FileLogger

Microsoft.Extensions.Logging file logger for .NET / ASP.NET Core / .NET Worker.

Why this one?

log file appender friendly. That means it does always write in the same (first) log file and on file roll over it moves the content into a new file. So you can use tools like Tailblazer or Advanced Log Viewer

Getting started

Install nuget package https://www.nuget.org/packages/asemin.FileLogger/

dotnet add package asemin.FileLogger

Either use application builder

using asemin.FileLogger;

var builder = Host.CreateApplicationBuilder(args);

builder.Logging.AddFile();

or use default builder

using asemin.FileLogger;

var builder = Microsoft.Extensions.Hosting.Host.CreateDefaultBuilder(args);

builder.ConfigureLogging(x => x.AddFile());

Tip: If you do not add any configuration, a default one will be used:

• Log file: /logs/<appname>.app.log and appname is the IHostEnvironment.ApplicationName
• max file size: 10 MiB
• max files: 10
• Default log level: Trace (Remember, the global log filters apply before this one)

Configuration

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    },
    "File": {
      "Files": {
        "default": {
          "File": "logs/logs.log",
          "MaxSize": 104857600,
          "MaxFiles": 100,
          "LogLevel": {
            "Default": "None",
            "MyClass.Logger": "Debug"
          }
        },
        "other": {
          "File": "%ProgramData%/My app/otherLogFile.log",
          "MaxSize": 10485760,
          "MaxFiles": 10,
          "LogLevel": {
            "MyOtherClass": "Trace",
            "Microsoft": "Debug"
          }
        }
      }
    }
  }
}

In Logging.File.Files you can add as many files loggers as you want. The names (default, other) are only used by .NET configuration. So you can make proper overrides with debug or production settings.

Property	Default	Description
File	logs/logs.log	Name of the log file. Supports relative paths, absolut paths and environment parameters expansion (e.g. %appdata%).
MaxSize	10485760 (10 MiB)	Max size of log file in bytes. If file exceeds this size a roll over will happen.
MaxFiles	10	Max number of log files. Older files get deleted first.
LogLevel	Trace	Works the same way as Microsoft global LogLevel. Warning: this one applies AFTER global one. So you cannot set the level for a message lower than the global one.

C# code

builder.Logging.AddFile(x =>
{
    x.Files = new Dictionary<string, LoggerConfig>
    {
        {
            "default",
            new LoggerConfig
            {
                File = @"C:\temp\my app\logs\logs.log",
                MaxSize = 100 * 1024 * 1024,
                MaxFiles = 25
            }
        }
    };
});

F# code

builder.Logging.AddFile(fun config ->
    config.Files <-
        dict[("default", LoggerConfig(
            File = "mylog.log",
            MaxSize = 10 * 1024 * 1024,
            MaxFiles = 17))])

TODOs

• try out in serious applications (confirmed)
• add support for different filters for each log file
• Test with Linux (confirmed)
• customize format of logged messages (date, thread, level, etc.) (does someone actually uses that?)