log4net hierarchy and logging levels

Question

This site says     Loggers may be assigned levels  Levels are instances of the log4net Core Level class  The following levels are defined in order of increasing priority          ALL   DEBUG   INFO   WARN   ERROR   FATAL   OFF      DEBUG seems to have lowest priority and ERROR is higher   Question   If I set Min and Max example DEBUG and ERROR it prints everthing DEBUG  INFO  WARN and ERROR  Without use of min and max filter  If I specify ERROR  Logging level   ERROR  Will it include DEBUG  INFO  amp  WARN     lt filter type  log4net Filter LevelRangeFilter  gt        lt param name  LevelMin  value  ERROR   gt        lt param name  LevelMax  value  ERROR   gt    lt  filter gt    Instead of min and max filter  Is it possible to configure a level and include all other levels below it for logging   Example - Set level as Error it will include DEBUG  INFO  WARN and ERROR  Is this possible with log4net   Posting log4net config based on one of comments         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 debug  true  gt     lt appender name  LogFileAppender  type  log4net Appender FileAppender  gt           lt layout type  log4net Layout XMLLayout    gt  -- gt           lt param name  File  value  TestLog log    gt           lt param name  AppendToFile  value  false    gt           lt layout type  log4net Layout PatternLayout  gt               lt header type  log4net Util PatternString  value   START LOG   newline    gt               lt footer type  log4net Util PatternString  value   END LOG   newline    gt               lt conversionPattern value   d   t   -5p -  m n    gt           lt  layout gt           lt filter type  log4net Filter LevelRangeFilter  gt               lt param name  LevelMin  value  DEBUG   gt               lt param name  LevelMax  value  ERROR   gt           lt  filter gt       lt  appender gt   lt root gt           lt level value  ALL    gt           lt appender-ref ref  LogFileAppender    gt       lt  root gt       lt logger name  log4NetExample  gt           lt  --  lt appender-ref ref  B    gt  -- gt           lt level value  ALL    gt           lt appender-ref ref  LogFileAppender    gt       lt  logger gt   lt  log4net gt

User · Answer

Here is some code telling about priority of all log4net levels:

TraceLevel(Level.All); //-2147483648

TraceLevel(Level.Verbose);   //  10 000
TraceLevel(Level.Finest);    //  10 000
    
TraceLevel(Level.Trace);     //  20 000
TraceLevel(Level.Finer);     //  20 000
    
TraceLevel(Level.Debug);     //  30 000
TraceLevel(Level.Fine);      //  30 000
    
TraceLevel(Level.Info);      //  40 000
TraceLevel(Level.Notice);    //  50 000
    
TraceLevel(Level.Warn);      //  60 000
TraceLevel(Level.Error);     //  70 000
TraceLevel(Level.Severe);    //  80 000
TraceLevel(Level.Critical);  //  90 000
TraceLevel(Level.Alert);     // 100 000
TraceLevel(Level.Fatal);     // 110 000
TraceLevel(Level.Emergency); // 120 000
    
TraceLevel(Level.Off); //2147483647


private static void TraceLevel(log4net.Core.Level level)
{
   Debug.WriteLine("{0} = {1}", level, level.Value);
}

User · Answer

Its true the official documentation  Apache log4net    Manual - Introduction  states there are the following levels      ALL DEBUG INFO WARN ERROR FATAL OFF       but oddly when I view assembly log4net dll  v1 2 15 0 sealed class log4net Core Level I see the following levels defined     public static readonly Level Alert  public static readonly Level All  public static readonly Level Critical  public static readonly Level Debug  public static readonly Level Emergency  public static readonly Level Error  public static readonly Level Fatal  public static readonly Level Fine  public static readonly Level Finer  public static readonly Level Finest  public static readonly Level Info  public static readonly Level Log4Net Debug  public static readonly Level Notice  public static readonly Level Off  public static readonly Level Severe  public static readonly Level Trace  public static readonly Level Verbose  public static readonly Level Warn    I have been using TRACE in conjunction with PostSharp OnBoundaryEntry and OnBoundaryExit for a long time   I wonder why these other levels are not in the documentation   Furthermore  what is the true priority of all these levels

User · Answer

DEBUG will show all messages  INFO all besides DEBUG messages  and so on  Usually one uses either INFO or WARN  This dependens on the company policy

User · Answer

As others have noted  it is usually preferable to specify a minimum logging level to log that level and any others more severe than it  It seems like you are just thinking about the logging levels backwards   However  if you want more fine-grained control over logging individual levels  you can tell log4net to log only one or more specific levels using the following syntax    lt filter type  log4net Filter LevelMatchFilter  gt     lt levelToMatch value  WARN   gt   lt  filter gt    Or to exclude a specific logging level by adding a  deny  node to the filter   You can stack multiple filters together to specify multiple levels  For instance  if you wanted only WARN and FATAL levels  If the levels you wanted were consecutive  then the LevelRangeFilter is more appropriate   Reference Doc  log4net Filter LevelMatchFilter  If the other answers haven t given you enough information  hopefully this will help you get what you want out of log4net

User · Answer

For most applications you would like to set a minimum level but not a maximum level   For example  when debugging your code set the minimum level to DEBUG  and in production set it to WARN

User · Answer

Try like this  it worked for me    lt root gt     lt  -- lt level value  ALL    gt -- gt     lt level value  ERROR    gt     lt level value  INFO    gt     lt level value  WARN    gt        lt  root gt    This logs 3 types of errors - error  info  and warning

User · Answer

This might help to understand what is recorded at what level Loggers may be assigned levels  Levels are instances of the log4net Core Level class  The following levels are defined in order of increasing severity - Log Level                        Number of levels recorded for each setting level       ALL    DEBUG   INFO    WARN    ERROR   FATAL   OFF    All                            DEBUG     DEBUG                      INFO      INFO      INFO                   WARN      WARN      WARN      WARN               ERROR     ERROR     ERROR     ERROR     ERROR          FATAL     FATAL     FATAL     FATAL     FATAL     FATAL      OFF       OFF       OFF       OFF       OFF       OFF       OFF

[c#] log4net hierarchy and logging levels

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