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Azure Functions : NLog and Database

Prashant Pratap's avatar
Apr 01, 2019
First published on MSDN on Mar 16, 2017

Here are steps to write NLog to Database in Azure Functions

1. via Config (NLog.config)

<?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="logfile" xsi:type="File" fileName="file.txt" />-->

<target name="logfile" xsi:type="Database" connectionstring="Server=dbservername.database.windows.net,1433;Initial Catalog=dbname;Persist Security Info=False;User ID=dbuser;Password=password; MultipleActiveResultSets=False; Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;">

<commandText>

insert into LogTable(time_stamp,level,logger,message) values(@time_stamp, @level, @logger, @message);

</commandText>

<parameter name="@time_stamp" layout="${date}" />

<parameter name="@level" layout="${level}" />

<parameter name="@logger" layout="${logger}" />

<parameter name="@message" layout="${message}" />

</target>

</targets>

<rules>

<logger name="*" minlevel="Trace" writeTo="logfile" />

</rules>

</nlog>

2. via Code

static void Main(string[] args)

{

LogManager.ThrowExceptions = true;

LogManager.ThrowConfigExceptions = true;

//InternalLogger.LogToConsole = true;

InternalLogger.LogFile = "log.txt";

InternalLogger.LogLevel = LogLevel.Trace;

#if DEBUG1 //FILE_TARGET

NLog.Targets.FileTarget target = new NLog.Targets.FileTarget("file_target");

target.FileName = "logfile.txt";

NLog.Config.SimpleConfigurator.ConfigureForTargetLogging(target, LogLevel.Trace);

Logger logger = LogManager.GetLogger("file_target");

#elif DEBUG2

NLog.Targets.DatabaseTarget target = new NLog.Targets.DatabaseTarget("db_target");

NLog.Targets.DatabaseParameterInfo param;

//target.DBProvider = "System.Data.SqlClient";

target.DBHost = "dbservername.database.windows.net";

target.DBUserName = "dbuser";

target.DBPassword = "password";

target.DBDatabase = "dbname";

target.CommandText = "insert into LogTable(time_stamp,level,logger,message) values(@time_stamp, @level, @logger, @message);";

param = new NLog.Targets.DatabaseParameterInfo();

param.Name = "@time_stamp";

param.Layout = "${date}";

target.Parameters.Add(param);

param = new NLog.Targets.DatabaseParameterInfo();

param.Name = "@level";

param.Layout = "${level}";

target.Parameters.Add(param);

param = new NLog.Targets.DatabaseParameterInfo();

param.Name = "@logger";

param.Layout = "${logger}";

target.Parameters.Add(param);

param = new NLog.Targets.DatabaseParameterInfo();

param.Name = "@message";

param.Layout = "${message}";

target.Parameters.Add(param);

NLog.Config.SimpleConfigurator.ConfigureForTargetLogging(target, LogLevel.Trace);

Logger logger = LogManager.GetLogger("db_target");

#else

Logger logger = LogManager.GetCurrentClassLogger();

#endif

logger.Trace("Sample trace message");

logger.Debug("Sample debug message");

logger.Info("Sample informational message");

logger.Warn("Sample warning message");

logger.Error("Sample error message");

logger.Fatal("Sample fatal error message");

LogManager.Flush();

}

3. In Azure Functions, we need to set the location of NLog.config file using XmlLoggingConfiguration() class as shown below:

using System;

using NLog;

using NLog.Common;

using NLog.Config;

private static Logger logger = null;

public static void Run(TimerInfo myTimer, TraceWriter log)

{

log.Info($"C# Timer trigger function executed at: {DateTime.Now}");

if (logger == null)

{

LogManager.ThrowExceptions = true;

LogManager.ThrowConfigExceptions = true;

//InternalLogger.LogToConsole = true;

InternalLogger.LogFile = "log.txt";

InternalLogger.LogLevel = LogLevel.Trace;

LogManager.Configuration = new XmlLoggingConfiguration("D:\\home\\site\\wwwroot\\<your function name>\\NLog.config");

logger = LogManager.GetCurrentClassLogger();

}

4. Also note, we need to add NuGet package details in the Project.json as shown below

Updated Aug 24, 2020
Version 2.0
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