log multiple assemblies using log4net - c#

After lots of issues, finally I managed to configure log4net for my window service.
I am pretty new to it and today I started configuring it. I have these below doubts.
1) I need to use that into multiple assemblies. Say I have an assembly 'A' which is added as reference in assembly 'B' which is mine main assembly where I have reference of log4net.I need to log both assembly 'A' and 'B'.
2) My application is multi-threaded and use lots of thread. So is log4net is thread safe?
3) I am using this below config in my app.config. I am not much aware what’s the use of it. But I don’t want to use unnecessary parameters.
<log4net>
<root>
<level value="DEBUG"/>
<appender-ref ref="LogFileAppender"/>
</root>
<appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender">
<param name="File" value="C:\logs\log.txt"/>
<param name="AppendToFile" value="true"/>
<rollingStyle value="Size"/>
<maxSizeRollBackups value="10"/>
<maximumFileSize value="100KB"/>
<staticLogFileName value="true"/>
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%-5p%d{yyyy-MM-dd hh:mm:ss} – %m%n"/>
</layout>
</appender>
</log4net>

Use <lockingModel type="log4net.Appender.FileAppender+MinimalLock" /> under appender section. I twill increase the logging performance.
log4net is threadsafe.
<maximumFileSize value="10MB" /> //For 100 Kb configuration there will be lot of files.
<datePattern value="_yyyyMMdd" /> //It will hint the logger to create a new file per date.
Create a static class for Logger and call the static function from every assembly where you want to use.
Sample Class for logging:
public static class Logger
{
static Logger()
{
XmlConfigurator.Configure();
}
public static void Log()
{
string methodName = new System.Diagnostics.StackFrame(1, true).GetMethod().Name;
string moduleName = new System.Diagnostics.StackFrame(1, true).GetMethod().ReflectedType.FullName;
var appLog = LogManager.GetLogger(loggername);
appLog.Error(...);
}
}

that's not a problem; just use ILog as usual in assembly B.
just make sure you call Configure() once in your application's lifetime.
Yes.
I recommend familiarizing yourself with log4net. a simple google search or a look at the docs should do the trick.

<root>
<level value="DEBUG"/>
<appender-ref ref="LogFileAppender"/>
</root>
It will log only in debug mode, so make following entry in config:
<root>
<level value="ALL"/>
<appender-ref ref="LogFileAppender"/>
</root>

Related

Setting up a default log when Logger not found in Log4Net

I am using Log4Net as the logging mechanism for an application of ours. Our configuration is contained in a config file and in our code we programatically invoke which of our several loggers (mostly using FileAppenders) we want to invoke. Recently I realized that one of our log files was not being populated, and I tracked it down to a string mismatch, between the name in our configuration file and the name we were programatically invoking in our code. Because the LogManager could not find the specified logger the root was returned, which for our config is not setup to meaningfully log anywhere.
My question is, is there a way to setup log4net to allow for using specific loggers, but that will fall back to a general logger if the specified logger is not found?
For example using a configuration file like this
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
</configSections>
<log4net>
<root>
<level value="ALL" />
<appender-ref ref="ConsoleAppender" />
</root>
<logger name="TestFileLogger">
<level value="ALL" />
<appender-ref ref="TestFileAppender" />
</logger>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%d [%t] %-5p [%x] - %m%n" />
</layout>
</appender>
<appender name="TestFileAppender" type="log4net.Appender.RollingFileAppender">
<param name="File" value="TestLog" />
<param name="DatePattern" value=".yyyyMMdd".log"" />
<param name="AppendToFile" value="true" />
</appender>
</log4net>
</configuration>
And invoking the loggers in C# like this
var fileLogger = LogManager.GetLogger("TestFileLogger");
fileLogger.Info("This logs appropriately.");
var bogusLogger = LogManager.GetLogger("Bogus");
bogusLogger.Info("This should go to a general log. Bogus is not a recognized appender");
Is there a good way to log the messages from bogusLogger to some kind of general log file? My initial thought was to create a general file appender that is part of the root node, but this is very noisy as ALL log messages will be routed to this file. Is there a way to ONLY route messages that are not captured in another log file?
You could use LogManager.Exists("Bogus") to determine if the bogus-logger or your default implementation should be used.
You could create an extensionmethod on LogManager that could handle it for you.

Issue using .net 2.0 Logger Class

I have been trying to use the class located here . But I have not been able to get this to work. I obviously do not understand something correctly, But I am curious how to get that example Logger class to work.
My research has sent me towards using MSBuild but the use of MSBuild correctly is still baffeling me. Any pointers would be helpful. I have built the logger class into a .dll,and referenced it in the project as well, but that is where my research seemed to run dry with helpful information.
My goal currently is just to get the above noted logger class working so I can use my own logger class.
That class is specifically for logging MSBuild events. If you want a generic logger that has nothing to do with MSBuild look at some of these alternatives:
MS Enterprise Library - Logging Application Block
Log4Net
Elmah (designed for logging ASP.NET errors, but can be used to log other events)
NLog
Don't be afraid of using a library to do the work. In the tutorial here for log4net it's a simple seven step process to start using a fully functional and scalable logging library. I'm going to inline pieces of the tutorial just in case the link ever dies.
First you build a very simple configuration section in your App.config file:
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,Log4net"/>
</configSections>
<log4net>
<root>
<level value="DEBUG" />
<appender-ref ref="LogFileAppender" />
</root>
<appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender" >
<param name="File" value="log-file.txt" />
<param name="AppendToFile" value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10MB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
</log4net>
</configuration>
For your needs you pretty much just need to change the value of the first param named File as it's already setup to append to a text file.
Next you'll need to run the configuration in some startup method, like Application_Start or the main method of your program.
log4net.Config.XmlConfigurator.Configure();
Finally, just use it by plugging in a couple of lines:
private static readonly ILog log = LogManager.GetLogger(typeof(Bar));
... (rest of class)
... (somewhere in a method) ... log.Debug("this is the first log message");

Logging in an application

I built an application and want to use logging in my application before giving it out to a user to know the actions the user did in case before any error. I haven't used logging before, so I did a bit of study to find out good methods for the same and perhaps Trace class in .NET looks like what might help in this scenario.
Using a text file seems to be a better idea here for the logging setting a TextWriterTraceListener in the App.Config file of my project, and using in the code Trace.Writeline("Error info", "Field");
1) Even after reading good amount of content, I am not sure about good approaches for logging? Should there be different error logger and information logging files? How does logging work for specifying different types of error (such as warning, critical, error etc.?)
2) I want to use the same logfile in one of my other projects in the solution. So, do I add the same Trace Listener section in the App.Config of my project?
With a logging library (such as log4net), you can do all the things you are asking about easily. You can set up your logging in a config file to go to event log, file, console, etc (or any combination) and set the logging levels independently.
That is, you can say the file will have informationals, warnings, errors, and fatals, but the event log will log only the errors and fatals.
In general, nearly all of the logging libraries have these features. The examples below are just in terms of log4net but the same concepts apply to most logging libraries...
To get the logger in any class in your solution, you just need to ask for a logger in your class:
public MyClass
{
private static readonly ILog _log = log4net.LogManager.GetLogger(typeof(MyClass));
public void SomeMethod()
{
_log.Debug("This is a debug message.");
_log.Info("This is an informational message.");
_log.Warn("This is a warning message.");
_log.Error("This is an error message.");
_log.Fatal("This is a fatal message.");
}
}
In addition, you can filter based on the loggers, that is, you could suppress log messages from paraticular classes or only display logging messages for a subset of classes, etc.
A sample config settings block would look like this. This creates a rolling file appender (keeps several days worth of logs) and Console appender
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="c:\logs\AgentLog"/>
<appendToFile value="true"/>
<datePattern value=".yyyy-MM-dd"/>
<rollingStyle value="Date"/>
<MaxSizeRollBackups value="14"/>
<param name="StaticLogFileName" value="false"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%d{HH:mm:ss.fff} [%thread] %-5level %logger{1} - %m%n"/>
</layout>
</appender>
<appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
<mapping>
<level value="FATAL"/>
<foreColor value="Yellow"/>
<backColor value="Red, HighIntensity"/>
</mapping>
<mapping>
<level value="ERROR"/>
<foreColor value="Red, HighIntensity"/>
</mapping>
<mapping>
<level value="WARN"/>
<foreColor value="Yellow, HighIntensity"/>
</mapping>
<mapping>
<level value="INFO"/>
<foreColor value="Green, HighIntensity"/>
</mapping>
<mapping>
<level value="DEBUG"/>
<foreColor value="White"/>
</mapping>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%d{HH:mm:ss.fff} [%thread] %-5level %logger{1} - %m%n"/>
</layout>
</appender>
<root>
<level value="INFO"/>
<appender-ref ref="RollingFileAppender"/>
<appender-ref ref="ColoredConsoleAppender"/>
</root>
</log4net>

log4net not working in dll

I'm currently having issues with getting log4net to work within a particular dll. I'm currently using log4net in other dlls being called by my test app and logging is working fine within those dlls and also within my test app. It's this one particular dll that I'm having trouble with. Here is snippet of code from the dll I'm having trouble with.
//This is from ABC.dll
public class SessionFactory
{
protected static ISessionFactory sessionFactory;
private static readonly ILog log = LogManager.GetLogger(typeof(SessionFactory));
private static void Init()
{
try
{
//Read the configuration from hibernate.xml.cfg or app.config
Configuration normalConfig = new Configuration().Configure();
ConfigureNhibernateValidator(normalConfig);
log.Debug("Initializing session factory");
sessionFactory = Fluently.Configure(normalConfig)
.Mappings(m =>
m.FluentMappings
.AddFromAssemblyOf<OrderHeaderMap>()
.Conventions.AddFromAssemblyOf<PascalCaseColumnNameConvention>())
.ProxyFactoryFactory("NHibernate.ByteCode.LinFu.ProxyFactoryFactory, NHibernate.ByteCode.LinFu")
.BuildSessionFactory();
log.Debug("Finished initializing the session factory");
}
catch(Exception ex)
{
//Code not shown
}
}
}
In my test app I am calling:
log4net.Config.XmlConfigurator.Configure();
Here is my log4net configuration in my App.config file:
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
</configSections>
<log4net>
<!-- ALL|DEBUG|INFO|WARN|ERROR|FATAL|OFF -->
<root>
<level value="DEBUG"/>
<appender-ref ref="SpeedTest"/>
</root>
<!-- This is a default logger that nhibernate uses to push out all the SQL statements to-->
<logger name="NHibernate.SQL" additivity="false">
<level value="DEBUG"/>
<appender-ref ref="NHibernateConsoleLog"/>
<appender-ref ref="NHibernateFileLog"/>
</logger>
<!-- This is a default logger that nhibernate uses to push out all the debugging type information to-->
<logger name="NHibernate" additivity="false">
<level value="DEBUG"/>
<appender-ref ref="NHibernateFileLog"/>
</logger>
<appender name="NHibernateConsoleLog" type="log4net.Appender.TraceAppender">
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline"/>
</layout>
</appender>
<appender name="NHibernateFileLog" type="log4net.Appender.RollingFileAppender">
<file value="Logs/nhibernate.txt" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10MB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%d{HH:mm:ss.fff} [%t] %-5p %c - %m%n" />
</layout>
</appender>
<appender name="SpeedTest" type="log4net.Appender.RollingFileAppender">
<file value="Logs/SpeedTest.txt" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10MB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%d{HH:mm:ss.fff} [%t] %-5p %c - %m%n" />
</layout>
</appender>
</log4net>
</configuration>
Again logging is working fine within my test application using the SpeedTest appender but the logging within the above snippet of code is not working. I set breakpoints above on when it initializes the logger and it seems to hit it. I can post the log4net debug output if necessary but I didn't really see much. Just let me know if you need it and I will post.
Any suggestions as to why logging is not being recorded in the above snippet of code?
It seems that this issue was stemming from me changing the directory to all my external dependencies (log4net being one of them) awhile back in TFS. All I did was drop all my references in my visual studio project and re-add them from my new dependencies folder and everything worked as expected after this. Thanks for all those that helped here.
My suspicion would be that it isn't reading the configuration from the configuration file when you call configure.
If you add the following lines to your application, what do you see (either on the console, or in IDE output window, or by stepping through in the debugger):
var log4netConfig = ConfigurationManager.GetSection("log4net");
var log4netConfigIsNull = log4netConfig == null;
Console.WriteLine(log4netConfigIsNull);
Does it look like the configuration is actually available from the configuration file?
[Edit: in response to your comment]
If you now add another line of debug code to your app:
Console.WriteLine(log.IsDebugEnabled);
what output do you get? Does the logger think it is configured for debug logging? (I'm particularly interested in the behaviour of this in, or after, SessionFactory.Init).
The immediate thought would be that your logging code isn't getting hit, possibly due to an exception being thrown prior to your first log4net call. Can you put a log entry into a finally block, just to test that the logger works?

Log4Net issue while using RollingFileAppender

I am using log4net to perform logging in my application. I have bound my project to TFS. I have created a wrapper around log4net as below:
public static class TestLogger
{
private static readonly ILog log = LogManager.GetLogger("TestLogger");
static TestLogger()
{
log4net.Config.XmlConfigurator.Configure();
}
public static void LogInfo(string information)
{
log.Info(information);
}
public static void LogError(string erroMessage, Exception ex)
{
log.Error(erroMessage, ex);
}
public static void LogWarnings(string warningText)
{
log.Warn(warningText);
}
}
When I tried to execute the program from VS2010 I found that log file is not being created. I create another project (not bound to TFS) and perform some logging, it succeeded and created the file in bin/debug of application.
Below is my log4net configuration file.
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender, log4net">
<file value="Log.txt" />
<appendToFile value="false" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="3" />
<maximumFileSize value="1GB" />
<layout type="log4net.Layout.PatternLayout, log4net">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
</appender>
<logger name="TestLogger">
<level value="ALL" />
<appender-ref ref="RollingFileAppender" />
</logger>
</log4net>
Can anybody help in this issue?
Some troubleshooting tips:
define an absolute path to the Log file in your config file.
check the current working directory in your code (Environment.CurrentDirectory). If you're running under the VS debugger, and you haven't specified a working directory in the Debug tab of your project properties, it may well default to the current Visual Studio working directory.
I don't think being bound to TFS is relevant.
Just change this part
<appendToFile value="true" />
Maybe your application already uses some declarative configuration, which is somewhere burried in the code. Search for something like this:
[assembly: log4net.Config.XmlConfigurator(Watch=true)]
Otherwise try to get hold of the log4net repository with
log4net.LogManager.GetRepository(). It returns an object of the type ILoggerRepository. You can try to use this object to write some information about the current log4net configuration into the Console or somewhere else.
Try to turn on internal debugging as explained here. This should tell you what the problem is. If there is no output from internal debugging then you probably did not configure log4net.

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