c Best Method to create a log file

Question

I m writing a tool that s going to be check the health of workstations across a network  and will fix according to the issues it finds  I want to create a log file as the app is running through its tasks   checks on each machine  I just want to get this working on a single machine for now  but in time it will be scanning 100  machines in one go  Threaded out    What is the best way to create a log file   I was thinking of using a List lt string gt  to build up the log file in memory and then output it to a file once it had finished   I m just thinking there may be a better way of doing this

User · Accepted Answer

I would not use third party libraries  I would log to an xml file    This is a code sample that do logging to a xml file from different threads   private static readonly object Locker   new object    private static XmlDocument  doc   new XmlDocument     static void Main string   args        if  File Exists  logs txt             doc Load  logs txt        else               var root    doc CreateElement  hosts             doc AppendChild root              for  int i   0  i  lt  100  i                  new Thread new ThreadStart DoSomeWork   Start             static void DoSomeWork                   Here you will build log messages             Log  192 168 1 15    alive       static void Log string hostname  string state        lock  Locker                var el    XmlElement  doc DocumentElement AppendChild  doc CreateElement  host             el SetAttribute  Hostname   hostname           el AppendChild  doc CreateElement  State    InnerText   state           doc Save  logs txt

User · Answer

I found the SimpleLogger from heiswayi on GitHub good

User · Answer

I would recommend log4net   You would need multiple log files  So multiple file appenders  Plus you can create the file appenders dynamically   Sample Code   using log4net  using log4net Appender  using log4net Layout  using log4net Repository Hierarchy      Set the level for a named logger public static void SetLevel string loggerName  string levelName        ILog log   LogManager GetLogger loggerName       Logger l    Logger log Logger       l Level   l Hierarchy LevelMap levelName             Add an appender to a logger public static void AddAppender string loggerName  IAppender appender        ILog log   LogManager GetLogger loggerName       Logger l    Logger log Logger       l AddAppender appender         Create a new file appender public static IAppender CreateFileAppender string name  string fileName        FileAppender appender   new         FileAppender        appender Name   name      appender File   fileName      appender AppendToFile   true       PatternLayout layout   new PatternLayout        layout ConversionPattern     d   t   -5p  c   x  -  m n       layout ActivateOptions         appender Layout   layout      appender ActivateOptions         return appender        In order to set the level for a logger and add an appender reference you    can then use the following calls  SetLevel  Log4net MainForm    ALL    AddAppender  Log4net MainForm   CreateFileAppender  appenderName    fileName log         repeat as desired   Sources Good links   Log4Net  Programmatically specify multiple loggers  with multiple file appenders    Adding appenders programmatically  How to configure log4net programmatically from scratch  no config   Plus the log4net also allows to write into event log as well  Everything is configuration based  and the configuration can be loaded dynamically from xml at runtime as well   Edit 2   One way to switch log files on the fly  Log4Net configuration file supports environment variables   Environment SetEnvironmentVariable  log4netFileName    MyApp log      and in the log4net config    lt param name  File  value    log4netFileName   log  gt

User · Answer

You might want to use the Event Log   Here s how to access it from C  http   support microsoft com kb 307024 en  But whatever is the method that you will use  I d recommend to output to a file every time something is appended to the log rather than when your process exits  so you won t lose data in the case of crash or if your process is killed

User · Answer

add this config file                                                                                           lt  --Configuration for file appender-- 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 txt    gt         lt appendToFile value  true    gt         lt layout type  log4net Layout PatternLayout  gt           lt conversionPattern value   d   t   -5p   logger  -  m n    gt         lt  layout gt       lt  appender gt       lt root gt         lt level value  DEBUG    gt         lt appender-ref ref  FileAppender    gt       lt  root gt     lt  log4net gt   lt  configuration gt                                                                                           lt  --Configuration for console appender-- 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  ConsoleAppender  type  log4net Appender ConsoleAppender   gt         lt layout type  log4net Layout PatternLayout  gt           lt param name  ConversionPattern  value   d   t   -5p   logger  -  m n    gt         lt  layout gt       lt  appender gt      lt root gt         lt level value  ALL    gt         lt appender-ref ref  ConsoleAppender    gt       lt  root gt     lt  log4net gt   lt  configuration gt

User · Answer

We did a lot of research into logging  and decided that NLog was the best one to use   See http   nlog-project org   Also see log4net vs  Nlog and http   www dotnetlogging com comparison

User · Answer

Instead of using log4net which is an external library I have created my own simple class  highly customizable and easy to use  edit YOURNAMESPACEHERE with the namespace that you need    CONSOLE APP  using System  using System IO   namespace YOURNAMESPACEHERE       enum LogEvent               Info   0          Success   1          Warning   2          Error   3            internal static class Log               private static readonly string LogSession   DateTime Now ToLocalTime   ToString  quot ddMMyyyy HHmmss quot            private static readonly string LogPath   AppDomain CurrentDomain BaseDirectory    quot logs quot            internal static void Write LogEvent Level  string Message  bool ShowConsole   true  bool WritelogFile   true                        string Event   string Empty              ConsoleColor ColorEvent   Console ForegroundColor               switch  Level                                case LogEvent Info                      Event    quot INFO quot                       ColorEvent   ConsoleColor White                      break                  case LogEvent Success                      Event    quot SUCCESS quot                       ColorEvent   ConsoleColor Green                      break                  case LogEvent Warning                      Event    quot WARNING quot                       ColorEvent   ConsoleColor Yellow                      break                  case LogEvent Error                      Event    quot ERROR quot                       ColorEvent   ConsoleColor Red                      break                             if  ShowConsole                                Console ForegroundColor   ColorEvent                  Console WriteLine  quot    0     gt   1  quot   DateTime Now ToString  quot HH mm ss quot    Message                   Console ResetColor                               if  WritelogFile                                if   Directory Exists LogPath                       Directory CreateDirectory LogPath                    File AppendAllText LogPath     quot   quot    LogSession    quot  log quot   string Format  quot   0     gt   1    2  n quot   DateTime Now ToString  quot HH mm ss quot    Event  Message                                      NO CONSOLE APP  ONLY LOG   using System  using System IO   namespace YOURNAMESPACEHERE       enum LogEvent               Info   0          Success   1          Warning   2          Error   3        internal static class Log       private static readonly string LogSession   DateTime Now ToLocalTime   ToString  quot ddMMyyyy HHmmss quot        private static readonly string LogPath   AppDomain CurrentDomain BaseDirectory    quot logs quot        internal static void Write LogEvent Level  string Message                string Event   string Empty           switch  Level                        case LogEvent Info                  Event    quot INFO quot                   break              case LogEvent Success                  Event    quot SUCCESS quot                   break              case LogEvent Warning                  Event    quot WARNING quot                   break              case LogEvent Error                  Event    quot ERROR quot                   break                     if   Directory Exists LogPath               Directory CreateDirectory LogPath            File AppendAllText LogPath     quot   quot    LogSession    quot  log quot   string Format  quot   0     gt   1    2  n quot   DateTime Now ToString  quot HH mm ss quot    Event  Message             Usage   CONSOLE APP  Log Write LogEvent Info   quot Test message quot       It will print an info in your console  also will save a copy of this print in a  log file  Log Write LogEvent Warning   quot Test message quot   false      It will save the print as warning only in your  log file  Log Write LogEvent Error   quot Test message quot   true  false      It will print an error only in your console    NO CONSOLE APP  ONLY LOG   Log Write LogEvent Info   quot Test message quot       It will print an info in your  log file

User · Answer

You can use http   logging apache org  library and use a database appender to collect all your log info together

User · Answer

You can also take a look at the built-in  NET tracing facilities too  There s a set of trace listeners that allow you to output to a log file  but you can configure it to log into the Event viewer  or to a database  or all of them simultaneously    http   www codeguru com csharp  net net debugging tracing article php c5919 NET-Tracing-Tutorial htm

User · Answer

Use the Nlog http   nlog-project org   It is free and allows to write to file  database  event log and other 20  targets  The other logging framework is log4net - http   logging apache org log4net   ported from java Log4j project   Its also free   Best practices are to use common logging - http   commons apache org logging  So you can later change NLog or log4net to other logging framework

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I m using thread safe static class  Main idea is to queue the message on list and then save to log file each period of time  or each counter limit   Important   You should force save file   DirectLog SaveToFile      when you exit the program   in case that there are still some items on the list   The use is very simple  DirectLog Log  MyLogMessage   5    This is my code   using System  using System IO  using System Collections Generic   namespace Mendi             lt summary gt          class used for logging misc information to log file         written by Mendi Barel          lt  summary gt      static class DirectLog               readonly static int SAVE PERIOD   10   1000    period 10 seconds         readonly static int SAVE COUNTER   1000    save after 1000 messages         readonly static int MIN IMPORTANCE   0    log only messages with importance value  gt  MIN IMPORTANCE          readonly static string DIR LOG FILES     z  MyFolder             static string  filename   DIR LOG FILES     Log     DateTime Now ToString  yyMMdd HHmm        txt            readonly static List lt string gt   list log   new List lt string gt             readonly static object  locker   new object            static int  counter   0          static DateTime  last save   DateTime Now           public static void NewFile              new file is created because filename changed             SaveToFile                lock   locker                                  filename   DIR LOG FILES     Log     DateTime Now ToString  yyMMdd HHmm        txt                    counter   0                                  public static void Log string LogMessage  int Importance                        if  Importance  lt  MIN IMPORTANCE  return              lock   locker                                 list log Add String Format   0 HH mm ss ffff   1   2    DateTime Now  LogMessage  Importance                     counter                              TimeSpan timeDiff   DateTime Now -  last save               if   counter  gt  SAVE COUNTER    timeDiff TotalMilliseconds  gt  SAVE PERIOD                  SaveToFile                       public static void SaveToFile                         lock   locker                  if   list log Count    0                                         last save    last save   DateTime Now                      return                                lock   locker                                using  StreamWriter logfile   File AppendText  filename                                          foreach  string s in  list log  logfile WriteLine s                       logfile Flush                        logfile Close                                        list log Clear                     counter   0                   last save   DateTime Now                                    public static void ReadLog string logfile                        using  StreamReader r   File OpenText logfile                                 string line                  while   line   r ReadLine       null                                        Console WriteLine line                                     r Close

User · Answer

You could use the Apache log4net library       using System  using log4net  using log4net Config    public class MyApp          Define a static logger variable so that it references the        Logger instance named  MyApp       private static readonly ILog log   LogManager GetLogger typeof MyApp        static void Main string   args                XmlConfigurator Configure new System IO FileInfo         resources log4net config             log Info  Entering application             Console WriteLine  starting                     log Info  Entering application             log Error  Exiting application             Console WriteLine  starting

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