Enabling/Disabling WCF Trace without changing the config files

Question

User-1716690740 posted

Hi , Is there a way to enable/disable the WCF trace/logging for a perticular end point without changing the web.config ?

Answer 1

User-837620913 posted

With WCF 4 and later you can activate Event Tracing for Windows (ETW) without modifying the app. See this guide: http://msdn.microsoft.com/en-us/library/dd764466.aspx

You can also write code to change the tracing level. Here is an example: http://wcfpro.wordpress.com/2010/11/21/how-to-add-wcf-traces-programmatically/

Answer 2

User-1635195291 posted

Hi sk_aspnet,

Please go through the links below:

• How to Enable/Disable WCF Tracing through Code - MSDN
• How to enable WCF tracing
• WCF Service - Simple steps to enable tracing

1.Create our normal WCF sources for logging in config file

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.diagnostics>
        <sources>
            <source name="System.ServiceModel" switchValue="Warning,ActivityTracing">
                <listeners>
                    <add name="CustomListner"/>
                </listeners>
            </source>
          <source name="System.ServiceModel.MessageLogging" switchValue="Warning, ActivityTracing">
            <listeners>
              <add name="CustomListner" />
            </listeners>
          </source>
        </sources>
        <sharedListeners>
            <add  type="WCFTracing.CustomTraceListner, WCFTracing, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
                name="CustomListner" />
        </sharedListeners>
      <trace autoflush="true" />
    </system.diagnostics>
    <system.serviceModel>
        <diagnostics>
            <messageLogging logEntireMessage="true" logKnownPii="true" logMalformedMessages="true"
                logMessagesAtServiceLevel="true" />
            <endToEndTracing activityTracing="true" />
        </diagnostics>
    </system.serviceModel>
</configuration>

2. Create a custom listner class which is mentioned in the config. Please note the function "CheckIfAllowed". This actually returns a memory stream  in case logging is turned off. This ensures that the constructor doesn't fail and also no file is generated. Also, we are limiting buffer of memory stream to 2 bytes.And that's it. You can view the file using svctraceviewer conveniently.

public class CustomTraceListner : XmlWriterTraceListener
    {
        public CustomTraceListner()
            : base(CheckIfAllowed())
        {
 
        }
        private static Stream CheckIfAllowed()
        {
            bool ifAllowed = true;
            if (ifAllowed)
                return new FileStream(@"D:\temp.svclog", FileMode.OpenOrCreate, FileAccess.Write);
             return new MemoryStream(2);
        }
    }
 

Hope this helps.

Thanks,

Jatin

Answer 3

User-1716690740 posted

Thanks for your post . I am hosting my wcf in IIS ; The turnoff and turnon switch is not working for me ;

Below is the code

    

namespace WCFTracing
{
public class CustomTraceListner : XmlWriterTraceListener
{
public CustomTraceListner()
: base(CheckIfAllowed())
{

}

private static Stream CheckIfAllowed()
{
bool ifAllowed = isEnabled(@"C:\POC\WCFCustomListner\configdb.xml", "enabletrace");
if (ifAllowed)
{
return new FileStream(@"C:\POC\WCFCustomListner\Log\temp20.svclog", FileMode.OpenOrCreate);
}
else
{
return new MemoryStream(2);
}
}

private static bool isEnabled(string path, string elementName)
{
try
{
string elementValue = string.Empty;
bool returnVal = false;
using (XmlTextReader reader = new XmlTextReader(path))
{

reader.ReadToFollowing(elementName);
if (reader.Read())
elementValue = reader.Value;

}
if (!string.IsNullOrEmpty(elementValue))
{
bool.TryParse(elementValue, out returnVal);
}
return returnVal;

}
catch (Exception ex)
{
return false;
}
}

}

}

Answer 4

User-1716690740 posted

Hay Darell,

Thanks for your time and reply ;

The switch is not working in IIS hosted WCF . Let me know

Answer 5

User260886948 posted

Hi,

Have you tried the first solution post by @DarrellNorton? In my mind, it should work.

And I see that you have post a same question in: http://social.msdn.microsoft.com/Forums/en-US/67126bfe-74a2-418a-b7f2-2bd96424ef65/how-to-enable-wcf-traces-programmatically .

Please try to check the replies.

Best Regards,
Amy Peng