Logging TraceListener Improved

March 11, 2005

I made a few improvements to the Logging TraceListener:

• Files can now be aged by date as well as size
• Filename is now completely templated using a single FileNameTemplate property, which supports standard String.Format codes for file number and date
• Added seperate properties to specify units of scale for age and size (kb, month, gb, week)
• Default limit changed to 1mb maximum size, no age limit, no file count limit

Here's how the new options look when set it up via the .config file:

<!-- this enables IIS-style logging of console output -->
<system.diagnostics>
  <trace autoflush="true" indentsize="4">
    <listeners>
      <add name="CyclicLog" 
        type="ConsoleApp.CyclicLogTraceListener,ConsoleApp" 
        initializeData="fileCountThreshold=10, fileSizeThreshold=512, 
        fileSizeUnit=kilobytes, fileAgeThreshold=1, fileAgeUnit=months, 
        fileNameTemplate='console-{1:MMM-yy}-{0:0000}.log'" />
    </listeners>
  </trace>
</system.diagnostics>

And here's how it looks when created manually:

_HtmlLogger = New CyclicLogTraceListener
With _HtmlLogger
    .TimeStampFormat = ""
    .FileNameTemplate = "html-{1:MMM-yy}-{0:0000}.log"
    .FileAgeThreshold = 1
    .FileAgeUnit = CyclicLogTraceListener.AgeUnit.Months
    .FileCountThreshold = 3
End With

I did this to get a seperate, private log file for the large amounts of HTML I wanted to trace. Including them with the regular console output is way too noisy. I combined age, number, and size limits, so I end up with something like this:

html-Feb-05-0000.log        (1mb)
html-Feb-05-0001.log        (1mb)
html-Mar-05-0000.log        (1mb)
console-Feb-05-0000.log   (512kb)
console-Mar-05-0000.log   (512kb)

With the configuration specified above, no more than 3 logs will ever exist, and no more than 3 per month, and never more than 512kb or 1mb in size.