How do I implement custom logging providers in MvvmCross

Overview of MvvmCross Logging

MvvmCross 8 uses Microsoft.Extensions.Logging, which allows for more flexibility and compatibility with various logging providers like Serilog. This change simplifies the process of integrating third-party logging frameworks.

Implementing a Custom Logging Provider

To create a custom logging provider in MvvmCross, you need to implement the `ILoggerProvider` interface. This interface is part of the Microsoft.Extensions.Logging namespace and is responsible for creating instances of loggers.

Step 1: Implementing `ILoggerProvider`

Here's an example of how you might implement a custom logger provider:

csharp
using Microsoft.Extensions.Logging;

public class CustomLoggerProvider : ILoggerProvider
{
    public ILogger CreateLogger(string categoryName)
    {
        // Implement your custom logger creation logic here
        return new CustomLogger(categoryName);
    }

    public void Dispose()
    {
        // Dispose any resources used by the provider
    }
}

Step 2: Implementing `ILogger`

You also need to implement the `ILogger` interface for your custom logger. This interface defines methods for logging messages at different levels.

csharp
using Microsoft.Extensions.Logging;

public class CustomLogger : ILogger
{
    private readonly string _categoryName;

    public CustomLogger(string categoryName)
    {
        _categoryName = categoryName;
    }

    public IDisposable BeginScope(TState state)
    {
        // Implement scope logic if needed
        return null;
    }

    public bool IsEnabled(LogLevel logLevel)
    {
        // Determine if logging is enabled for a specific level
        return true; // For example, always enabled
    }

    public void Log(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func formatter)
    {
        // Implement your logging logic here
        // For example, write to a file or database
        Console.WriteLine($"[{logLevel}] {_categoryName} - {formatter(state, exception)}");
    }
}

Step 3: Registering the Custom Provider

In your MvvmCross setup class, you need to override methods to register your custom logging provider. Here’s how you can do it:

csharp
public class Setup : MvxWpfSetup
{
    protected override ILoggerProvider CreateLogProvider()
    {
        return new CustomLoggerProvider();
    }

    protected override ILoggerFactory CreateLogFactory()
    {
        return new LoggerFactory();
    }
}

However, for more complex scenarios or to use a specific logging framework like Serilog, you might need to configure it differently.

Using Serilog as a Custom Provider

Serilog is a popular logging framework that can be easily integrated with MvvmCross. Here’s how you can use it:

1. Install Serilog Packages: Install `Serilog` and `Serilog.Extensions.Logging` NuGet packages in your project.

2. Configure Serilog in Setup Class:

csharp
public class Setup : MvxWpfSetup
{
    protected override ILoggerProvider CreateLogProvider()
    {
        return new SerilogLoggerProvider();
    }

    protected override ILoggerFactory CreateLogFactory()
    {
        Log.Logger = new LoggerConfiguration()
            .MinimumLevel.Debug()
            // Add sinks here, e.g., WriteTo.File("log.txt")
            .CreateLogger();

        return new SerilogLoggerFactory();
    }
}

3. Add Sinks: You can add various sinks (outputs) for Serilog, such as logging to files, console, or even network destinations.

Conclusion

Implementing custom logging providers in MvvmCross involves creating a custom `ILoggerProvider` and `ILogger`, then registering them in your application's setup. For more advanced logging needs, integrating frameworks like Serilog can provide structured logging and multiple output options.