How To Use Log4Net In ASP.NET Core Application

Ankit Mori

7y296.7k1625Blog

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Sedigheh Efaf4y ago
Hi Ankit, several appenders are defined in log4net.config, each of which contains a series of log files. How can I read all these files in a loop or something?
chinnarasu chinnarasu4y ago
Email not receive while using log4net in .net core web api
Aafaan Jii4y ago
Can you help me setup log4net in Winforms (dotnet core) and also making a simple paint like application in Winforms, which should be drawing basic shapes like - rectangle, ellipse, line, select & move shapes , draw text , save , save as, redo, undo
ali jbry4y ago
Where did u use this logger class exactly ???
gaurav agarwal5y ago
Can you please guide how to use thig logging in controller? Do I need to register this Logger class somewhere??
- Vuyo Nyembezi5y ago
  Use dependency injection like calling a repo class
Syed Khaleel6y ago
Good Article..could be provided more information on log manager after the code
- Ankit Mori5y ago
  Yes sure let me know which type of information you require ?
colt eaves6y ago
Could someone please show me how to apply this to the MS SQL Server appender? There is absolutely no place on the internet that shows a step by step of this with Log4Net. They always use the File Appender. Please if someone could help me I would gladly compensate.
- Amal AlJohari5y ago
  You can find it in this video, Tim covered everything, even the MS SQLServer https://www.youtube.com/watch?v=2lAdQ_QwNww
pramod Singh6y ago
Bhai Shabeb,Could you give example of "ADO.NET Appender -This appender will write to a Database.". i think that it is not supported by .net core.Correct me if i am wrong
VISAKH S7y ago
Try installing this package also Microsoft.Extensions.Logging.Log4Net.AspNetCore. It Worked for me.
Mihai Sacelean7y ago
What namespace are you using, I do not have this method loggerFactory.AddLog4Net();
Anand Mathur7y ago
Good narration with lucrative approach.
Laxmidhar Sahoo7y ago
Thanks for a good naration
Rushi Mehta7y ago
Thanks for sharing information

Introduction

Logging is the heart of an application. It is very important for debugging and troubleshooting, as well as, for smoothness of the application.

With the help of logging, we can have end-to-end visibility for on-premise systems, to only give a fraction of that visibility for cloud-based systems. You can write your logs to a file on a disk or a database, and send an error email.

Install NuGet Package for Log4Net

To use Log4Net logging, first you need to add the Log4Net plugin. For adding the plugin, you can do it in two different ways.

Manage NuGet Packages.
NuGet command.

You can find the required NuGet command for Log4Net below.

PM> Install-Package log4net -Version 2.0.8

Or, you can Click Here.

Update Startup file

We need to register Log4Net middleware into the startup configure section as below.

public void Configure(IApplicationBuilder app,
IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddLog4Net();
}

Add log4net.config file

We need to click on "Add New" to add a file to your project with the name log4net.config.

Refer to the below code for log4net.config for logging into the file.

<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<lockingmodel type="log4net.Appender.FileAppender+MinimalLock">
<file value="logs/">
<datepattern value="yyyy-MM-dd hh.'txt'">
<staticlogfilename value="false">
<appendtofile value="true">
<rollingstyle value="Composite">
<maxsizerollbackups value="2">
<maximumfilesize value="15MB">
<layout type="log4net.Layout.PatternLayout">
<conversionpattern value="%level %message %date">
</conversionpattern></layout>
</maximumfilesize></maxsizerollbackups></rollingstyle></appendtofile></staticlogfilename></datepattern></file></lockingmodel></appender>
<root>
<level value="ALL">
<appender-ref ref="RollingLogFileAppender">
</appender-ref></level></root>
</log4net>

Root is neccesary in log4net.config, in which we can define the log level and appender-ref to define appender. For example - FileAppender, ConsoleAppender.

<root>
<level value="ALL">
<appender-ref ref="RollingLogFileAppender">
</appender-ref></level></root>

Layout

In Layout, we can define custom parameters as shown below.

<layout type="log4net.Layout.PatternLayout">
<conversionpattern value="%level %message %date">
</conversionpattern></layout>

Logging Levels

There are seven logging levels.

OFF - nothing gets logged (cannot be called)
FATAL
ERROR
WARN
INFO
DEBUG
ALL - everything gets logged (cannot be called)

Different Appender

Rolling File Appender - It writes to the output window or the command window.
File Appender -This appender will write to a text file.
ADO.NET Appender -This appender will write to a Database.
Console Appender-This appender performs the same functions as the file appender but with the additional option to store a certain amount of data only before starting a new log file.

Logging Manager of Log4Net

public static class Logger
{
private static readonly string LOG_CONFIG_FILE = @"log4net.config";
private static readonly log4net.ILog _log = GetLogger(typeof(Logger));
public static ILog GetLogger(Type type)
{
return LogManager.GetLogger(type);
}
public static void Debug(object message)
{
SetLog4NetConfiguration();
_log.Debug(message);
}
private static void SetLog4NetConfiguration()
{
XmlDocument log4netConfig = new XmlDocument();
log4netConfig.Load(File.OpenRead(LOG_CONFIG_FILE));
var repo = LogManager.CreateRepository(
Assembly.GetEntryAssembly(), typeof(log4net.Repository.Hierarchy.Hierarchy));
log4net.Config.XmlConfigurator.Configure(repo, log4netConfig["log4net"]);
}
}

Load and Read Log4Net Config File

You need to name your config file to be your assembly name and it needs to have the extension you specify. Here is an example.

Private static void SetLog4NetConfiguration()
{
XmlDocument log4netConfig = new XmlDocument();
log4netConfig.Load(File.OpenRead(LOG_CONFIG_FILE));
var repo = LogManager.CreateRepository(
Assembly.GetEntryAssembly(), typeof(log4net.Repository.Hierarchy.Hierarchy));
log4net.Config.XmlConfigurator.Configure(repo, log4netConfig["log4net"]);
}

For more detailed information, visit this link.

Happy Coding!!!