When setting up a file target with a CSV layout, the CSV header is written to the file at the moment the first log message is sent by the application since it has started.
Whether the file is empty or not, the CSV header is always rewritten after restarting the application.
Steps to reproduce:
=============
1) Create a console application that logs a single message with configuration file as below:
<configuration>
<configSections>
<section name="nlog" type="NLog.Config.ConfigSectionHandler, NLog"/>
</configSections>
<nlog autoReload="true">
<targets>
<target
name="AllMessages"
type="File"
fileName="${basedir}/log/TestLog.csv"
archiveFileName="${basedir}/log/TestLog{##}.csv"
archiveAboveSize="20971520"
maxArchiveFiles="10"
archiveNumbering="Rolling">
<layout type="CSVLayout">
<column name="Time" layout="${longdate}" />
<column name="Level" layout="${level}"/>
<column name="Logger" layout="${logger}"/>
<column name="Message" layout="${message}" />
</layout>
</target>
</targets>
<rules>
<logger name="*" minlevel="Trace" writeTo="AllMessages" />
</rules>
</nlog>
</configuration>
2) Run the application twice.
Proposed fix:
=========
I found a way to fix the problem by making a small change to the 2FileTarget.cs" file. It checks whether the file is empty before writing the header.
I replaced the following code at line 1082:
if (writeHeader && !justData)
{
byte[] headerBytes = this.GetHeaderBytes();
if (headerBytes != null)
{
appenderToWrite.Write(headerBytes);
}
}
By the following code:
if (writeHeader && !justData)
{
long fileLength = 0;
DateTime lastWriteTime;
// Only write header on empty files or if file info cannot be obtained
if (!appenderToWrite.GetFileInfo(out lastWriteTime, out fileLength) || fileLength == 0)
{
byte[] headerBytes = this.GetHeaderBytes();
if (headerBytes != null)
{
appenderToWrite.Write(headerBytes);
}
}
}
Comments: ** Comment from web user: GreenHex **
Whether the file is empty or not, the CSV header is always rewritten after restarting the application.
Steps to reproduce:
=============
1) Create a console application that logs a single message with configuration file as below:
<configuration>
<configSections>
<section name="nlog" type="NLog.Config.ConfigSectionHandler, NLog"/>
</configSections>
<nlog autoReload="true">
<targets>
<target
name="AllMessages"
type="File"
fileName="${basedir}/log/TestLog.csv"
archiveFileName="${basedir}/log/TestLog{##}.csv"
archiveAboveSize="20971520"
maxArchiveFiles="10"
archiveNumbering="Rolling">
<layout type="CSVLayout">
<column name="Time" layout="${longdate}" />
<column name="Level" layout="${level}"/>
<column name="Logger" layout="${logger}"/>
<column name="Message" layout="${message}" />
</layout>
</target>
</targets>
<rules>
<logger name="*" minlevel="Trace" writeTo="AllMessages" />
</rules>
</nlog>
</configuration>
2) Run the application twice.
Proposed fix:
=========
I found a way to fix the problem by making a small change to the 2FileTarget.cs" file. It checks whether the file is empty before writing the header.
I replaced the following code at line 1082:
if (writeHeader && !justData)
{
byte[] headerBytes = this.GetHeaderBytes();
if (headerBytes != null)
{
appenderToWrite.Write(headerBytes);
}
}
By the following code:
if (writeHeader && !justData)
{
long fileLength = 0;
DateTime lastWriteTime;
// Only write header on empty files or if file info cannot be obtained
if (!appenderToWrite.GetFileInfo(out lastWriteTime, out fileLength) || fileLength == 0)
{
byte[] headerBytes = this.GetHeaderBytes();
if (headerBytes != null)
{
appenderToWrite.Write(headerBytes);
}
}
}
Comments: ** Comment from web user: GreenHex **
Where is the newest build? When I go to downloads the __latest nightly build is Jan 24, 2012, Alpha__
liam83 __wrote Sep 21, 2012 at 9:37 AM__
Has been fixed in the Github repository