Configure Log4net to write to multiple files

Question

I d like to write log to 2 different log files from the same process   is that possible thing to do using log4net    I ll need to write separate messages to each log file  how can I write a message to a specific appender

User · Accepted Answer

Yes  just add multiple FileAppenders to your logger  For example    lt log4net gt       lt appender name  File1Appender  type  log4net Appender FileAppender  gt           lt file value  log-file-1 txt    gt           lt appendToFile value  true    gt           lt layout type  log4net Layout PatternLayout  gt               lt conversionPattern value   date  message newline    gt           lt  layout gt       lt  appender gt       lt appender name  File2Appender  type  log4net Appender FileAppender  gt           lt file value  log-file-2 txt    gt           lt appendToFile value  true    gt           lt layout type  log4net Layout PatternLayout  gt               lt conversionPattern value   date  message newline    gt           lt  layout gt       lt  appender gt        lt root gt           lt level value  DEBUG    gt           lt appender-ref ref  File1Appender    gt           lt appender-ref ref  File2Appender    gt       lt  root gt   lt  log4net gt

User · Answer

These answers were helpful  but I wanted to share my answer with both the app config part and the c  code part  so there is less guessing for the next person    lt log4net gt     lt appender name  SomeName  type  log4net Appender RollingFileAppender  gt       lt file value  c  Console txt    gt       lt appendToFile value  true    gt       lt rollingStyle value  Composite    gt       lt datePattern value  yyyyMMdd    gt       lt maxSizeRollBackups value  10    gt       lt maximumFileSize value  1MB    gt     lt  appender gt     lt appender name  Summary  type  log4net Appender FileAppender  gt       lt file value  SummaryFile log    gt       lt appendToFile value  true    gt     lt  appender gt     lt root gt       lt level value  ALL    gt       lt appender-ref ref  SomeName    gt     lt  root gt     lt logger additivity  false  name  Summary  gt       lt level value  DEBUG   gt       lt appender-ref ref  Summary    gt     lt  logger gt   lt  log4net gt    Then in code   ILog Log   LogManager GetLogger  SomeName    ILog SummaryLog   LogManager GetLogger  Summary    Log DebugFormat  Processing    SummaryLog DebugFormat  Processing2       Here c  Console txt will contain  Processing       and  SummaryFile log will contain  Processing2

User · Answer

Use below XML configuration to configure logs into two or more files   lt log4net gt       lt appender name  quot RollingLogFileAppender quot  type  quot log4net Appender RollingFileAppender quot  gt         lt file value  quot logs log txt 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 layout type  quot log4net Layout PatternLayout quot  gt                      lt conversionPattern value  quot  date   thread   level  logger -  message newline quot    gt         lt  layout gt       lt  appender gt        lt appender name  quot RollingLogFileAppender2 quot  type  quot log4net Appender RollingFileAppender quot  gt         lt file value  quot logs log1 txt 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 layout type  quot log4net Layout PatternLayout quot  gt                   lt conversionPattern value  quot  date   thread   level  logger -  message newline quot    gt         lt  layout gt       lt  appender gt       lt root gt         lt level value  quot All quot    gt         lt appender-ref ref  quot RollingLogFileAppender quot    gt       lt  root gt        lt logger additivity  quot false quot  name  quot RollingLogFileAppender2 quot  gt       lt level value  quot All quot   gt       lt appender-ref ref  quot RollingLogFileAppender2 quot    gt       lt  logger gt     lt  log4net gt   Above XML configuration logs into two different files  To get specific instance of logger programmatically  ILog logger   log4net LogManager GetLogger   quot RollingLogFileAppender2 quot     You can append two or more appender elements inside log4net root element for logging into multiples files  More info about above XML configuration structure or which appender is best for your application  read details from below links  https   logging apache org log4net release manual configuration html https   logging apache org log4net release sdk index html

User · Answer

I wanted to log all messages to root logger  and to have a separate log with errors  here is how it can be done    lt log4net gt       lt appender name  FileAppender  type  log4net Appender FileAppender  gt           lt file value  allMessages log    gt           lt appendToFile value  true    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  ErrorsFileAppender  type  log4net Appender FileAppender  gt           lt file value  errorsLog log    gt           lt appendToFile value  true    gt           lt layout type  log4net Layout PatternLayout  gt               lt conversionPattern value   date   -5level  logger  -  message newline    gt           lt  layout gt           lt filter type  log4net Filter LevelRangeFilter  gt               lt levelMin value  ERROR    gt               lt levelMax value  FATAL    gt           lt  filter gt       lt  appender gt        lt root gt           lt level value  ALL    gt           lt appender-ref ref  FileAppender    gt           lt appender-ref ref  ErrorsFileAppender    gt       lt  root gt   lt  log4net gt    Notice the use of filter element

User · Answer

Vinay is correct  In answer to your comment in his answer  one way you can do it is as follows    lt root gt       lt level value  ALL    gt       lt appender-ref ref  File1Appender    gt   lt  root gt   lt logger name  SomeName  gt       lt level value  ALL    gt       lt appender-ref ref  File1Appender2    gt   lt  logger gt    This is how I have done it in the past  Then something like this for the other log   private static readonly ILog otherLog   LogManager GetLogger  SomeName      And you can get your normal logger as follows   private static readonly ILog log   LogManager GetLogger MethodBase GetCurrentMethod   DeclaringType     Read the loggers and appenders section of the documentation to understand how this works

[log4net] Configure Log4net to write to multiple files

Examples related to log4net