NLog.xLogger

An extension of NLog.Logger that provides additional functionality for tracing the entry and exit, arbitrary checkpoints, exceptions and stack traces within methods.

This library depends on NLog, Json.NET and my own BigFont Class.

Installation

Install from the NuGet gallery GUI or with the Package Manager Console using the following command:

Install-Package NLog.xLogger

NLog.xLogger

The xLogger class is the only type within the namespace. This type extends NLog.Logger.

Instantiating

xLogger instances are instantiated using the LogManager.GetLogger() and LogManager.GetCurrentClassLogger() factory methods provided by NLog.

The GetCurrentClassLogger() method returns an instance of xLogger named using the current class name.

private xLogger logger = (xLogger)LogManager.GetCurrentClassLogger(typeof(xLogger));

Note that typeof(xLogger) must be passed to the factory method so that the correct type can be instantiated. The result of the method must also be cast to xLogger.

The GetLogger() method returns a named instance of xLogger using the supplied name.

private xLogger logger = (xLogger)LogManager.GetLogger("generic logger name", typeof(xLogger));

xLogManager

The xLogManager wrapper for LogManager may also be used to create instances of xLogger using the GetCurrentClassxLogger() and GetxLogger() methods.

private xLogger logger = xLogManager.GetxLogger("generic name");
private xLogger logger = xLogManager.GetCurrentClassxLogger();

Methods

EnterMethod()

The EnterMethod() method is used to log the entry point of a method. The method accepts an object array containing the method parameters and boolean used to determine whether to persist the timestamp of entry. Returns a Guid if persistence is used, default(Guid) otherwise.

The static method xLogger.Params() is included to assist with the building of the object array. Pass each method parameter, in order, to this method and an object array containing the passed arguments is returned. If you wish to exclude any arguments from logging, replace the passed argument with new xLogger.ExcludedParam(). This maintains proper positioning, which is important so that reflection can retrieve the name and type of the parameter.

Note that the class ExampleObject has been created to demonstrate the serialization functionality and will continue to be used for the remainder of the examples.

Example

public static void EnterMethodExample(int one, int two, ExampleObject three)
{
    logger.EnterMethod(xLogger.Params(one, two, three));

    // method body
    logger.Trace("Standard log message");
}

Output

[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ──► Entering method: Void EnterMethodExample<Tone, Ttwo>(Int32 one, Int32 two, ExampleObject three) (Program.cs:line 56)
[x]: │   ├┄┈ Tone: System.String
[x]: │   ├┄┈ Ttwo: System.Boolean
[x]: │   ├┄┈ one: 1
[x]: │   ├┄┈ two: 2
[x]: │   ├┄┈ three: {
[x]: │   ├┄┈ three:   "Num": 3,
[x]: │   ├┄┈ three:   "Str": "three",
[x]: │   ├┄┈ three:   "List": [
[x]: │   ├┄┈ three:     1.1,
[x]: │   ├┄┈ three:     2.2,
[x]: │   ├┄┈ three:     3.3
[x]: │   ├┄┈ three:   ]
[x]: │   └┄┈ three: }
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: Standard log message 

ExitMethod()

The ExitMethod() method logs the exit point of a method. The method accepts an object representing the method return value and an optional Guid, used if the corresponding EnterMethod() was called with the persistence option.

Example

public static ExampleObject ExitMethodPersistentExample(int one, int two)
{
    Guid persistedGuid = logger.EnterMethod(xLogger.Params(one, two), true);

    // method body

    logger.Trace("Standard log message");
    ExampleObject returnValue = new ExampleObject(1, "return", new double[] { 5.5 }.ToList());

    logger.ExitMethod(returnValue, persistedGuid);
    return returnValue;
}

Output

[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ──► Entering method: ExampleObject ExitMethodPersistentExample(Int32 one, Int32 two) (Program.cs:line 71), persisting with Guid: ee9f56c7-f910-447b-8d03-e14bd8598654
[x]: │   ├┄┈ one: 1
[x]: │   └┄┈ two: 2
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: Standard log message
[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ◄── Exiting method: ExampleObject ExitMethodPersistentExample(Int32 one, Int32 two) (Program.cs:line 78), Guid: ee9f56c7-f910-447b-8d03-e14bd8598654
[x]: │   ├┄┈ return: {
[x]: │   ├┄┈ return:   "Num": 1,
[x]: │   ├┄┈ return:   "Str": "return",
[x]: │   ├┄┈ return:   "List": [
[x]: │   ├┄┈ return:     5.5
[x]: │   ├┄┈ return:   ]
[x]: │   └┄┈ return: }
[x]: ├────────────────────────────────────┄┈
[x]: │ ◊ Method execution duration: 2.0017ms
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈

Checkpoint()

The Checkpoint() method logs an arbitrary checkpoint anywhere within the method body. The method accepts a string representing the name of the checkpoint, an object array containing an arbitrary list of variables, a string array containing the names of the variables contained in the object list, and an optional Guid, used if the corresponding EnterMethod() call used the persistence option.

Example

public static int CheckpointExample(int one)
{
    Guid persistedGuid = logger.EnterMethod(xLogger.Params(one), true);

    logger.Trace("Standard log message");
    int two = 2;
    int three = 3;

    logger.Checkpoint("example checkpoint", xLogger.Vars(one, two, three), xLogger.Names("one", "two", "three"), persistedGuid);

    logger.Trace("Another standard log message");

    int returnValue = one + two + three;

    logger.ExitMethod(returnValue, persistedGuid);
    return returnValue;
}

Output

[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ──► Entering method: Int32 CheckpointExample(Int32 one) (Program.cs:line 89), persisting with Guid: 9792bbef-4609-429d-a0d3-478ba65e9b0e
[x]: │   └┄┈ one: 1
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: Standard log message
[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ √ Checkpoint 'example checkpoint' reached in method: Int32 CheckpointExample(Int32 one) (Program.cs:line 95), Guid: 9792bbef-4609-429d-a0d3-478ba65e9b0e
[x]: │   ├┄┈ one: 1
[x]: │   ├┄┈ two: 2
[x]: │   └┄┈ three: 3
[x]: ├────────────────────────────────────┄┈
[x]: │ ◊ Current execution duration: 1.0009ms
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: Another standard log message
[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ◄── Exiting method: Int32 CheckpointExample(Int32 one) (Program.cs:line 101), Guid: 9792bbef-4609-429d-a0d3-478ba65e9b0e
[x]: │   └┄┈ return: 6
[x]: ├────────────────────────────────────┄┈
[x]: │ ◊ Method execution duration: 1.0009ms
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈

Exception()

The Exception() method logs exception details. The method differs from the others in that it can log to levels other than Trace. The first parameter is of type LogLevel which is an enumeration of the logging levels within NLog.
Other parameters are the Exception that was caught and, as always, the optional Guid created if the method was entered with the persistence option.

Example

public static void ExceptionExample()
{
	logger.EnterMethod();

	try
	{
		// intentionally raise an exception
		var arr = new string[5];
		Console.WriteLine(arr[5]);
	}
	catch (Exception ex)
	{
		logger.Exception(LogLevel.Error, ex);
	}
	finally
	{
		logger.ExitMethod();
	}
}

Output

[x]: ┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │ ──► Entering method: Void ExceptionExample() (Program.cs:line 110)
[x]: └──────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: ┌──┐┌────────────────────────────────────────────────────────────────────────────────────────────────────┄┈
[x]: │██││ ╳ Exception 'IndexOutOfRangeException' caught in method: Void ExceptionExample() (Program.cs:line 120)
[x]: │██││   └┄┈ "Index was outside the bounds of the array."
[x]: │██│├────────────────────────────────────┄┈
[x]: │██││   └┄► Void Main(String[] args)
[x]: │██││      └┄► Void ExceptionExample()
[x]: │██│├──────────