How to use log4net in Asp net core 2 0

Question

I configure log4net in my asp net core 2 0 application as mentioned in this article LINK   program cs  public static void Main string   args        var logRepository   LogManager GetRepository Assembly GetEntryAssembly         XmlConfigurator Configure logRepository  new FileInfo  log4net config          BuildWebHost args  Run        HomeController  public class HomeController   Controller       private static readonly log4net ILog log   log4net LogManager GetLogger typeof HomeController         public IActionResult Error                 log Info  Hello logging world             return View new ErrorViewModel   RequestId   Activity Current  Id    HttpContext TraceIdentifier               log4net config    lt  xml version  1 0  encoding  utf-8   gt   lt configuration gt     lt log4net gt       lt root gt         lt level value  ALL    gt         lt appender-ref ref  RollingFile    gt       lt  root gt       lt appender name  RollingFile  type  log4net Appender FileAppender  gt         lt file value   C  Temp app log    gt          lt layout type  log4net Layout PatternLayout  gt           lt conversionPattern value   -5p  d hh mm ss   message newline    gt         lt  layout gt       lt  appender gt     lt  log4net gt   lt  configuration gt    Unlucky   I didn t see any file generated in  C  Temp app log directory  What would be the mistake  how to configure log4net for asp net core 2 0

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Following on Irfan s answer  I have the following XML configuration on OSX with  NET Core 2 1 300 which correctly logs and appends to a   log folder and also to the console   Note the log4net config must exist in the solution root  whereas in my case  my app root is a subfolder     lt  xml version  1 0  encoding  utf-8    gt   lt log4net gt     lt appender name  ConsoleAppender  type  log4net Appender ConsoleAppender   gt         lt layout type  log4net Layout PatternLayout  gt         lt conversionPattern value   date  -5level  logger -  message newline    gt         lt  layout gt     lt  appender gt     lt appender name  RollingLogFileAppender  type  log4net Appender RollingFileAppender  gt       lt lockingModel type  log4net Appender FileAppender MinimalLock   gt       lt file value  logs     gt       lt datePattern value  yyyy-MM-dd  txt    gt       lt staticLogFileName value  false   gt       lt appendToFile value  true   gt       lt rollingStyle value  Date   gt       lt maxSizeRollBackups value  100   gt       lt maximumFileSize value  15MB   gt       lt layout type  log4net Layout PatternLayout  gt         lt conversionPattern value   date   thread   -5level App   newline  message  newline  newline   gt       lt  layout gt     lt  appender gt       lt root gt         lt level value  ALL   gt         lt appender-ref ref  RollingLogFileAppender   gt         lt appender-ref ref  ConsoleAppender   gt       lt  root gt   lt  log4net gt    Another note  the traditional way of setting the XML up within app config did not work    lt  xml version  1 0  encoding  utf-8   gt   lt configuration gt       lt configSections gt       lt section name  log4net  type  log4net Config Log4NetConfigurationSectionHandler  log4net    gt     lt  configSections gt     lt log4net gt        For some reason  the log4net node was not found when accessing the XMLDocument via log4netConfig  log4net

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You need to install the Microsoft Extensions Logging Log4Net AspNetCore NuGet package and add a log4net config-file to your application  Then this should work   public class Program       private readonly ILogger lt Program gt  logger       public Program                 var services   new ServiceCollection                AddLogging logBuilder   gt  logBuilder SetMinimumLevel LogLevel Debug                BuildServiceProvider              logger   services GetService lt ILoggerFactory gt                 AddLog4Net                CreateLogger lt Program gt                static void Main string   args                Program program   new Program             program Run             Console WriteLine   n nPress any key to continue               Console ReadKey               private void Run                 logger LogInformation  Logging is working

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I ve figured out what the issue is the namespace is ambigious in the loggerFactory AddLog4Net     Here is a brief summary of how I added log4Net to my Asp Net Core project    Add the nugget package Microsoft Extensions Logging Log4Net AspNetCore Add the log4net config file in your root application folder Open the Startup cs file and change the Configure method to add log4net support with this line loggerFactory AddLog4Net                                              First you have to import the package using Microsoft Extensions Logging  using the using statement  Here is the entire method  you have to prefix the ILoggerFactory interface with the namespace    public void Configure IApplicationBuilder app  IHostingEnvironment env  NorthwindContext context  Microsoft Extensions Logging ILoggerFactory loggerFactory                        loggerFactory AddLog4Net

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Click here to learn how to implement log4net in  NET Core 2 2  The following steps are taken from the above link  and break down how to add log4net to a  NET Core 2 2 project   First  run the following command in the Package-Manager console   Install-Package Log4Net Logging -Version 1 0 0   Then add a log4net config with the following information  please edit it to match your set up     lt  xml version  1 0  encoding  utf-8    gt   lt configuration gt     lt configSections gt       lt section name  log4net  type  log4net Config Log4NetConfigurationSectionHandler  log4net    gt     lt  configSections gt     lt log4net gt       lt appender name  FileAppender  type  log4net Appender FileAppender  gt         lt file value  logfile log    gt         lt appendToFile value  true    gt         lt layout type  log4net Layout PatternLayout  gt           lt conversionPattern value   d   t   -5p -  m n    gt         lt  layout gt       lt  appender gt       lt root gt         lt  --LogLevel  OFF  FATAL  ERROR  WARN  INFO  DEBUG  ALL -- gt         lt level value  ALL    gt         lt appender-ref ref  FileAppender    gt       lt  root gt     lt  log4net gt   lt  configuration gt    Then  add the following code into a controller  this is an example  please edit it before adding it to your controller    public ValuesController         LogFourNet SetUp Assembly GetEntryAssembly     log4net config         GET api values  HttpGet  public ActionResult lt IEnumerable lt string gt  gt  Get         LogFourNet Info this   This is Info logging        LogFourNet Debug this   This is Debug logging        LogFourNet Error this   This is Error logging            return new string      value1    value2         Then call the relevant controller action  using the above example  call  Values Get with an HTTP GET   and you will receive the output matching the following      2019-06-05 19 58 45 103  9  INFO- Log4NetLogging Project Controllers ValuesController Get 23  - This is Info logging

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I was able to respond with the following methods  1-Install-Package log4net  2-Install-Package MicroKnights Log4NetAdoNetAppender  3-Install-Package System Data SqlClient  First I Create Database and Table with this Code  CREATE DATABSE Log4netDb CREATE TABLE  dbo   Log         Id   int  IDENTITY  1  1  NOT NULL       Date   datetime  NOT NULL       Thread   varchar   255  NOT NULL       Level   varchar   50  NOT NULL       Logger   varchar   255  NOT NULL       Message   varchar   4000  NOT NULL       Exception   varchar   2000  NULL    Second  I Create log4net config File in program   This is a simple configuration with no customization on the log message   lt  xml version  quot 1 0 quot  encoding  quot utf-8 quot    gt   lt log4net debug  quot true quot  gt     lt  -- definition of the RollingLogFileAppender goes here -- gt     lt appender name  quot RollingLogFileAppender quot  type  quot log4net Appender RollingFileAppender quot  gt       lt file value  quot Logs WebApp log quot    gt       lt appendToFile value  quot true quot    gt       lt rollingStyle value  quot Size quot    gt       lt maxSizeRollBackups value  quot 10 quot    gt       lt maximumFileSize value  quot 10MB quot    gt       lt staticLogFileName value  quot true quot    gt       lt lockingModel type  quot log4net Appender FileAppender MinimalLock quot    gt       lt layout type  quot log4net Layout PatternLayout quot  gt         lt  -- Format is  date time   log level   thread  message-- gt         lt conversionPattern value  quot   date    level    thread   m n quot    gt       lt  layout gt     lt  appender gt     lt appender name  quot AdoNetAppender quot  type  quot MicroKnights Logging AdoNetAppender  MicroKnights Log4NetAdoNetAppender quot  gt       lt bufferSize value  quot 1 quot    gt       lt connectionType value  quot System Data SqlClient SqlConnection  System Data quot    gt       lt connectionStringName value  quot log4net quot    gt       lt connectionStringFile value  quot appsettings json quot    gt       lt commandText value  quot INSERT INTO Log   Date   Thread   Level   Logger   Message   VALUES   log date   thread   log level   logger   message  quot    gt       lt parameter gt         lt parameterName value  quot  log date quot    gt         lt dbType value  quot DateTime quot    gt         lt layout type  quot log4net Layout RawTimeStampLayout quot    gt       lt  parameter gt       lt parameter gt         lt parameterName value  quot  thread quot    gt         lt dbType value  quot String quot    gt         lt size value  quot 255 quot    gt         lt layout type  quot log4net Layout PatternLayout quot  gt           lt conversionPattern value  quot  thread quot    gt         lt  layout gt       lt  parameter gt       lt parameter gt         lt parameterName value  quot  log level quot    gt         lt dbType value  quot String quot    gt         lt size value  quot 50 quot    gt         lt layout type  quot log4net Layout PatternLayout quot  gt           lt conversionPattern value  quot  level quot    gt         lt  layout gt       lt  parameter gt       lt parameter gt         lt parameterName value  quot  logger quot    gt         lt dbType value  quot String quot    gt         lt size value  quot 255 quot    gt         lt layout type  quot log4net Layout PatternLayout quot  gt           lt conversionPattern value  quot  logger quot    gt         lt  layout gt       lt  parameter gt       lt parameter gt         lt parameterName value  quot  message quot    gt         lt dbType value  quot String quot    gt         lt size value  quot 4000 quot    gt         lt layout type  quot log4net Layout PatternLayout quot  gt           lt conversionPattern value  quot  message quot    gt         lt  layout gt       lt  parameter gt       lt parameter gt         lt parameterName value  quot  exception quot    gt         lt dbType value  quot String quot    gt         lt size value  quot 2000 quot    gt         lt layout type  quot log4net Layout ExceptionLayout quot    gt       lt  parameter gt     lt  appender gt     lt root gt       lt level value  quot ALL quot    gt       lt appender-ref ref  quot RollingLogFileAppender quot    gt       lt appender-ref ref  quot AdoNetAppender quot    gt     lt  root gt   lt  log4net gt   Third  Replace code below with  IHostBuilder    public static IWebHostBuilder CreateWebHostBuilder string   args    gt      WebHost CreateDefaultBuilder args       ConfigureLogging logging   gt                   clear default logging providers         logging ClearProviders            logging AddConsole              logging AddDebug            logging AddEventLog               add more providers here             UseStartup lt Startup gt      Fourth  in appsettings json insert this code       quot connectionStrings quot          quot log4net quot    quot Server MICKO-PC Database Log4netDb Trusted Connection True MultipleActiveResultSets true quot         At the end  Use these commands to enjoy logging in public class ValuesController   Controller       private static readonly ILog log   LogManager GetLogger typeof ValuesController              HttpPost      public async Task lt IActionResult gt  Login string userName  string password                log Info  quot Action start quot                        More code here             log Info  quot Action end quot                      More code here        Good luck

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I am porting a  Net Framework console app to  Net Core and found a similar issue with log files not getting created under certain circumstances  When using  quot CreateRepository quot  there appears to be a difference between  net framework and  net standard  Under  Net Framework this worked to create a unique Log instance with it s own filename using the same property from log4net config GlobalContext Properties  quot LogName quot     LogName  var loggerRepository   LogManager CreateRepository LogName   XmlConfigurator Configure loggerRepository    Under  Net Standard this didn t work and if you turn on tracing you see it can t find the configuration file  quot  config quot    It wasn t loading the previous known configuration   Once I added the configuration to the configurator it still didn t log  while not complaining about it either  To get it working under  Net Standard with similar behavior as before  this is what I did  var loggerRepository   LogManager CreateRepository LogName   XmlConfigurator Configure loggerRepository new FileInfo  quot log4net config quot     var hierarchy    Hierarchy  loggerRepository  var appender    RollingFileAppender hierarchy Root GetAppender  quot RollingLogFileAppender quot    appender File   Path Combine Directory GetCurrentDirectory     quot logs quot     quot  LogName  log quot     I didn t want to create a configuration file for every repo  so this works   Perhaps there is a better way to get the  Net Framework behavior as before and if there is please let me know below

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Still looking for a solution  I got mine from this link    All I had to do was add this two lines of code at the top of  public static void Main  method in the  program class     var logRepo   LogManager GetRepository Assembly GetEntryAssembly      XmlConfigurator Configure logRepo  new FileInfo  log4net config       Yes  you have to add    Microsoft Extensions Logging Log4Net AspNetCore using NuGet  A text file with the name of log4net config and change the property Copy to Output Directory  of the file to  Copy if Newer  or  Copy always     You can also configure your asp net core application in such a way that everything that is logged in the output console will be logged in the appender of your choice   You can also download this example code from github and see how i configured it

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I am successfully able to log a file using the following code  public static void Main string   args        XmlDocument log4netConfig   new XmlDocument        log4netConfig Load File OpenRead  log4net config         var repo   log4net LogManager CreateRepository Assembly GetEntryAssembly                   typeof log4net Repository Hierarchy Hierarchy        log4net Config XmlConfigurator Configure repo  log4netConfig  log4net          BuildWebHost args  Run        log4net config in website root   lt  xml version  1 0  encoding  utf-8    gt   lt log4net gt     lt appender name  RollingLogFileAppender  type  log4net Appender RollingFileAppender  gt       lt lockingModel type  log4net Appender FileAppender MinimalLock   gt       lt file value  C  Temp     gt       lt datePattern value  yyyy-MM-dd  txt    gt       lt staticLogFileName value  false   gt       lt appendToFile value  true   gt       lt rollingStyle value  Date   gt       lt maxSizeRollBackups value  100   gt       lt maximumFileSize value  15MB   gt       lt layout type  log4net Layout PatternLayout  gt         lt conversionPattern value   date   thread   -5level App   newline  message  newline  newline   gt       lt  layout gt     lt  appender gt       lt root gt         lt level value  ALL   gt         lt appender-ref ref  RollingLogFileAppender   gt       lt  root gt   lt  log4net gt

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There is a third-party log4net adapter for the ASP NET Core logging interface   Only thing you need to do is pass the ILoggerFactory to your Startup class  then call  loggerFactory AddLog4Net      and have a config in place  So you don t have to write any boiler-plate code   More info here

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