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nebollogger [2020/02/22 23:06] – external edit 127.0.0.1nebollogger [2021/11/30 02:13] (current) – nebol
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 ==== NebolLogger ==== ==== NebolLogger ====
  
-<documentation not yet available>+NebolLogger is a C# package for quick and simple logging to database, file, or other destinations. 
 + 
 +See the nuget page at https://nuget.nebol.se for version history etc. 
 + 
 +=== Quick example to give you an idea of how it works === 
 + 
 +<code csharp> 
 +// First create the destination for the log output:  
 +var dailyfile = new Destination_File(@"C:\TEMP","NebolLoggerDemo", "log", Rotation.Daily);  
 + 
 +// adding the destination to the logger  
 +Logger.Instance.Destinations.Add(dailyfile);  
 + 
 +// while we're at it, let's output to the console as well, but only if it's an error or worse  
 +var console = new Destination_Console();  
 +console.Filters.Add(new Filter_Level(LogType.error));  
 +Logger.Instance.Destinations.Add(console);  
 + 
 +// now we can use the logger in our program, this line will appear only in the file  
 +Logger.Instance.Trace("Testing the new logger, it's working nicely!");  
 + 
 +// this line will appear in both the file and in the console  
 +Logger.Instance.Error("Oops, something went wrong!"); 
 +</code> 
 + 
 +=== What information is contained in a log entry? === 
 + 
 +  * Type - the LogType aka "Level" of the entry, an indication of its importance 
 +  * Date  - the exact DateTime when the entry was created 
 +  * Context - the context of the message, usually the name of the method where it was created 
 +  * Line - the line number in the sourcecode where it was created 
 +  * Machine - a Machine object containing Name of the machine and an IP address 
 +  * Application - an Application object containing the name of the application 
 +  * Component - a Component object containing the entire path of the sourcecode file 
 + 
 +=== Levels === 
 + 
 +Each message that is logged has one of these the levels of importance: 
 + 
 +  * Trace - least important - use this if you just want to follow the flow of your program 
 +  * Debug 
 +  * Information 
 +  * Notice 
 +  * Warning 
 +  * Error 
 +  * Critical 
 +  * Fatal - most important - the most severe kind of error 
 + 
 +=== Destinations === 
 + 
 +== Destination_Console - outputs to console (stdout) == 
 + 
 +<code csharp> 
 +var dest =  new Destination_Console(); 
 +</code> 
 + 
 +==Destination_ColorConsole - outputs to console (stdout) but with color (depending on level) == 
 + 
 +<code csharp> 
 +var dest =  new Destination_ColorConsole(); 
 +</code> 
 + 
 +== Destination_File - outputs to file == 
 + 
 +<code csharp> 
 +var dest = new Destination_File(string folder,string suffix = "log", Rotation file_rolation = Rotation.None, Rotation folder_rotation = Rotation.None); 
 +</code> 
 + 
 +Rotation can be : None, Hourly, Daily, Monthly, Yearly 
 + 
 +== Destination_Memory - outputs to memory ie the data is lost at application exit == 
 + 
 +<code csharp> 
 +var dest = new Destination_Memory(); 
 +</code> 
 + 
 +== Destination_Forwarder - forwards the output to one or more destinations == 
 + 
 +<code csharp> 
 +var dest = new Destination_Forwarder(dest1, dest2, dest3...); 
 +</code> 
 + 
 +== Destination_Buffer - outputs to a memory buffer that flushes its contents to an other destination after a limit has been reached == 
 + 
 +<code csharp> 
 +var dest = new Destination_Buffer(Destination dest, buffer_count = 100); 
 +</code> 
 + 
 +== Create a custom destination == 
 + 
 +To create a custom destination, create a class that inherits from Destination, then override the Write(Entry entry) method. That's the method that is called to perform the actual writing of the entry to the destination. 
 + 
 +You may also override the Write(List<Entry> entries) if you want to provide special logic to handle writing a list of entries all at once. Otherwise the Write(Entry entry) method is called once for every item in the list. 
 + 
 +=== Customization === 
 + 
 +The output format can be customized using Filters and using the FormattingDelegate delegate. You could also write your own class by inheriting from Destination. 
 + 
 +Example on customizing output format using the delegate: 
 + 
 +<code csharp> 
 +dest.FormattingDelegate = new NebolLoggerFormattingDelegate(item => 
 + item.Date.ToString("yyyy-MM-dd HH:mm:ss ") 
 + + Entry.GetLogLevelAsText(item.Type) 
 + + " " 
 + + item.Context 
 + + ": " 
 + + item.Message 
 +); 
 +</code> 
 + 
 +For console output this might be desired formatting: 
 + 
 +<code csharp> 
 +dest.FormattingDelegate = new NebolLoggerFormattingDelegate(item => 
 + item.Date.ToString("HH:mm:ss") 
 + + " : " 
 + + item.Message 
 +); 
 +</code> 
 + 
 + 
 +The method Entry.GetLogLevelAsText(item.Type) will return the 5 char length level text ie "TRACE" or "INFO " 
 +The method Entry.GetLogLevelAsTrimmedText(item.Type) will remove any whitespace ie "TRACE" or "INFO" 
 + 
 +=== Filters === 
 + 
 +== Filter_Level - limit output by level == 
 + 
 +<code csharp> 
 +// this will create a new Filter_Level that limits output to messages of level Error (or higher/worse!) 
 +var filter = new Filter_Level(LogType.error); 
 + 
 +// now attach the filter to a destination 
 +dest.Filters.Add(filter); 
 +</code> 
 + 
 +== Filter_Context - limit output by context == 
 + 
 +<code csharp> 
 +// create a context filter that accepts only context that contains "Main" 
 +var filter = new Filter_Context("Main"); 
 +</code> 
 + 
 + 
 +== Filter_Message - limit output by message == 
 + 
 +<code csharp> 
 +// create a message filter that accepts only messages containing the string "localhost" 
 +var filter = new Filter_Message("localhost"); 
 +</code> 
 + 
 + 
 +== Create a custom filter == 
 + 
 +You can also create your own filter by inheriting from Filter and overriding the Match() method. As an example, here is the complete code for Filter_Context: 
 + 
 +<code csharp> 
 +public class Filter_Context : Filter 
 +{ 
 + public string Context { get; set; } 
 + 
 + public Filter_Context(string context) 
 + { 
 + Context = context; 
 + } 
 + 
 + public override bool Match(Entry entry) 
 + { 
 + return (entry.Context.Contains(Context)); 
 + } 
 +} 
 +</code> 
 + 
 +=== Logging unhandled exceptions === 
 + 
 +To log unhandled exceptions in .NET Framework, add this class: 
 + 
 +<code csharp> 
 +public class NebolUnhandledExceptionLogger : ExceptionLogger 
 +{ 
 + public override void Log(ExceptionLoggerContext context) 
 + { 
 + Logger.Instance.Error(context.Exception.ToString()); 
 + } 
 +} 
 +</code> 
 + 
 +and this line in WebApiConfig.Register(): 
 + 
 +<code csharp> 
 +config.Services.Replace(typeof(IExceptionLogger), new NebolUnhandledExceptionLogger()); 
 +</code> 
 + 
 + 
 +and in .NET Core: 
 + 
 +<code csharp> 
 +public class NebolErrorHandlingFilter : ExceptionFilterAttribute 
 +{ 
 +    public override void OnException(ExceptionContext context) 
 +    { 
 +        var exception = context.Exception; 
 +        Logger.Instance.Error(context.Exception.ToString()); 
 + 
 +        context.ExceptionHandled = true; //optional  
 +    } 
 +} 
 +</code> 
 + 
 +then add the filter in Startup.cs ConfigureServices(): 
 + 
 +<code csharp> 
 +options.Filters.Add(new NebolErrorHandlingFilter()); 
 +</code> 
 + 
 + 
 + 
 + 
 + 
 +=== Related packages === 
 + 
 +  * [[NebolLogger.EntityFramework]] 
 +  * [[NebolLogger.Controller]] 
 +  * [[NebolLogger.Mailer]] 
 +  * [[NebolLogger.PushBullet]] 
 +  * [[NebolLogger.SharpRepository]] 
 + 
 + 
 +OBSOLETE! 
 + 
 +NebolLogger.EntityFramework.Core - for logging to database using .NET Core 
 + 
 +OBSOLETE!  .NET Core is now supported in [[NebolLogger.EntityFramework]] 
 + 
nebollogger.1582409216.txt.gz · Last modified: 2020/02/22 23:06 by 127.0.0.1

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