IEventSource Interface
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
This interface defines the events raised by the build engine. Loggers use this interface to subscribe to the events they are interested in receiving.
public interface class IEventSourcepublic interface IEventSourcetype IEventSource = interfacePublic Interface IEventSource- Derived
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;
}
}
Events
| AnyEventRaised |
this event is raised to log any build event. These events do not include telemetry. To receive telemetry, you must attach to the TelemetryLogged event. |
| BuildFinished |
this event is raised to log the end of a build |
| BuildStarted |
this event is raised to log the start of a build |
| CustomEventRaised |
this event is raised to log custom events |
| ErrorRaised |
this event is raised to log an error |
| MessageRaised |
this event is raised to log a message |
| ProjectFinished |
this event is raised to log the end of a project build |
| ProjectStarted |
this event is raised to log the start of a project build |
| StatusEventRaised |
this event is raised to log any build status event |
| TargetFinished |
this event is raised to log the end of a target build |
| TargetStarted |
this event is raised to log the start of a target build |
| TaskFinished |
this event is raised to log the end of task execution |
| TaskStarted |
this event is raised to log the start of task execution |
| WarningRaised |
this event is raised to log a warning |