Log4Net RollingFileAppender doesn't write long strings - log4net

I have the following Log4Net config:
<appender name="WSLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="${APPDATA}\xxxx"/>
<evaluator type="log4net.Core.LevelEvaluator,log4net">
<threshold value="WSLog" />
</evaluator>
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="WSLog" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<bufferSize value="1"/>
<appendToFile value="true"/>
<rollingStyle value="Size"/>
<datePattern value="yyyyMMdd"/>
<MaxSizeRollBackups value="7"/>
<StaticLogFileName value="true"/>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<maximumFileSize value="5MB"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern
value="%newline__________________________________________________________%newlineTime:%utcdate%newline%newline%message%newline"/>
</layout>
</appender>
This works just fine until I have a huge string that needs to be logged. For example, if the string is about 8000 chars, Log4Net simply avoids writing it. It doesn't even write it truncated.
Is there a way to get large string logged (fully or even truncated)?

Have you tried enabling log4net's internal debugging to see if log4net is throwing an error
I tried a test program and it has no problem logging something like
log.Debug("Begin".PadRight(16000, '*') + "End");

Related

Log4net error with XmlHierarchyConfigurator. Missing Filter Property

One of our WebApis stopped outputting logs recently. In the Trace file we were getting this message:
log4net:ERROR XmlHierarchyConfigurator: Cannot find Property [filter] to set object on [log4net.Repository.Hierarchy.Hierarchy]
The config file looks as below and I'm assuming the filter in the error is the same filter in the config so I'm not sure why it can't find it.
I upgraded to the latest version of log4net and that solved the issue for a few days and then we got the "Cannot find Property [filter]" error again. The config file hasn't changed at all over this period.
<configuration>
<configSections>
<section name="log4net"
type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
</configSections>
<log4net>
<root>
<level value="ALL" />
<appender-ref ref="RollingFileAppender"/>
</root>
<filter type="log4net.Filter.LevelMatchFilter">
<acceptOnMatch value="true" /> <!--change to false to exclude info logs -->
<levelToMatch value="INFO" />
</filter>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="Logs/Log.txt" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="1001KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level: %message%newline" />
</layout>
</appender>
</log4net>
</configuration>
It's weird that it worked for a while, stopped, updgraded, worked for a while, stopped. I'm at at loss as to what could have changed to make it stop working either time.
Thanks in advance for any help.
Your configuration is not valid.
A filter can only be defined within an appender.
The documentation mentions:
Filters elements may only be defined as children of <appender>
elements.
Move the filter definition to the appender as shown below.
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<acceptOnMatch value="true" /> <!--change to false to exclude info logs -->
<levelToMatch value="INFO" />
</filter>
<file value="Logs/Log.txt" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="1001KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level: %message%newline" />
</layout>
</appender>
(I can't explain why the error only occurs at certain/random times; probably it (re-)occurs at configuration time eg. after an website/appdomain recycle) ...
In the end, Log4net tries to keep continuing as much as possible.

Why is the date on the file not rolling?

I must be doing something stupid but I can't think of it (I believe the core of my problem is that the PatternString is not dynamic and it gets set once when the program starts). Here is my lognet.config file:
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="F:\Logs\MonitorService_%date{yyyyMMdd}.log" />
<appendToFile value="true" />
<rollingStyle value="Composite" />
<datePattern value="yyyyMMdd" />
<maxSizeRollBackups value="5" />
<maximumFileSize value="3000MB" />
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%d [%t] %-5p %c :: %m%n" />
</layout>
</appender>
It seems like the files are coming out in a screwed up manner as:
F:\Logs\MonitorService_20170212.log
F:\Logs\MonitorService_20170212.log20170613
F:\Logs\MonitorService_20170212.log20170614
I would like them to come out as follows when they roll from day to day:
F:\Logs\MonitorService_20170612.log
F:\Logs\MonitorService_20170613.log
F:\Logs\MonitorService_20170614.log
What am I doing wrong?
There's no need to put the date in the file element's value.
The datePattern element determines the suffix applied to a log file when a new log file is created.
<file type="log4net.Util.PatternString" value="F:\Logs\MonitorService" />
<datePattern value="_yyyyMMdd" />
Here, the current log file will be called 'MonitorService' and when it is rolled on, the file will be renamed 'MonitorService_20170622' and a new file called 'MonitorService' will be created to store new log messages.

log4net generated file has a wrong (null) name

I'm using log4net to log things. In my web application, the Web.config file contains the following section:
<appender name="FileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="\\PathWhereThingsAreLogged\%property{HostName}-NameOfTheApplication" />
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
<appendToFile value="true" />
<maximumFileSize value="10MB"/>
<maxSizeRollBackups value="5" />
<rollingStyle value="Size" />
<rollingMode value="Size" />
<datePattern value=".yyyy-MM-dd'.log'" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date (%file:%line) %-5level - %message%newline" />
</layout>
</appender>
Logs appear in the file, so that's cool, but sadly the name of the file is incorrect. Its name is "(null)-NameOfTheApplication" instead of using the %property{HostName} declared in the file declaration.
Any help would be appreciated, thanks!
Actually, properties must be declared beforehand!
In a web application, put that in your Global.asax.cs file, in the Application_Start() method:
GlobalContext.Properties["HostName"] = Environment.MachineName;
In a windows service or a job, put it in the Program.cs in the Main(string[] args) method.

Log4Net is creating the file in wrong folder

Following is the appender written in log4net's configuration file
<appender name="RollingFileAppenderForError" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="D:\WEB\LOGs\%date{yyyyMMdd}\"/>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<appendToFile value="true"/>
<rollingStyle value="Composite"/>
<datePattern value="lo\gs_yyyyMMdd.lo\g"/>
<maxSizeRollBackups value="50"/>
<maximumFileSize value="1MB"/>
<staticLogFileName value="false"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="[%date{yyyy-MM-dd HH:mm:ss, fff}] [%property{ServiceTxnID}] [%property{TxnRequestID}] %-5level %logger{2} %ndc - %newline Exception: %message - %exception %newline "/>
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="FATAL" />
</filter>
</appender>
Here the problem is, in local and QA environment log4net is writing the log file in correct folder (New folder created everyday) but in production environment its writing the log file in wrong folder let say
In the folder for day 20130706 (YYYYMMDD) its writing the files of logs_20130706.log and logs_20130707.log. and in folder 20130707 we can see the files logs_20130707.log and logs_20130708.log.
I could not get the problem exactly where we are doing a mistake. Will be great if anyone can help me in this.
I guess the file type attribute is not re-calculated as often as the datePattern, you can try this:
<appender name="RollingFileAppenderForError" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="D:\WEB\LOGs"/>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<appendToFile value="true"/>
<rollingStyle value="Composite"/>
<datePattern value="yyyyMMdd\\\\'logs_'yyyyMMdd'.log'"/>
....
</appender>

log4net one file per run

I need my application to create a log file each time it runs.
My preferred format would be App.log.yyyy-MM-dd_HH-mm-ss. If that's not possible, I'd settle for App.log.yyyy-MM-dd.counter
This is my current appender configuration:
<appender name="File" type="log4net.Appender.RollingFileAppender">
<file value="App.log"/>
<rollingStyle value="Date"/>
<datePattern value=".yyyy-MM-dd_HH-mm-ss"/>
<staticLogFileName value="false"/>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
</appender>
But it creates a random number of files based on the date and time.
I assume that the application should create only one log file every time it runs, so you do not need a rolling file appender (though my solution would apply for rolling file appenders as well):
<appender name="FileAppender" type="log4net.Appender.FileAppender">
<file type="log4net.Util.PatternString" value="c:\temp\App-%date{yyyy-MM-dd_HH-mm-ss}.log" />
<appendToFile value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%2thread] %-5level - %message%newline" />
</layout>
</appender>
(Obviously you can use other your own layout and other settings for the file appender.)
Also note that you can set your rolling style as
rollingstyle="Once"
and it will create a new file every time it is run. If staticLogFileName is set to true (e.g., logname.log) the previous logs will be set to logname.log.1, logname.log.2, etc.
The number of files kept before overwriting the oldest (say, 10) can be controlled by setting
maxSizeRollBackups="10"
Edit:
My config, which creates a datestamped log per execution (unless one exists, in which case it follows the .1 rule, looks like this:
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="Logs\MyLog-%date{dd-MM-yyyy}.log" />
<appendToFile value="false" />
<maxSizeRollBackups value="-1" /> <!--infinite-->
<staticLogFileName value="true" />
<rollingStyle value="Once" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5level %date [%thread] %c{1} - %m%n" />
</layout>
</appender>
Not 100% sure if I need appendToFile="false" as the docs say that's done automatically when you use rollingStyle="Once", but this makes it clearer in any case.
It's documented from apache in the log4net docs at:
https://logging.apache.org/log4net/release/config-examples.html
ctrl+f for "per program execution"
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="logfile.txt" />
<appendToFile value="false" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="-1" />
<maximumFileSize value="50GB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>

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