log4net one file per run - log4net

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>

Related

log4net - specify which file to create. Do not create all appenders

I have a project in my solution that runs several different background jobs using Hangfire. I would like to be able to specify a different log file to be created using Log4Net based on the background job that is running.
For example;
job 1 does validation checks across a database and job 2 synchronizes data from a 3rd party app into another database
I have several appenders specified in the config file but all log files get created when I run job 1 or job 2. I want a log file only to be created per job e.g. when I run Job 1 log file job1.xml gets created and not job2.xml and vice versa
Is there any way of specifying the appender only? In the below example I want the file c:\logging\testing\jobs3-%date{ddMMMyyyy-hhmmss}.xml to be created only not the others
XmlConfigurator.Configure();
log4net.ILog log = log4net.LogManager.GetLogger("xmlFile2");
=====config file========
<appender name="file" type="log4net.Appender.RollingFileAppender">
<file value="c:\logging\job1.log" />
<appendToFile value="true" />
<rollingStyle value="Once" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date - [%M] %level %logger - %message%newline" />
</layout>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
</appender>
<appender name="xmlFile" type="log4net.Appender.FileAppender">
<file type="log4net.Util.PatternString" value="c:\logging\testing\job2-%date{ddMMMyyyy-hhmmss}.xml" />
<appendToFile value="true" />
<layout type="log4net.Layout.XmlLayoutSchemaLog4j">
<locationInfo value="true" />
</layout>
<param name="Encoding" value="utf-8" />
</appender>
<appender name="xmlFile2" type="log4net.Appender.FileAppender">
<file type="log4net.Util.PatternString" value="c:\logging\testing\jobs3-%date{ddMMMyyyy-hhmmss}.xml" />
<appendToFile value="true" />
<layout type="log4net.Layout.XmlLayoutSchemaLog4j">
<locationInfo value="true" />
</layout>
<param name="Encoding" value="utf-8" />
</appender>
</log4net>

Is there a way to have log4net create log file only when there is logging activity?

We changed our log4net file name to include the current date but only want log files created on those dates that there is logged activity. This is our current configuration:
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="{0}\\logfiles\\log%date{{yyyyMMdd}}-${{COMPUTERNAME}}.log" />
<appendToFile value="true" />
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10MB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date %-5level %logger %message%newline" />
</layout>
</appender>
<root>
<level value="WARN" />
<appender-ref ref="RollingFileAppender" />
</root>
</log4net>
It's producing empty files on days when the logger is created but no messages of WARN or greater are written. Is there a configuration to prevent empty files?

How to append rolling index BEFORE file extension in log filename

I am using the RollingLogFileAppender and it works great and it's rolling over into new files. But it's adding the .1, .2, etc at the very end of the file. So I end up with .log.1, .log.2, etc. So every file technically has a new extension that explorer doesn't know, so I can't just double click on a file to open.
How can I get the rolling file appender to insert that index BEFORE the file extension?
What I want is
.1.log
.2.log
Bonus would be for the current file to always be .0.log, that way they always sort correctly in explorer.
EDIT: added my current config settings
<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<file value="App_Data\\Logs\\" />
<datePattern value="dd.MM.yyyy'.log'" />
<staticLogFileName value="false" />
<appendToFile value="true" />
<rollingStyle value="Composite" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="5MB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
<logger name="File">
<level value="All" />
<appender-ref ref="RollingLogFileAppender" />
</logger>
</log4net>
You just need to use the PreserveLogFileNameExtension property on the RollingFileAppender.
See the following questions:
Log4net appender filename issue
Log4net RollingFileAppender Size rollingStyle file extension

Configuring Appenders

I have the following situation.
There are 2 classes: ClassA, ClassB. I want them to log in different files ClassA.log, ClassB.log. For this purpose I am using the RollingFileAppender. How can I write this in a shorter way than the following:
<appender name="RollingFileAppenderA" type="log4net.Appender.RollingFileAppender">
<file value="ClassA.log" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="100KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
<appender name="RollingFileAppenderB" type="log4net.Appender.RollingFileAppender">
<file value="ClassB.log" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="100KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
As you can see, the only thing the appenders differ is the filename where they are writing logs. So, is there a way to define a single RollingFileAppender for the given problem?
I have worked on several projects with multiple file appenders configured just like yours. To my knowledge there is no way to define a common appender configuration and then share that among multiple appenders. It probably has something to do with how log4net interprets the XML tags into Properties on the appenders. (And I have looked closely at the ForwardingAppender, but it's not built for that).
Is there any reason other than "don't repeat yourself" (DRY) that you want to clean up the configuration? If your app.config (or web.config) is getting out of hand, you can use a separate configuration file.

Log4Net: Rolling File appender, define extension

I want my logfile to look something like this:
2009-02-13.log
but the problem is that I can't seem to find any way to add the .log extension.
I've tried a lot of things but nothing helps.
This is what I have this far:
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="Logs/Log4Net/.log"/>
<appendToFile value="true"/>
<rollingStyle value="Date"/>
<datePattern value="yyyy-MM-dd" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline"/>
</layout>
</appender>
The other answers escape the "g" in "log" since "g" is a special character in datePattern. This isn't wrong, but I prefer to wrap the entire set of non-date characters in single quotes, like so:
<datePattern value="yyyy-MM-dd'.log'" />
This gives the same results, but is easier for me to manage. This way, I don't have to recall which specific characters are special for datePattern (the list is long and varied). If I forget one character then I don't run the risk of borking my file names; they're all nicely escaped en masse.
Try adding the .log extension to your date pattern like so and remove it from the file attribute.
<datePattern value="yyyy-MM-dd.lo\g"/>
...
<staticLogFileName value="false" />
log4net now also provides a PreserveLogFileNameExtension property that can force your .log extension to the end of the compound file name (including date pattern and/or size sequence number):
<file value="LogFiles/.log"/>
<preserveLogFileNameExtension value="true" />
<datePattern value="yyyy-MM-dd" />
add ".lo\g" to the end of your datepattern
This is my log file xml config.
The path to the log file is in the "file" tag
This will create a log file "2012-11-22.log" under the folder "LogFiles" in the route folder of my website.
NOTE: Make sure that the folder exists first!
<?xml version="1.0"?>
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
</configSections>
<log4net>
<root>
<level value="INFO"/>
<appender-ref ref="RollingFileAppender"/>
</root>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="LogFiles/"/>
<appendToFile value="true"/>
<rollingStyle value="Date"/>
<maxSizeRollBackups value="5"/>
<maximumFileSize value="10MB"/>
<datePattern value="yyyy-MM-dd'.log'" />
<staticLogFileName value="false"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %level %logger - %message%newline%exception"/>
</layout>
</appender>
</log4net>
</configuration>

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