Logger Class

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When overridden in a derived form, provides functionality for loggers that handle events raised by the MSBuild engine.

MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.

Inheritance Hierarchy

System.Object
  Microsoft.Build.Utilities.Logger

Namespace:  Microsoft.Build.Utilities
Assembly:  Microsoft.Build.Utilities.Core (in Microsoft.Build.Utilities.Core.dll)

Syntax

'Declaration
Public MustInherit Class Logger _
    Implements ILogger

public abstract class Logger : ILogger

public ref class Logger abstract : ILogger

[<AbstractClass>]
type Logger =  
    class 
        interface ILogger 
    end

public abstract class Logger implements ILogger

The Logger type exposes the following members.

Constructors

  Name Description
Protected method Logger Initializes a new instance of the Logger class.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.

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Properties

  Name Description
Public property Parameters Gets or sets the user-defined parameters of the logger.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Public property Verbosity Gets or sets the level of detail to show in the event log.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.

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Methods

  Name Description
Public method Equals (Inherited from Object.)
Protected method Finalize (Inherited from Object.)
Public method FormatErrorEvent Generates an error message that is in the default format, from a BuildErrorEventArgs object.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Public method FormatWarningEvent Generates a warning message that is in the default format, from a BuildWarningEventArgs object.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Public method GetHashCode (Inherited from Object.)
Public method GetType (Inherited from Object.)
Public method Initialize When overridden in a derived class, subscribes the logger to specific events.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Public method IsVerbosityAtLeast Determines whether the current Verbosity setting is at least the value that is passed in.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Protected method MemberwiseClone (Inherited from Object.)
Public method Shutdown When overridden in a derived class, releases the resources allocated to the logger at the time of initialization or during the build.MSBuild is now included in Visual Studio instead of the .NET Framework. You can use MSBuild 12.0 side-by-side with versions previously deployed with the .NET Framework.For more information, see What's New in MSBuild 12.0.
Public method ToString (Inherited from Object.)

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Remarks

This abstract class provides default implementations for the methods and properties of the ILogger interface.

This class can only be instantiated in a derived form.

Examples

The following example shows how to write a basic logger that responds to build events.

using System;
using System.IO;
using System.Security;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;

namespace MyLoggers
{
    // This logger will derive from the Microsoft.Build.Utilities.Logger class, 
    // which provides it with getters and setters for Verbosity and Parameters, 
    // and a default empty Shutdown() implementation. 
    public class BasicFileLogger : Logger
    {
        /// <summary> 
        /// Initialize is guaranteed to be called by MSBuild at the start of the build 
        /// before any events are raised. 
        /// </summary> 
        public override void Initialize(IEventSource eventSource)
        {
            // The name of the log file should be passed as the first item in the 
            // "parameters" specification in the /logger switch.  It is required
            // to pass a log file to this logger. Other loggers may have zero or more than  
            // one parameters. 
            if (null == Parameters)
            {
                throw new LoggerException("Log file was not set.");
            }
            string[] parameters = Parameters.Split(';');
            
            string logFile = parameters[0];
            if (String.IsNullOrEmpty(logFile))
            {
                throw new LoggerException("Log file was not set.");
            }
            
            if (parameters.Length > 1)
            {
                throw new LoggerException("Too many parameters passed.");
            }
            
            try
            {
                // Open the file 
                this.streamWriter = new StreamWriter(logFile);
            }
            catch (Exception ex)
            {
                if
                (
                    ex is UnauthorizedAccessException
                    || ex is ArgumentNullException
                    || ex is PathTooLongException
                    || ex is DirectoryNotFoundException
                    || ex is NotSupportedException
                    || ex is ArgumentException
                    || ex is SecurityException
                    || ex is IOException
                )
                {
                    throw new LoggerException("Failed to create log file: " + ex.Message);
                }
                else
                {
                    // Unexpected failure 
                    throw;
                }
            }

            // For brevity, we'll only register for certain event types. Loggers can also 
            // register to handle TargetStarted/Finished and other events.
            eventSource.ProjectStarted += new ProjectStartedEventHandler(eventSource_ProjectStarted);
            eventSource.TaskStarted += new TaskStartedEventHandler(eventSource_TaskStarted);
            eventSource.MessageRaised += new BuildMessageEventHandler(eventSource_MessageRaised);
            eventSource.WarningRaised += new BuildWarningEventHandler(eventSource_WarningRaised);
            eventSource.ErrorRaised += new BuildErrorEventHandler(eventSource_ErrorRaised);
            eventSource.ProjectFinished += new ProjectFinishedEventHandler(eventSource_ProjectFinished);
        }

        void eventSource_ErrorRaised(object sender, BuildErrorEventArgs e)
        {
            // BuildErrorEventArgs adds LineNumber, ColumnNumber, File, amongst other parameters 
            string line = String.Format(": ERROR {0}({1},{2}): ", e.File, e.LineNumber, e.ColumnNumber);
            WriteLineWithSenderAndMessage(line, e);
        }
        
        void eventSource_WarningRaised(object sender, BuildWarningEventArgs e)
        {
            // BuildWarningEventArgs adds LineNumber, ColumnNumber, File, amongst other parameters 
            string line = String.Format(": Warning {0}({1},{2}): ", e.File, e.LineNumber, e.ColumnNumber);
            WriteLineWithSenderAndMessage(line, e);
        }

        void eventSource_MessageRaised(object sender, BuildMessageEventArgs e)
        {
            // BuildMessageEventArgs adds Importance to BuildEventArgs 
            // Let's take account of the verbosity setting we've been passed in deciding whether to log the message 
            if ((e.Importance == MessageImportance.High && IsVerbosityAtLeast(LoggerVerbosity.Minimal))
                || (e.Importance == MessageImportance.Normal && IsVerbosityAtLeast(LoggerVerbosity.Normal))
                || (e.Importance == MessageImportance.Low && IsVerbosityAtLeast(LoggerVerbosity.Detailed))              
                )
            {
                WriteLineWithSenderAndMessage(String.Empty, e);
            }
        }

        void eventSource_TaskStarted(object sender, TaskStartedEventArgs e)
        {
            // TaskStartedEventArgs adds ProjectFile, TaskFile, TaskName 
            // To keep this log clean, this logger will ignore these events.
        }
        
        void eventSource_ProjectStarted(object sender, ProjectStartedEventArgs e)
        {
            // ProjectStartedEventArgs adds ProjectFile, TargetNames 
            // Just the regular message string is good enough here, so just display that.
            WriteLine(String.Empty, e);
            indent++;
        }

        void eventSource_ProjectFinished(object sender, ProjectFinishedEventArgs e)
        {
            // The regular message string is good enough here too.
            indent--;
            WriteLine(String.Empty, e);
        }
        
        /// <summary> 
        /// Write a line to the log, adding the SenderName and Message 
        /// (these parameters are on all MSBuild event argument objects) 
        /// </summary> 
        private void WriteLineWithSenderAndMessage(string line, BuildEventArgs e)
        {
            if (0 == String.Compare(e.SenderName, "MSBuild", true /*ignore case*/))
            {
                // Well, if the sender name is MSBuild, let's leave it out for prettiness
                WriteLine(line, e);
            }
            else
            {
                WriteLine(e.SenderName + ": " + line, e);
            }
        }
        
        /// <summary> 
        /// Just write a line to the log 
        /// </summary> 
        private void WriteLine(string line, BuildEventArgs e)
        {
            for (int i = indent; i > 0; i--)
            {
                streamWriter.Write("\t");
            }
            streamWriter.WriteLine(line + e.Message);
        }
        
        /// <summary> 
        /// Shutdown() is guaranteed to be called by MSBuild at the end of the build, after all  
        /// events have been raised. 
        /// </summary> 
        public override void Shutdown()
        {
            // Done logging, let go of the file
            streamWriter.Close();
        }

        private StreamWriter streamWriter;
        private int indent;
    }
}

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

Microsoft.Build.Utilities Namespace