I've got this settings for log4net in the log4net.config to allow multiple threads to write to the same file:
<appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender">
<!-- Minimal locking to allow multiple threads to write to the same file -->
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<file value="log\UI.log"/>
<appendToFile value="true"/>
<rollingStyle value="Date"/>
<maxSizeRollBackups value="30"/>
<datePattern value="-yyyyMMdd"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%newline%date [%thread] %-5level [%property{identity}] %logger{3} - %message%newline"/>
</layout>
</appender>
But after midnight the new created log file is being overwritten all the time and thus there is only the last one event in the file. After server restart it all goes right again till the next midnight.
So can anyone say whether this is a config issue or this is just a log4net issue?
The problem was solved by removing the locking model key since I have only one process (IIS, w3wp.exe) which uses the same logger.
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
Since it was said here:
If you use RollingFileAppender things become even worse as several process may try to start rolling the log file concurrently. RollingFileAppender completely ignores the locking model when rolling files, rolling files is simply not compatible with this scenario.
I think you will get unpredictable results.
My guess is that your use of a - sign on the datePattern is confusing the framework so that after the first roll any log triggers a roll event.
What happens when you try this with
<datePattern value="yyyyMMdd" />
per the example here.
To change the rolling period adjust the DatePattern value. For
example, a date pattern of "yyyyMMdd" will roll every day. See
System.Globalization.DateTimeFormatInfo for a list of available
patterns.
Related
Does log4net support circular logging? (I think that's the right term.)
I want to maintain the last N entries in a log file. Say N=100. If I have 100 entries and then add a 101st, the desired behavior would be to delete the 1st entry from the top of the file and add the new log entry at the bottom, so that there is always 100 (or fewer) entries, with the oldest entry at the top and the newest at the bottom.
Basically, I want to record a couple of pieces of information to a file every minute. I only am interesting in seeing/keeping the last 100 entries. I could roll my own solution, but I'm already using log4net for logging other issues and was hoping I could use it for this purpose, as well.
Thanks
Out of the box solution would be RollingFileAppender with Size limit. You cannot specify how many entries you want to keep in the file, but if you play with the size (lets say 100KB), you can get what you want.
Here is an example:
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="log.txt" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="0" />
<maximumFileSize value="100KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
</appender>
And some documentation about why setting maxSizeRollBackups is important in this case:
If set to zero, then there will be no backup files and the log file
will be truncated when it reaches MaxFileSize.
MaxSizeRollBackups RollingMode
I am trying to use log4net to log to a file with a variable name using log4net.Util.PatternString.
The appender configuration looks like this:
<appender name="file2" type="log4net.Appender.FileAppender">
<file type="log4net.Util.PatternString" value="c:\temp\MyLogFile_PID%processid.log" />
<appendToFile value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %level - %message%newline" />
</layout>
</appender>
With this configuration, the file is succesfully created with a name something like this:
MyLogFile_PID12345.log
I have succesfully used %processid, %random{8}, %env{SOME_ENV_VAR}, %property{MYPROPERTY} and %appsetting{someKey}.
But what I want is to insert a date, and no matter what I try, it seems that I cannot make it understand any of:
%date, %utcdate, %date{DATE}, %utcdate{DATE}, %date{ISO8601}, %date{ABSOLUTE}, %date{{HH:mm:ss}
or basically any form of date.
For example, what is wrong in:
<file type="log4net.Util.PatternString" value="c:\temp\MyLogFile_%date{ISO8601}.log" />
I have also tried to use a separate node for the conversion pattern configuration to no avail:
<file type="log4net.Util.PatternString">
<conversionPattern value="c:\temp\MyLogFile_%date{ISO8601}.log" />
</file>
Right now I am using a custom property (with %property{MY_CUSTOM_PROPERTY_WITH_THE_NAME_I_WANT}) to achieve a similar effect, but apart from being somewhat overkill, I wonder what I am doing wrong. I have tried in different computers and different applications and I cannot get what I intend.
By the way, my real aim is to use it in RollingFileAppender, but I am asking (and trying) here about FileAppender just for simplicity sake.
Any help?
I see you're using the type log4net.Util.PatternString directly instead of the appender log4net.Appender.FileAppender, any specific reason for that?
I'm just looking at the examples from https://logging.apache.org/log4net/release/config-examples.html
I finally got it!
It seems the only way it works is specifying a date format string, and with NO ':' in it.
Despite the examples in https://logging.apache.org/log4net/release/sdk/index.html, where it uses %date{HH:mm:ss,fff}, %date{dd MMM yyyy HH:mm:ss,fff}, %date{ISO8601}, %date{ABSOLUTE} none of them seem to work!
But this (and similar ones) finally do:
<file type="log4net.Util.PatternString" value="c:\temp\MyLogFile_%date{yyyy-MM-dd_HH-mm-ss}.log" />
I am still scratching my head if I was doing something wrong or the documentation is just plain confusing.
I think it has to do with the fact that the character ':' is allowed in Linux filenames, but not on Windows (I am using Windows, as 90+% of log4net users, I guess). And ISO8601 and ABSOLUTE don´t work either probably because in both cases log4net translates them to a string with ':' in it, failing for the same reasons.
If this is true, being a logger for .NET, a framework that is overwhelmingly used in Windows systems, I think this is something they should have in mind.
Problem solved (albeit with some doubts).
I'm working on a wpf application that uses log4net. It currently logs to a single file and only rolls over when it grows too large. I am trying to modify this so that it grows over when the file grows too large, when the date changes, or when the application is relaunched.
I am trying to get output as close to the following as possible
App_2017-07-06.0.txt //First launch on 2017-07-06
App_2017-07-06.1.txt //Rollover due to size limit
App_2017-07-06.2.txt //Application relaunch
App_2017-07-06.3.txt //Rollover due to size limit
App_2017-07-07.0.txt //Rollover due to date change
App_2017-07-07.1.txt //Rollover due to size limit
App_2017-07-07.2.txt //Application relaunch - Currently Logging File
From what I understand from the documentation, The rolling style can be set to "compostite" to capture date and size or it can be set to "once" to capture application relaunches. It doesn't seem to have a way to do all 3: http://logging.apache.org/log4net/release/sdk/html/T_log4net_Appender_RollingFileAppender_RollingMode.htm
I got it to the point where everything looks correct and works except the application relaunch overwrites a pre existing file (I imagine because of the appendToFile property). I just cant seem to get it working the way I need to and I can't find any answers in the documentation.
This question seems to be trying to achieve a similar goal, but did not solve my problem:
How do I force a rollover at application startup with Log4net RolloverFileAppender?
Am I missing something? Is it just not possible to do this with log4net?
My current configuration
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="Log\App.txt" />
<appendToFile value="false" />
<rollingStyle value="Composite" />
<maximumFileSize value="10KB" />
<maxSizeRollBackups value="-1" />
<staticLogFileName value="false" />
<preserveLogFileNameExtension value="true" />
<countDirection value="1" />
<lockingModel type="log4net.Appender.RollingFileAppender+MinimalLock" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date %level User = %username Class = %property{ClassName} Method = %property{MethodName}%newlineMessage - %message%newline%exception%newline***************************************" />
</layout>
</appender>
My current output
App_2017-07-06.0.txt //First launch on 2017-07-06
App_2017-07-06.1.txt //Rollover due to size limit
App_2017-07-06.1.txt //Application relaunch - overwrites pre-existing file
App_2017-07-06.2.txt //Rollover due to size limit
App_2017-07-07.0.txt //Rollover due to date change
App_2017-07-07.1.txt //Rollover due to size limit
App_2017-07-07.1.txt //Application relaunch - overwrites pre-existing file - Currently logging file
As far as I know log4net copies the log file to xxxx.{number}.txt when it rolls over to the next file. So your first App_2017-07-06.1.txt was never created and is still called App_2017-07-06.txt when the application restarts. You have configured so App_2017-07-06.txt will be overridden and your first App_2017-07-06.1.txt was never created.
You can configure <appendToFile value="true" /> to not override the existing file.
I have a WCF service running on a single server, using Log4net to track usage via INFO and WARN level log entries. Using a RollingFileAppender with the following very standard config:
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="\\mylocation\data\PRD\myApp\MyService"/>
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="-yyyy-MM-dd'.log'" />
<staticLogFileName value="false" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
</appender>
<root>
<level value="ALL" />
<appender-ref ref="RollingLogFileAppender" />
<appender-ref ref="ADONetAppender_SqlServer" />
</root>
I also use an ADONetAppender, which receives redirected "WARN" level data and writes it to a DB table in SQL server via a stored procedure. The config for this is a bit long, so I have omitted it for readability.
I have this setup in our Dev and TST environments where it has been running fine. In the PRD environment, it seems to generate duplicate log files. The first is named according to my specified pattern i.e. "logfile-yyyy-mm-dd.log". The second file looks like an addition to the first, with the date pattern duplicated i.e. "logfile-yyyy-mm-dd.log.-yyyy-mm-dd.log".
Making this more interesting is that entries contained in the two files overlap by time. File 1 might have entries from 8am to 12am, and file 2 will also contain entries from the same time period. The entries are not duplicates, they are generated by different users of the service. The copies of Files 1 and 2 can be pretty much any size, so this is not an issue of reaching a size or date/time threshold and generating the next required log file.
The DB table entries contain all the expected rows, some contained in each of the log files. These rows are generated only by WARN level logging, and some WARNings appear in each log file.
I have bounced this off some log4net savvy folks in our shop, but nobody has a good idea of what might be causing this duplicate file behavior. Any ideas from Stackland appreciated.
Your date pattern shouldn't have .log after it. I also am unsure why you have two appenders declared in the root. You should be able to get rid of the root altogether, given the rest of your config it has no purpose (assuming you don't have more that isn't in the example).
I've found that this happens when the file being logged to is locked by another thread or process.
I'm assuming Log4Net creates the other file because it can't log to the configured logfile and thus creates a new file and logs to it, but I'd have to go through the log4net code to be sure of that assumption.
Try adding
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
to the appender element to minimize the amount of locking. Just be aware that there is additional overhead associated with using MinimalLock: http://logging.apache.org/log4net/release/sdk/log4net.Appender.FileAppender.MinimalLock.html
I had the same exact problem.
I confirm that was a permission issue. In my case the logfiles were generated by two different accounts (from a scheduled task and sometimes by a manual run via console), and in this case the file name had a duplicate date pattern.
After resetting the permissions to both users (the scheduled process user and the interactive users) the issue did not repeat anymore.
Greets,
Michele
According to the Log4Net documentation, the RollingFileAppender will only roll the log file when a message is logged. I need to log to this file, but import it every day into another database. I cannot use a database appender because I need the files and I have to translate the data from the log file to the database (it isn't a direct copy). The problem is if there is no log activity after midnight, the log doesn't roll. The importer looks for the previous days file (and I can't change this code), so if there is no activity and the log hasn't rolled, the importer doesn't find the file. Is there anyway to force the log to roll at midnight without having another thread that wakes up and forces it to roll? Could a custom appender do this? I would like to avoid this if possible.
Write a Windows Service that fires an event just after midnight that writes a dummy log entry using the same configuration.
You have to think about this from the point of the question "what code paths lead to the rollover routine?". Once you know how that routine is reached you can decide how to trigger it.
Could a custom appender do it? Sure, but no code in the appender will run until you log via it so you're back to square one.
As for the question "Is there anyway to force the log to roll at midnight without having another thread that wakes up and forces it to roll?", I would say that that question is equivalent to "Is it possible to force the log to roll at midnight without any code being run?". I'm not trying to be funny about it, or to insult you, I'm just trying to restate the question in a way which will hopefully answer it for you. :-)
The easiest way to solve this is to have something wake up and log to force the file to rotate.
According to the RollingFileAppender documentation you can set it to roll on a daily basis, see this configuration:
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="logfile" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="yyyyMMdd" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>