Adding EventIds when logging to WADLogs

This is a great article on how to include an event id in the WADLogs table.

The trick is to use a custom trace source as follows

TraceSource ts = new TraceSource(“My Custom Event Source Name”, SourceLevels.Information);

ts.TraceEvent(TraceEventType.Warning, 102, “This is a test log using trace source”);

and then to configure the azure listener to get this into the appropriate log file:

This gets added to the appropriate system.diagonstics section:


<source name=”MyTraceSource” switchName=”sourceSwitch” switchType=”System.Diagnostics.SourceSwitch”>


<add type=”Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener, Microsoft.WindowsAzure.Diagnostics, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35″ name=”AzureDiagnostics”>

<filter type=”” />






<add name=”sourceSwitch” value=”Warning”/>


The big advantage of this is that you get to assign your own error codes to the messages.

Practically all of the default Azure stuff will be coded as zero.

This means that you can assign defined ranges of code to indicate that these are for example:

Timing Messages.

Notification for information.

Notification for action.

These make analysing the logs much easier.

Btw are you aware of the WADLogs powershell trick:

“0” + [DateTime]::UtcNow.AddHours(-1).Ticks

This gives a partition key of an hour ago.

This is great for getting extracted logs.

Extract the logs into csv and use the powershell import-csv command.

This is an amazingly fast way of analysing logs.

Logging Analytics

On my current project I have found an urgent need to improve the general instrumentation.

This started by adding a few useful trace statements that will show how long certain key operations will take.

Typically this will involve reading some logs (or in fact querying the WADLogsTable).

I have just realised that without some useful log reporting queries then I am just setting myself up for a lot of manual work.

Indeed on a large scale system there is no point in adding logging unless you have something that can read and display these in a useful form.

I am wonding about the analysis side. I have seen lots of articles about writing logging but very little on reading logging.

I am thinking of having a set of classes that act like reports to perform prebaked queries on WADLogs. These could expose this data as restful web services allowing other applications (powershell scripts, excel, reporting services…) to display the data.

Here is an article on logging analytics.