ILogger implementation for ApplicationInsights

[RamjotSingh]

Original discussion at - microsoft/ApplicationInsights-aspnetcore#749

C# Console program sample

Packages installed

<ItemGroup>
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.ApplicationInsights" Version="2.8.1-build39946" />
    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="2.1.0" />
  </ItemGroup>

class Program
    {
        static void Main(string[] args)
        {
            // Create DI container.
            IServiceCollection services = new ServiceCollection();
            
            // Add the logging pipelines to use. We are using Console and AI and configuring them both.
            services.AddLogging(loggingBuilder =>
            {
                loggingBuilder.AddApplicationInsights("--YourAIKeyHere--");

                loggingBuilder.AddConsole();
            });

            // Build ServiceProvider.
            IServiceProvider serviceProvider = services.BuildServiceProvider();

            ILogger<Program> logger = serviceProvider.GetRequiredService<ILogger<Program>>();

            // Begin a new scope. This is optional. Epecially in case of AspNetCore request info is already
            // present in scope.
            using (logger.BeginScope(new Dictionary<string, object> { { "Method", nameof(Main) } }))
            {
                logger.LogInformation("Logger is working");
            }
        }
    }

[RamjotSingh]

Trying to collect all the issues which are logged across various repos. Please feel free to reference other issues here.

microsoft/ApplicationInsights-aspnetcore#491
microsoft/ApplicationInsights-aspnetcore#749
microsoft/ApplicationInsights-aspnetcore#783

[lmolkova]

@RamjotSingh we have an ongoing conversation with Asp.Net Core team on the high-level design of this feature . There are many things to consider: scopes support and meaning in AppInsights, sampling, common ids.

We also have ILogger implementation in AspNEtCore repo: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/ed794ae3a0150715d76432c7417aa93c334126af/src/Microsoft.ApplicationInsights.AspNetCore/Logging/Implementation/ApplicationInsightsLogger.cs

So could we hold this on until we finalize the design?

cc @SergeyKanzhelev

[RamjotSingh]

@lmolkova Oh ok that's cool. I thought that this was sitting on cold plate so I ended up picking it up. The ILogger implementation I have done is actually based on what @SergeyKanzhelev wrote in his private branch (which was in turn based on AI-ASPNetCore repo). If you feel this is getting picked up I can close the PR for now.

Let me know what you think.

[cijothomas]

@RamjotSingh Thanks for your effort here - we definitely want to take it. We may change implementation later based on discussions with asp.net core team, but moving this to logging is the right thing to do now!
Will review this shortly

[cijothomas]

Once we merge this and ship a new nuget package from this repo (Microsoft.ApplicationInsights.ILoggerProvider or Microsoft.Extensions.Logging.ApplicationInsights), the extension methods on application insights asp.net core sdk can be marked obsolete to be removed in the next major version bump. It'll still contain the duplicate code for ApplicationInsightsLogger etc.

User who want to use ILogger with ApplicationInsights should use this new package, and new extension methods.

[davidfowl]

I'm hope it would look something like this:

var services = new ServiceCollection();            
services.AddLogging(loggingBuilder =>
{
    loggingBuilder.AddApplicationInsights("--YourAIKeyHere--");
});

var serviceProvider = services.BuildServiceProvider();
var loggerFactory = serviceProvider.GetRequiredService<ILoggerFactory>();
var logger = loggerFactory.CreateLogger("MyCategory");

using (logger.BeginScope("Test"))
{
    logger.LogInformation("Logger is working");
}

in 3.0 it'll look like this:

var loggerFactory = LoggerFactory.Create(builder => 
{
    builder.AddApplicationInsights("--YourAIKeyHere--");
});

var logger = loggerFactory.CreateLogger("MyCategory");

using (logger.BeginScope("Test"))
{
    logger.LogInformation("Logger is working");
}

More advanced options should look like this:

var loggerFactory = LoggerFactory.Create(builder => 
{
    builder.AddApplicationInsights(options => 
    {
        options.InstrumentationKey  = "--YourAIKeyHere--";
    });
});

var logger = loggerFactory.CreateLogger("MyCategory");
using (logger.BeginScope("Test"))
{
    logger.LogInformation("Logger is working");
}

Generic Host (3.0 APIs):

 var host = Host.CreateHostBuilder()
            .ConfigureLogging(logging =>
            {
                logging.AddApplicationInsights("--YourAIKeyHere--");
            })
            .Build();

host.RunAsync();

[pakrym]

LGTM

[cijothomas]

left few comments.. Most importantly - i cannot see how a user would setup application insights to log only logs above a given level ? Loglevel seems missing..
Other than that (and few minor comments), looks good!

[RamjotSingh]

@cijothomas Here is how someone can configure ApplicationInsights to only log above a specific level.

               loggingBuilder.AddFilter((logLevel) =>
                {
                    if (logLevel > LogLevel.Information)
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }).AddApplicationInsights();

I think this is what @pakrym talked about when referring to Filtering.

[davidfowl]

Yes filtering is built into the factory as a first class citizen.

[lmolkova]

@RamjotSingh we fixed build issue (#243) and are going to ship it in next beta release. Would you mind re-enabling analyzers nugets as a separate PR?

[lmolkova]

@RamjotSingh thanks a lot for the contribution! 🥇