Configuring logging

This guide describes how to enable and configure logging for Flexmonster Data Server as a DLL.

Note Instructions from this guide are for the projects based on ASP.NET Core version 3.1 or ASP.NET versions from 5 to 6.

Enable logging

By default, the Data Server relies on the project-wide logging settings. If logging is disabled in your project, the Data Server does not log. If logging is enabled, the Data Server logs at the default log level and higher.

The Data Server does not require any specific configurations or changes to its code to start logging. It automatically logs to the used logging provider.

Where the Data Server’s logs can be found

It depends on the logging provider used in your project. If a built-in provider is used, logs are displayed in Visual Studio or in the console. If you are using a third-party or custom provider, the Data Server’s logs are stored in a location specified in the provider’s configurations.

Configure log levels

Ways to configure log levels depend on a logging provider used in your project:

• Built-in providers
• Third-party and custom providers

Built-in providers

With built-in logging providers, you can configure log levels for the Data Server via the configuration file (e.g., appsettings.json). In the file, specify the Flexmonster.DataServer.Core category under the LogLevel property of the used provider:

{
  "Logging": {
    "Debug": {
      "LogLevel": {
        // Other settings
        "Flexmonster.DataServer.Core": "Warning",
        // Other settings
      }
    }
  }
}

In the above code snippet, Flexmonster.DataServer.Core is set to "Warning". This means you will see the Data Server’s logs at the level Warning and higher.

Learn more about configuring built-in providers: Configure logging.

Third-party and custom logging providers

If your project uses one of the supported third-party providers, log levels for the Data Server should be configured within that provider. Use the Flexmonster.DataServer.Core category to configure log levels.

The same applies to custom logging providers that implement the ILoggerProvider interface.

Customize the Data Server's logging

If needed, you can customize the Data Server's logging by creating your implementation of the IFlexmonsterLogger interface:

Step 1. In your project, create a C# class (e.g., FlexmonsterLogger.cs).

Step 2. Open the created file and import Flexmonster.DataServer.Core.Logger:

using Flexmonster.DataServer.Core.Logger;

Step 3. Implement the IFlexmonsterLogger interface by implementing the LogDebug, LogInformation, LogWarning, LogError, and LogCritical methods.

Here's a sample implementation:

using Flexmonster.DataServer.Core.Logger;
using Microsoft.Extensions.Logging;
using System;

namespace FDS_Project
{
  public class FlexmonsterLogger<T> : IFlexmonsterLogger<T>
  {
    /* You can use any logger type aside from ILogger */
    private readonly ILogger<T> _logger;

    public FlexmonsterLogger(ILogger<T> logger)
    {
      _logger = logger;
    }

    public void LogDebug(string message, params string[] args)
    {
      _logger?.LogDebug(message, args);
    }

    public void LogInformation(string message, params string[] args)
    {
      _logger?.LogInformation(message, args);
    }

    public void LogWarning(string message, params string[] args)
    {
      _logger?.LogWarning(message, args);
    }

    public void LogError(string message, params string[] args)
    {
      _logger?.LogError(message, args);
    }

    public void LogCritical(string message, params string[] args)
    {
      _logger?.LogCritical(message, args);
    }
  }
}

Step 4. In the Program.cs file, add the following lines of code to register your logger implementation:

using Flexmonster.DataServer.Core.Logger;

var builder = WebApplication.CreateBuilder(args);
// Other configurations

builder.Services.AddFlexmonsterApi();
/* Note that the logger registration should always go
   after the builder.Services.AddFlexmonsterApi() line */
builder.Services.AddSingleton(typeof(IFlexmonsterLogger<>), 
  typeof(FlexmonsterLogger<>));
// Other configurations

Now the Data Server will use your custom logger implementation.

What’s next?

You may be interested in the following articles:

• Implementing the server filter
• Implementing the custom parser
• DLL configurations reference