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POc# windows-services - How do I handle logging exceptions?
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copied!<p>I am creating a Windows service. When an exception occurrs, I handle it appropriately and create a log. I am using the <a href="http://en.wikipedia.org/wiki/Decorator_pattern" rel="nofollow noreferrer">decorator pattern</a>, as there are many different ways people will be looking at these logs. I have an email logger, a file logger, and a windows event logger, all which inherit from LoggingDecorator, which implements ILogger. So, no logger knows about any other logger.</p> <p>My question is: How should I handle logging exceptions? </p> <p>If writing to a file fails, or sending an email fails, what should I do? I want to log the initial log content with the other loggers, but what do I do with the logging exception? Doesn't it also depend on the order of the loggers in the constructor?</p> <p>Right now, I'm just wrapping try/catch blocks with empty catch(Exception) statements, which just feels dirty and makes FxCop yell at me. However, is this one of those <a href="https://stackoverflow.com/questions/21938/is-it-really-that-bad-to-catch-a-general-exception">"it depends"</a> moments?</p> <pre><code>[Flags] public enum LoggingCategories { None = 0, ServiceEvents = 1, ProcessingInformation = 2, ProcessingErrors = 4, UnexpectedErrors = 8 } public interface ILogger { void LogMessage(LoggingCategories category, string message); } public abstract class LoggerDecorator : ILogger { private ILogger _decoratedLogger; private LoggingCategories _categories; protected LoggerDecorator(ILogger logger, LoggingCategories categories) { this._decoratedLogger = logger; this._categories = categories; } protected bool ShouldLogCategory(LoggingCategories category) { return ((this._categories & category) == category); } public virtual void LogMessage(LoggingCategories category, string message) { _decoratedLogger.LogMessage(category, message); } } public class ControlLogger : ILogger { public ControlLogger() { } public void LogMessage(LoggingCategories category, string message) { Console.WriteLine(LoggingHelper.ConstructLog(category, message)); } } </code></pre> <p>(questionable code in WindowsEventLogger)</p> <pre><code>try { this._eventLog.WriteEntry(log, type); } catch (Exception) { //Even if this logging fails, we do not want to halt any further logging/processing. } </code></pre> <p>(code in service constructor)</p> <pre><code>ILogger controlLogger = new ControlLogger(); ILogger windowsEventLogger = new WindowsEventLogger(controlLogger, windowsEventLogCategories, windowsEventLogSource); ILogger emailLogger = new EmailLogger(windowsEventLogger, emailCategories, emailSubject, emailAddresses); ILogger fileLogger = new FileLogger(emailLogger, fileCategories, logDirectory, logFileNamePrefix, logFileExtension); this._logger = fileLogger; </code></pre>

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