\u00c7o\u011fu zaman geli\u015ftirmekte oldu\u011fumuz uygulamalarda, arkaplanda neyin olup bitti\u011fini anlayabilmek i\u00e7in genelde \u00e7e\u015fitli log’lama i\u015flemlerini ger\u00e7ekle\u015ftiririz. \u00d6zellikle b\u00fcy\u00fcmekte ve\u00a0b\u00fcy\u00fck \u00e7apta olan projelerde, monolithic\u00a0architecture’lar\u0131n yerine\u00a0distributed architecture’lar\u0131n tercih edilmesiyle beraber, distributed d\u00fcnya sa\u011flam\u0131\u015f oldu\u011fu bir \u00e7ok faydan\u0131n yan\u0131nda\u00a0business process y\u00f6netimi ve consistency gibi baz\u0131 sorunlar\u0131 da beraberinde\u00a0getirmektedir.<\/p>\n Yukar\u0131da ki gibi\u00a0bir \u00f6rnekle a\u00e7\u0131klamak gerekirse e\u011fer:<\/p>\n \u00d6rne\u011fin X request’i ilgili business i\u015flemini ger\u00e7ekle\u015ftirebilmesi i\u00e7in, -n tane service ile \u00e7al\u0131\u015fmas\u0131 gerekmektedir. Ger\u00e7ekle\u015ftirecek oldu\u011fu bu service call’lar sonucunda ise, olu\u015fturaca\u011f\u0131 bir result bulunmaktad\u0131r.<\/p>\n Peki, bu service call’lar\u0131 s\u0131ras\u0131nda herhangi bir noktada kopma\/network split ya\u015fan\u0131rsa? Hangi log i\u015flemi, hangi request i\u00e7erisinde ger\u00e7ekle\u015fti? \u0130\u015fte bu\u00a0gibi\u00a0problemlerde Correlation ID<\/strong>\u00a0yakla\u015f\u0131m\u0131 imdad\u0131m\u0131za ko\u015fmaktad\u0131r.<\/p>\n Service’ler aras\u0131nda her bir request i\u00e7in\u00a0unique identifier g\u00f6revini g\u00f6recek olan bir Correlation ID gezdirilir. Bu sayede hangi request hangi ko\u015fullarda ve nas\u0131l hata al\u0131nd\u0131\u011f\u0131n\u0131n log’lar\u0131n\u0131 takip edebilmek, olduk\u00e7a kolayla\u015facakt\u0131r.<\/p>\n Distributed yakla\u015f\u0131mlar\u0131n d\u0131\u015f\u0131nda baz\u0131 durumlarda ise\u00a0uygulamalar\u0131m\u0131zda ki\u00a0bottleneck’leri ortaya koyabilmek i\u00e7in farkl\u0131 senaryolarda test case’leri ve log i\u015flemleri ger\u00e7ekle\u015ftiririz.<\/p>\n \u00d6rne\u011fin X request’i, ilgili result set’i olu\u015fturabilmek i\u00e7in hangi business process’lerden\/gateway’lerden ge\u00e7iyor? Hangi parametreler ile ilerliyor? Nerede ne kadar vakit harc\u0131yor?<\/p>\n Bunlar gibi sorular\u0131 cevaplayabilmek i\u00e7in,\u00a0log’lama\u00a0i\u015flemini ger\u00e7ekle\u015ftirirken\u00a0Correlation ID\u00a0\u00e7\u00f6z\u00fcm\u00fc ile ilerleyebiliriz. Bu sayede istedi\u011fimiz contextual bilgileri log’larken, Correlation ID ile de\u00a0log’lamadaki\u00a0traceability’i artt\u0131rarak, bottleneck’leri h\u0131zl\u0131 bir \u015fekilde ortaya koyabiliriz.<\/p>\n Ger\u00e7ekle\u015ftirece\u011fimiz \u00f6rnekte log’lama i\u00e7in NLog<\/em> k\u00fct\u00fcphanesini kullanaca\u011f\u0131m. Loglama yaparken herhangi bir aspect k\u00fct\u00fcphanesi kullanmayaca\u011f\u0131m. Sizler dilerseniz lisansl\u0131 olarak PostSharp<\/em> veya open-source olarak\u00a0Fody<\/em> gibi k\u00fct\u00fcphaneler\u00a0arac\u0131l\u0131\u011f\u0131 ile intercept i\u015flemlerini ger\u00e7ekle\u015ftirerek log’lamalar\u0131 yapabilirsiniz.<\/p>\n “LogTraceWithCorrelationId<\/em>” isminde yeni bir console application olu\u015ftural\u0131m. \u0130\u00e7erisine a\u015fa\u011f\u0131daki resimde oldu\u011fu gibi NuGet<\/em>\u00a0\u00fczerinden “NLog<\/em>” ve “NLog.Config<\/em>” k\u00fct\u00fcphanelerini kural\u0131m.<\/p>\n K\u00fct\u00fcphanelerin kurulumu ard\u0131ndan \u00f6ncelikle “NLog.config<\/em>” dosyas\u0131n\u0131 a\u015fa\u011f\u0131daki gibi d\u00fczenleyelim.<\/p>\n Bu config dosyas\u0131 ile log’lar\u0131n\u00a0database’e kaydedilmesi gerekti\u011fini, parameter’lar ile de “commandText<\/em>” \u00fczerindeki parametreleri set ediyoruz. “rules<\/em>” k\u0131sm\u0131nda ise “minlevel<\/em>” parametresi ile “debug<\/em>” seviyesinde log’lanmas\u0131n\u0131 ve target olarak da “database<\/em>” target’\u0131n\u0131 kullanmas\u0131n\u0131 s\u00f6yl\u00fcyoruz.<\/p>\n NLog<\/em> ba\u015fl\u0131ca a\u015fa\u011f\u0131daki log level’lar\u0131n\u0131 desteklemektedir:<\/p>\n Bize \u00f6rne\u011fimizde debug level’\u0131 yeterli olacakt\u0131r.<\/p>\n Config dosyas\u0131n\u0131n ayarlanmas\u0131 ard\u0131ndan yukar\u0131daki parametrelere denk gelecek olan SQL<\/em> tablosunu da a\u015fa\u011f\u0131daki script ile olu\u015ftural\u0131m.<\/p>\n Tablo field’lar\u0131na\u00a0dikkat ettiyseniz “CorrelationId<\/em>” field’\u0131 d\u0131\u015f\u0131ndakiler, NLog<\/em>‘un sahip oldu\u011fu default field’lard\u0131r. Bu b\u00f6l\u00fcmde ise\u00a0“CorrelationId<\/em>” field’\u0131n\u0131 nas\u0131l kullanabilece\u011fimize\u00a0bakaca\u011f\u0131z.<\/p>\n NLog<\/em>‘un 4.1 versiyonundan sonra “${activityid}” parametresi ile, log mesajlar\u0131n\u0131 trace edebilmek i\u00e7in correlation id deste\u011fi getirilmi\u015ftir. Bundan \u00f6nceki versiyonlar\u0131nda ise bu tarz bir i\u015flemler i\u00e7in custom olarak bir layout renderer yazmak gerekiyordu.<\/p>\n Not<\/strong>: NLog<\/em>‘un ${activityid} parametresi correlation id’yi “System.Diagnostics<\/em>” namespace’i alt\u0131nda bulunan, “Trace.CorrelationManager.ActivityId<\/em>” property’sinden okumaktad\u0131r.<\/p><\/blockquote>\n Log k\u00fct\u00fcphanesi haz\u0131r oldu\u011funa g\u00f6re “Program.cs<\/em>” i a\u00e7al\u0131m ve a\u015fa\u011f\u0131daki gibi kodlayal\u0131m.<\/p>\n Dikkat edersek i\u00e7 i\u00e7e\u00a0sequentially olarak ilerleyen 2 adet method bulunmakta.<\/p>\n “Main<\/em>” method’u i\u00e7erisinde “System.Diagnostics.Trace.CorrelationManager.ActivityId<\/em>” property’sine yeni bir guid set ediyoruz. Ard\u0131ndan ilk method olan “DoWork<\/em>” method’unu call ediyoruz. Method’lar i\u00e7erisinde ise “LogManager.GetCurrentClassLogger<\/em>” method’u ile elde etmi\u015f oldu\u011fumuz NLog<\/em> instance’\u0131 \u00fczerinden, “Debug<\/em>” method’unu kullanarak bir log mesaj\u0131 at\u0131yoruz.<\/p>\n NLog<\/em> bu i\u015flemlerin ard\u0131ndan bu process bitene kadar set etmi\u015f oldu\u011fumuz\u00a0“ActivityId<\/em>” parametresini,\u00a0otomatik olarak log’lar aras\u0131nda ta\u015f\u0131yacakt\u0131r. Bu sayede herhangi bir process\/request i\u00e7in t\u00fcm ak\u0131\u015f\u0131 trace edebilmek kolay bir hale gelecektir.<\/p>\n Yukar\u0131daki console uygulamas\u0131n\u0131 \u00e7al\u0131\u015ft\u0131ral\u0131m ve \u00e7\u0131kt\u0131s\u0131na SQL Server Management Studio<\/em> \u00fczerinden bir bakal\u0131m.<\/p>\n![\"blog-arrows\"](\"\/wp-content\/uploads\/2016\/10\/blog-arrows.png\")
<\/a><\/p>\nSenaryo<\/h4>\n
<\/a><\/p>\nYakla\u015f\u0131m<\/h4>\n
<\/a><\/p>\n[Info:Entering] CorrelationID:12345 10\/16\/2016 10:05:45.125 FooNamespace.FooClass.FooMethod<T>, \"Parameter_1\", \"Parameter_2\"\r\n[Info:Executing] CorrelationID:12345 10\/16\/2016 10:05:58.95 FooNamespace.FooClass.FooMethod<T>, \"Parameter_1\", \"Parameter_2\"\r\n[Info:Leaving] CorrelationID:12345 10\/16\/2016 10:06:20.45 FooNamespace.FooClass.FooMethod<T>, \"Parameter_1\", \"Parameter_2\"<\/pre>\n
Loglama<\/h4>\n
<\/a><\/p>\n<nlog xmlns=\"http:\/\/www.nlog-project.org\/schemas\/NLog.xsd\"\r\n xmlns:xsi=\"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n throwExceptions=\"true\"\r\n internalLogLevel=\"Trace\"\r\n internalLogFile=\"..\\..\\..\\Logs\\nlog-app.log\">\r\n <targets>\r\n <!-- database -->\r\n <target name=\"database\" xsi:type=\"Database\" keepConnection=\"true\" useTransactions=\"true\"\r\n dbProvider=\"System.Data.SqlClient\"\r\n connectionString=\"data source=.;initial catalog=TestDb;integrated security=true;\"\r\n commandText=\"INSERT INTO Logs(EventDateTime, EventLevel, CorrelationId, MachineName, EventMessage, ErrorSource, ErrorClass, ErrorMethod, ErrorMessage, InnerErrorMessage) VALUES (@EventDateTime, @EventLevel, @CorrelationId, @MachineName, @EventMessage, @ErrorSource, @ErrorClass, @ErrorMethod, @ErrorMessage, @InnerErrorMessage)\">\r\n\r\n <!-- parameters for the command -->\r\n <parameter name=\"@EventDateTime\" layout=\"${date:s}\" \/>\r\n <parameter name=\"@EventLevel\" layout=\"${level}\" \/>\r\n <parameter name=\"@CorrelationId\" layout=\"${activityid}\"\/>\r\n <parameter name=\"@MachineName\" layout=\"${machinename}\" \/>\r\n <parameter name=\"@EventMessage\" layout=\"${message}\" \/>\r\n <parameter name=\"@ErrorSource\" layout=\"${event-context:item=error-source}\" \/>\r\n <parameter name=\"@ErrorClass\" layout=\"${event-context:item=error-class}\" \/>\r\n <parameter name=\"@ErrorMethod\" layout=\"${event-context:item=error-method}\" \/>\r\n <parameter name=\"@ErrorMessage\" layout=\"${event-context:item=error-message}\" \/>\r\n <parameter name=\"@InnerErrorMessage\" layout=\"${event-context:item=inner-error-message}\" \/>\r\n <\/target>\r\n <\/targets>\r\n <rules>\r\n <!-- logging rules here -->\r\n <logger name=\"*\" minlevel=\"Debug\" writeTo=\"database\" \/>\r\n <\/rules>\r\n<\/nlog><\/pre>\n\n
CREATE TABLE [dbo].[Logs](\r\n\t[Id] [int] IDENTITY(1,1) NOT NULL,\r\n\t[EventDateTime] [datetime] NOT NULL,\r\n\t[EventLevel] [nvarchar](100) NOT NULL,\r\n\t[CorrelationId] [uniqueidentifier] NOT NULL,\r\n\t[MachineName] [nvarchar](100) NOT NULL,\r\n\t[EventMessage] [nvarchar](max) NOT NULL,\r\n\t[ErrorSource] [nvarchar](100) NULL,\r\n\t[ErrorClass] [nvarchar](500) NULL,\r\n\t[ErrorMethod] [nvarchar](max) NULL,\r\n\t[ErrorMessage] [nvarchar](max) NULL,\r\n\t[InnerErrorMessage] [nvarchar](max) NULL,\r\n CONSTRAINT [PK_Logs] PRIMARY KEY CLUSTERED \r\n(\r\n\t[Id] ASC\r\n)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, \r\n ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]\r\n) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]<\/pre>\n
using System;\r\nusing NLog;\r\n\r\nnamespace LogTraceWithCorrelationId\r\n{\r\n class Program\r\n {\r\n private static Logger _logger = LogManager.GetCurrentClassLogger();\r\n\r\n static void Main(string[] args)\r\n {\r\n \/\/Per request\r\n System.Diagnostics.Trace.CorrelationManager.ActivityId = Guid.NewGuid();\r\n\r\n DoWork();\r\n }\r\n\r\n private static void DoWork()\r\n {\r\n \/\/...\r\n\r\n _logger.Debug(\"DoWork method'u \u00e7al\u0131\u015ft\u0131r\u0131ld\u0131.\");\r\n\r\n DoOtherWork();\r\n }\r\n\r\n private static void DoOtherWork()\r\n {\r\n \/\/...\r\n\r\n _logger.Debug(\"DoOtherWork method'u \u00e7al\u0131\u015ft\u0131r\u0131ld\u0131.\");\r\n }\r\n }\r\n}<\/pre>\n