How To Implement NLog In WebAPI

In this article, I will cover the following.

Definition
Support
Log Level
Why we need a log
Where to log
Implementation
Summary

After reading this article, I hope you will be able to use the logging feature easily.

Definition

NLog is a flexible and free logging platform for various .NET platforms, including .NET standard. NLog makes it easy to write to several targets (database, file, event viewer).

NLog is an extraordinary open-source logging device that enables the designers to effortlessly and proficiently actualize custom logging. NLog can be arranged to log to various targets.

Support

NLog supports the following platforms,

.NET Framework 3.5, 4, 4.5, 4.6 & 4.7
.NET Framework 4 client profile
Xamarin Android
Xamarin iOS
Windows Phone 8
Silverlight 4 and 5
Mono 4
ASP.NET 4 (NLog.Web package)
ASP.NET Core (NLog.Web.AspNetCore package)
.NET Core (NLog.Extensions.Logging package)
.NET Standard 1.x - NLog 4.5
.NET Standard 2.x - NLog 4.5
UWP - NLog 4.5

Log levels

Each log passage has a dimension. What's more, every log is arranged to incorporate or overlook certain dimensions. A typical arrangement is to determine the base dimension where that dimension and larger amounts are incorporated. For instance, in the event that has the base dimension as Info, Info, Warn, Error, and Fatal are logged, however, Debug and Trace are disregarded.

The log levels, in sliding requests, are as per the following.

S.N	Level	Use
1	Fatal	Something terrible occurred; the application is going down
2	Error	Something fizzled; the application might possibly proceed
3	Warn	Something surprising; the application will proceed
4	Info	Normal conduct like mail sent, client refreshed profile, and so on.
5	Debug	For troubleshooting; the executed question, the client confirmed, session terminated
6	Trace	To follow troubleshooting; start technique X, end strategy X

Why we need a log

Logging is one of the key properties when creating any software application like on Windows and on the web etc. NLog is an incredible open-source logging instrument that enables software engineers to effectively and proficiently actualize the logging structure.

In this post, I will demonstrate the means expected to arrange and utilize NLog in our application.

Where to log

We can use NLog easily within the following places.

Files
Event Viewer Log
Database
Network
Email
Console

Implementation

Step 1

Open Visual Studio. Select File > New > Project.

Step 2

Select Web> ASP.NET Web Application > Give your project a name (I have given NLogTest), and then click OK.

Step 3

Select WebAPI and click OK.

Step 4

Now, you have to add NLog to your project.

So, follow the steps here. Right-click on your project solution, click on "Manage NugGet Packages". Click on the "Browse" link button and in the search box, type nlog. It will show you NLogDll as shown below. Just install this DLL.

After that, when you click "Install", you will get the following window, i.e., Preview Changes.

In this popup window, click the OK button. After it is successfully installed, you will get the Nlog DLL in your project reference.

Now, your half part of the configuration is done! Let us go to the next level.

Step 5

Now, add the following code to your config file.

<configSections>
<section name="nlog" type="NLog.Config.ConfigSectionHandler, NLog" />
</configSections>
<nlog xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<targets>
<target name="logfile" xsi:type="File" fileName="${basedir}/MyLogs/${date:format=yyyy-MM-dd}-api.log" />
<target name="eventlog" xsi:type="EventLog" layout="${message}" log="Application" source=" My Custom Api Services" />
<target name="database" type="Database" connectionString="Data Source=your sql source;initial catalog=YourDbNameDb;user id=u1;password=p1;MultipleActiveResultSets=True;">
<commandText> insert into ExceptionLog ([TimeStamp],[Level],Logger, [Message], UserId, Exception, StackTrace) values (@TimeStamp, @Level, @Logger, @Message, case when len(@UserID) = 0 then null else @UserId end, @Exception, @StackTrace); </commandText>
<parameter name="@TimeStamp" layout="${date}" />
<parameter name="@Level" layout="${level}" />
<parameter name="@Logger" layout="${logger}" />
<parameter name="@Message" layout="${message}" />
<parameter name="@UserId" layout="${mdc:user_id}" />
<parameter name="@Exception" layout="${exception}" />
<parameter name="@StackTrace" layout="${stacktrace}" />
<dbProvider>System.Data.SqlClient</dbProvider>
</target>
</targets>
<rules>
<logger name="*" minlevel="Debug" writeTo="database" />
<logger name="*" minlevel="Trace" writeTo="logfile" />
<logger name="*" minlevel="Trace" writeTo="eventlog" />
</rules>
</nlog>

In this config file, I am targeting to log into three places.

database
txt file
Event Viewer,

Please refer to the below screen.

Step 6

Now, in step 5, we need to create our DB Script as shown below.

CREATE TABLE [dbo].[exceptionlog]
(
[id] [INT] IDENTITY(1, 1) NOT NULL,
[timestamp] [DATETIME] NOT NULL,
[level] [VARCHAR](100) NOT NULL,
[logger] [VARCHAR](1000) NOT NULL,
[message] [VARCHAR](3600) NOT NULL,
[userid] [INT] NULL,
[exception] [VARCHAR](3600) NULL,
[stacktrace] [VARCHAR](3600) NULL,
CONSTRAINT [PK_ExceptionLog] PRIMARY KEY CLUSTERED ( [id] ASC )WITH (
pad_index = OFF, statistics_norecompute = OFF, ignore_dup_key = OFF,
allow_row_locks = on, allow_page_locks = on) ON [PRIMARY]
)
ON [PRIMARY]

Step 7

Now, go to your home controller and add the namespace nLog just like this -

using NLog;

And, add the following code to this index method. The information will log into target files.

using NLog;
using System;
using System.Web.Mvc;
namespace NLogTest.Controllers {
public class HomeController: Controller {
private static Logger logger = LogManager.GetCurrentClassLogger();
public ActionResult Index() {
ViewBag.Title = "Home Page";
logger.Info("Hell You have visited the Index view" + Environment.NewLine + DateTime.Now);
return View();
}
public ActionResult About() {
ViewBag.Message = "Your app description page.";
logger.Info("hello now You have visited the About view" + Environment.NewLine + DateTime.Now);
return View();
}
}
}

Now, run the application.

And open your SQL. You will see the following logs inserted in your database.

You can see this in your Event Viewer.

You can see the following in your text file.

Now, you can open your Event Viewer in the following ways.

To access the Event Viewer

Right-click on the Start button and select Control Panel > System & Security and double-click Administrative Tools.
Double-click Event Viewer.
Select the type of logs that you wish to review (error, information, etc.).

Or

Press Windows+R to open the Run dialog, and type "eventvwr".

Summary

With the majority of Web APIs, connecting your custom logging system is simple and smooth. With that close by, you can oversee your following and investigating systems and can use on the ground-breaking highlights of your most loved logging structure - like I utilized nLog for this situation.

I hope you like this post, for any query please write in the comment section.

11 Comments

Join the conversation! Your thoughts help the community grow.

sai james3y ago
Hi Hamid, how are you able to insert the data in the database for all the fields??
bhuwan5y ago
Well explained.
mostafa fallah6y ago
It was very good sample. Can you set me how can i set database configs for Postgre ?
Amir Naved7y ago
Great Job Hamid Khan Keep Going man
Zain Asghar7y ago
How we can send userId to the database while logging?
VASUDEVA THIRUMALAR MUNAGALA7y ago
Thanks for sharing .
- Hamid Khan7y ago
  Thanks for reading...…….
Rushi Mehta8y ago
Nice Article
- Hamid Khan8y ago
  Thanks for reading.................
Jignesh Kumar8y ago
Nice Article. Thanks for sharing
- Hamid Khan8y ago
  Thanks for reading................