How to Email an Entire Log File through Nlog - vb.net

Question

Salvete! nLog for .NET has the capability to send log entries as email. But if we want to send the entire current log file, how can it be done, short of reading the log file into a string and passing that as an nLog {$message}? I don't see that nLog has a property in its mailtarget for attachments. How can this be done?

Answer 1

I just did this today in C#. I followed the answer provided by arkmuetz here How to get path of current target file using NLog in runtime? to first get the filename of the Nlog target. I then read the file and copied the contents of the file to another Nlog target which emailed the log in the body of the message.
First I created an NlogHelper Class
public static class NlogHelper
{
/// <summary>
/// Gets LogFileName by TargetName
/// </summary>
/// <param name="targetName">The nLog targetname for the specified logger.</param>
/// <returns></returns>
/// <remarks>https://stackoverflow.com/questions/11452645/how-to-get-path-of-current-target-file-using-nlog-in-runtime</remarks>
public static string GetLogFileName(string targetName)
{
string fileName = null;
if (LogManager.Configuration != null && LogManager.Configuration.ConfiguredNamedTargets.Count != 0)
{
Target target = LogManager.Configuration.FindTargetByName(targetName);
if (target == null)
{
throw new Exception("Could not find target named: " + targetName);
}
FileTarget fileTarget = null;
WrapperTargetBase wrapperTarget = target as WrapperTargetBase;
// Unwrap the target if necessary.
if (wrapperTarget == null)
{
fileTarget = target as FileTarget;
}
else
{
fileTarget = wrapperTarget.WrappedTarget as FileTarget;
}
if (fileTarget == null)
{
throw new Exception("Could not get a FileTarget from " + target.GetType());
}
var logEventInfo = new LogEventInfo { TimeStamp = DateTime.Now };
fileName = fileTarget.FileName.Render(logEventInfo);
}
else
{
throw new Exception("LogManager contains no Configuration or there are no named targets");
}
//if (!File.Exists(fileName))
//{
// throw new Exception("File " + fileName + " does not exist");
//}
return fileName;
}
}
Next I retrieved the file name in the constructor and stored it for later use.
_logLileName = NlogHelper.GetLogFileName("DailyFile");
For my purposes I created property that I later used to retrieve the contents of the log file.
public string LogFileContent
{
get
{
return File.ReadAllText(_logLileName);
}
}
Finally I added the contents of the file to the log to be emailed.
_logger.Error("Excel Builder LinkShare Error encountered -- Some companies did not complete succesfully!. Please review logs. \n" + mfb.LogFileContent);
Here is my nLog.config file thought will help make things more clear.
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<targets>
<target name="console" xsi:type="ColoredConsole"
layout="${date:format=HH\:mm\:ss}|${level}|${stacktrace}|${message}" />
<target name="file" xsi:type="File" fileName="${basedir}/DomoExcelBuilderLog.txt"
layout="${stacktrace} ${message}" />
<target name="DailyFile" xsi:type="File" fileName="C:\Temp\Log${shortdate}.txt"
layout="${date:format=HH\:mm\:ss} --> ${message}" deleteOldFileOnStartup="true" />
<target name="file2" xsi:type="File" fileName="${basedir}/ServiceLog.txt"
layout="${stacktrace} ${message}" />
<target name="MyMailer" xsi:type="Mail"
smtpServer="some.server.com"
smtpPort="587"
smtpAuthentication="Basic"
smtpUsername="no-reply"
smtpPassword="somepassword"
enableSsl="true"
from="no-reply#some.server.com"
to="myemail#gmail.com"/>
</targets>
<rules>
<logger name="MultipleFileBuilder" minlevel="Trace" writeTo="DailyFile" />
<logger name="ExcelBuilderService" minlevel="Debug" writeto="MyMailer" />
</rules>
</nlog>
My application first logs to the logger named 'MultipleFileBuilder'. I then use the NLogHelper class to retrieve the contents of the Target 'DailiyFile'.
Hope this helps someoneout.
(NOTE: I removed the checking to see if the file exists in the 'GetLogFileName' method because in my case file didn't exist.)

Answer 2

I think you may use a combination of targets: default target + MethodCall and then send email manually or use Mail + Buffering to send a batch of records.