging is only going into app insights, but doesn't show up in the azure portal log window. I only see the built-in messages.