NLog - Advanced .NET Logging

Using NLog with Mono

Jarek Kowalski — Mon, 31 Oct 2011 01:33:35 +0000

After releasing NLog 2.0 a number of people have reported problems with running on latest versions of Mono. Basically at the end of program execution (after the Main() has finished) the program locks up waiting for NLog logs to be flushed, so mono process never completes and needs to be killed.

This behavior is only specific to NLog 2.0 – NLog 1.0 did not exhibit this behavior. It seems to be related to threading and timers used by NLog 2.0 which are somehow not available in Mono when the program is about to be terminated. The same code works with .NET just fine. I haven’t fully investigated this issue – maybe Mono folks can see if this issue can be fixed in Mono itself?

Anyway – there is a simple way prevent the deadlock: just make sure you set LogManager.Configuration property to null before your application exits. This will cause Flush() to be executed before Main() finishes and will prevent …

NLog 2.0 has been released!

Jarek Kowalski — Mon, 18 Jul 2011 07:31:20 +0000

It is my great pleasure to announce that NLog 2.0 has been released.

NLog 2.0 release is focused on adding support for new platforms (Silverlight, .NET Framework 4, Windows Phone 7.x), improving logging architecture and manageability and addressing most frequently reported user issues.

Binaries can be downloaded from CodePlex.
Sources are available at GitHub.
NuGet packages are also available.

You can read the release notes at http://nlog-project.org/nlog-2-0-release-notes.…

NLog 2.0 Release Candidate is now available

Jarek Kowalski — Sat, 18 Jun 2011 07:17:41 +0000

It is our pleasure to announce that the Release Candidate (RC) of NLog 2.0 is now available for download. This is the last milestone before NLog 2.0 final release.

Binary downloads are available on CodePlex
Source code on GitHub
Full release notes can be found here.

Please download the release and report any problems you may find. Assuming no critical issues are found, NLog 2.0 will be released within a month from the RC release.…

Exception logging enhancements

Jarek Kowalski — Thu, 21 Apr 2011 05:12:00 +0000

One of the frequent feature requests I’ve been getting was to improve the way exceptions are logged. Recent builds of NLog 2.0 include several usability enhancements that should make working with exceptions much easier.

Conditional formatting

Conditional logging allows you to make your layouts somewhat more dynamic – you can include/exclude fields based on conditions, provide default values and so on. In order to achieve this, you have 3 new layout renderers at your disposal.

${onexception:INNER} - output

To render a layout when the exception is being logged, use ${onexception:INNER}, it will output INNER only when current log event includes an exception (in other words when it was emitted using any of the Logger.*Exception() methods. INNER can include other layouts, for example:

<targets>
  <target name="f" type="File" layout="${message}${onexception:EXCEPTION OCCURRED\:${exception:format=tostring}}" />
</targets>

It will output log message, but in case of exception, it will also log detailed exception information prefixed with "EXCEPTION OCCURRED:".…

Simplifying NLog.Extended.dll usage

Jarek Kowalski — Fri, 15 Apr 2011 06:44:38 +0000

I’d like to let you know about small simplification to using targets and layout renderers from NLog.Extended.dll. Previously you had to register them using configuration section:

<extensions>
  <add assembly="NLog.Extended" />
</extensions>

Starting with today’s Nightly build, this is no longer required – you can simply use extended items without extra registration (exactly like it worked in NLog 1.0). The only change is that you must have NLog.Extended.dll in the same directory as NLog.dll – you will get exception if it’s not present.

If you need NLog.Extended, please give this feature a try and report any issues you find.…

NLog for Windows Phone 7

Jarek Kowalski — Mon, 10 Jan 2011 05:06:43 +0000

This week I have checked in a port of NLog 2.0 for Windows Phone 7. It’s still very experimental and the intention of this release is to get feedback from people. Please use at your own risk.

Current build supports 8 targets:

Console – can be used to write logs to the console (only works in Emulator – see this post for instruction on how to enable console output)
Memory – stores traces in memory
MethodCall – runs user-provided method for each log message
Network, NLogViewer and Chainsaw – write XML-formatted log event over the network. Only HTTP:// and HTTPS:// protocols are supported.
WebService – sends log events to a web service using SOAP or POST
LogReceiverService – sends log events to LogReceiver web service using WCF

Note that File target and several others are not included because of current constraints of the platform APIs.

Here is a simple step-by-step tutorial for adding NLog to your WP7 app:

Download

NLog 2.0 Beta 1 has been released

Jarek Kowalski — Mon, 27 Sep 2010 01:59:48 +0000

It is my pleasure to announce that NLog 2.0 Beta 1 has been released.

NLog 2.0 release is focused on adding support for new platforms (Silverlight, .NET Framework 4), improving logging architecture and manageability and addressing most frequently reported user issues.

The following platforms are supported in this release:

.NET Framework 2.0 SP1 and above, 3.5 (Client and Extended profiles), 4.0 (Client and Extended profiles)
Silverlight 2.0, 3.0, 4.0
.NET Compact Framework 2.0, 3.5
Mono 2.x profile

Read full release notes:
http://nlog-project.org/nlog2-beta1-release-notes

Download Beta 1 bits on CodePlex:
http://nlog.codeplex.com/releases/view/52957

Source code is available on GitHub:
http://github.com/jkowalski/NLog/

Bugs can be reported on CodePlex:
http://nlog.codeplex.com/workitem/list/basic

Discuss on forum:
http://nlog-project.org/forum

Subscribe to NLog RSS feed:
http://nlog-project.org/feed

Follow @JarekKowalski on Twitter:
http://twitter.com/JarekKowalski…

Deploying NLog configuration files

Jarek Kowalski — Sat, 25 Sep 2010 20:10:56 +0000

Some of the targets supported by NLog require installation to be performed on the machine before the target can be used. For example, when logging to a database, a DBA needs to create the necessary tables, when logging to event log or performance counter, administrator of the machine must create them before the application can write to them.

NLog 2.0 comes with a new tool and APIs that lets you manage installation and uninstallation of objects which support logging.

Say you want to write logs to:

local SQLEXPRESS database

Event Log on the local machine

increase performance counter each time log message occurs.

With NLog 2.0, you can embed installation/uninstallations steps directly in the log configuration file, like in the following example:

<?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 xsi:type="Database" name="db">
      <!-- SQL command to be executed for each entry -->
      <…

New exception handling rules in NLog 2.0

Jarek Kowalski — Sun, 05 Sep 2010 17:32:36 +0000

NLog will introduce a change to logging exception handling and suppression. In NLog 1.0 all exceptions were disabled by default, but could be enabled by setting

<nlog throwExceptions=”true”>

</nlog>

or in code:

LogManager.ThrowExceptions = true;

This flag applied to configuration errors as well as runtime errors, which was problematic, because a simple configuration file typo could cause entire logging to be disabled silently.

To address this, NLog 2.0 will treat configuration errors separately from runtime errors. There will be two kinds of exceptions:

Configuration exceptions – raised during parsing of configuration file and wrapped in NLogConfigurationException. Such errors are fatal and will prevent your application from starting (this is the same as having malformed App.config or Web.config). The errors that cause this exception are:

syntax errors in NLog.config
invalid target names
invalid property names
invalid property values

Runtime exceptions (such as permission issues, connection failures, etc.) – raised during logging and

Routing System.Diagnostics.Trace and System.Diagnostics.TraceSource logs through NLog

Jarek Kowalski — Fri, 03 Sep 2010 04:15:43 +0000

I have recently added a trace listener class for NLog, which enables routing of System.Diagnostics.Trace and System.Diagnostics.TraceSource logs through your favorite log routing engine. This can be very useful for integrating components that don’t necessarily support logging through NLog as well as analyzing traces produced .NET Framework itself.

By using NLog trace listener you can send those logs via email, save them to a database, file or to any other supported log target.

Let’s create a simple example – application that makes network call. We will then enable network call tracing without touching a single line of code.

namespace TraceDemo
{
  using System.Net; 

  class Program
  {
    static void Main(string[] args)
    {
      var webClient = new WebClient();
      webClient.DownloadString("http://somehost/nosuchfile.txt");
    }
  }
}

As you can see the example is just using WebClient from System.Net namespace, and has no tracing-specific code. Internally WebClient is capable of outputting traces through System.Net trace source. To route those traces …