ksdvishnukumar / logging-to-application-insight-in-asp.net-core

My experience in making a generic ILogFactory and logging to Azure Application Insight.

Logging in ASP.NET Core using ILoggerFactory-pattern to Azure Application Insight

Disclaimer: Images and steps used in this example may change over time, but may be a good reference.

Goal

Short answer: Make logging great again

Slightly longer answer: Make the application send performance-data to Application Insight. Also make all logging from the frameworks, and logging done by me, automatically be sent to Azure for further analysis.

Packages used

• NLog - Base package for NLog
• NLog.Web:AspNetCore - Adds helpers and layout renderes for the ASP.NET core platform
• Lightinject - IOC-container
• Lightinject.Microsoft.AspNetCore.Hosting - Enables Lightinject to be used in ASP.NET core applications
• Microsoft.ApplicationInsight.AspNetCore - Official package for working with Azure Application Insight
• Microsoft.ApplicationInsight.NLogTarget - Allowing you to send NLog messages to Application Insight

Steps

01 - Azure

1. First we have to make ourself a Application Insight resource in Azure.

3. Fill in information about your application, and give it a descriptive name

4. Now we are almost done. Create it, and take note of the Instrumentation Key. We will use it shortly

02 - Code

This is based on the example project in this repo. It is a simple project created using the dotnet cli and this command: dotnet new webapi.

After the template is bootstrapped we need some base-files and interfaces. Big shoutout to @andmos for providing me with the base logfiles for this project.

File	What it does
ILog.cs	Is the base log-interface used when logging.
ILogFactory.cs	The abstraction of the log-factory. This gets the implemented logger from the IOC-container
Log.cs	Gets bootstrapped to log-actions for common Log Levels.
NLogFactory.cs	Implements a factory that produces logging based on NLog.
ILogFactoryInitializer	An abstraction for the builder-method that adds the logger to the ASP.Net Core-app.
NLogFactoryInitializer	Implements the .UseNLog() used in Program.cs to setup NLog for DI.

Noteable changes to the code:

Program.cs - gets logger factory initializer (wow. good name. thanks) from container and passes the WebHostBuilder to the implementet builder-method.

public static void Main(string[] args)
{
    var container = new ServiceContainer();
    var loggerFactoryInitializer = container.GetInstance<ILogFactoryInitializer>();
    var webhostBuilder = CreateWebHostBuilder(args);
    loggerFactoryInitializer.UseLogger(webhostBuilder);
    
    webhostBuilder.Build().Run();
}

ValuesController.cs - Added examples of logging. With Log Level Information and Error.

// GET api/values
[HttpGet]
public ActionResult<IEnumerable<string>> Get()
{
    var values = new []{"value1", "value2"};
    _logger.Info($"Request made, returning:{JsonConvert.SerializeObject(values)}");
    return values;
}

// GET api/values
[HttpGet("ThrowPlease")]
public IActionResult ThrowMePlox()
{
    try
    {
        throw new ArithmeticException("Dividing by 0?? Good luck");
    }
    catch (Exception e)
    {
        _logger.Error("This was bad. not good", e);
        return BadRequest();
    }
}

appsettings.json - contains the Application Insight Key for this project. This can also easily be set as an Enviromental Variable. The Application Insight framework will automatically search for this path in appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "ApplicationInsights": {
    "InstrumentationKey": "<KEY>"
  },
  "AllowedHosts": "*"
}

03 - Admire the result

Log-entries can be searched and filtered in the search-tab in Application Insight. Other performance-data can be found i Metrics.

Test the example app

# clone the project
git clone https://github.com/simonkaspersen/Logging-to-Application-Insight-in-ASP.NET-Core.git

# enter the project directory
cd Logging-to-Application-Insight-in-ASP.NET-Core

# Add your key to appsettings.json

# install dependencies
dotnet restore

# build solution
dotnet build

# Run
dotnet run

This will open the API at http://localhost:5000.

• Go to http://localhost:5000/api/values/ to test Information-logging
• Go to http://localhost:5000/api/values/throwplease to test Error-logging

Links to resources

• NLog - ASP.NET core
• NLog - Application Insight

TODO

• Deside if Pepsi Max or Coca Cola No Sugar is best
• Implement NLog
• Implement Log4Net
• Implement Serilog

Thanks to

• @andmos