Instrumentation in Visual C#.NET

Encoding Data Matrix in Visual C#.NET Instrumentation

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21. Press Enter to terminate the application. Although the application has finished, the trace information is still available. 22. To view it, launch the Service Trace Viewer tool by clicking Start. From the All Programs menu, choose Microsoft Windows SDK V6.1. Select Tools, and then click Service Trace Viewer. 23. In Service Trace Viewer, choose Open from the File menu. Navigate to the <InstallHome> /6/Lesson2/Exercise2/<language>/Before/TestClient/bin/Debug directory and open the Traces.svclog file. 24. After the log file has been opened, ensure that the Activity tab on the left side is selected. You will see that there are two activities, named DemoService Activity and GetHeader Activity. Select the DemoService Activity node. 25. On the top right, a list of the details for DemoService Activity appears, as shown in Figure 6-4. You should be able to see the start for DemoService and that a transfer to GetHeader Activity occurred.

Figure 6-4

26. Double-click the To: GetHeader Activity node. The contents of the top right pane change to display the details for GetHeader Activity. The incoming transfer is noted, along with the start, the informational messages, the outgoing transfer, and the stop. 27. Choose Add from the File menu. Navigate to the <InstallHome>/6/Lesson2 /Exercise2/<language>/Before/DemoService/bin/Debug directory.

There you will find a file that starts with a GUID and ends with Traces.svclog. This is the service side of the log file. 28. Select that file and click Open. The pane on the left hasn t changed. However, the pane in the top right has had a few lines added. These are the trace messages from the service side that were correlated to GetHeader Activity. Figure 6-5 illustrates the combined log files.

Figure 6-5

These include the start and stop events along with the informational messages emitted by the service. For example, in the top right pane, you see two GetHeader Activitiy entries marked as having a Start level. These are the client and service activity boundaries. You can use Process Name or Thread Id to distinguish between the two sides.

You can use activities to correlate traces across service boundaries. The propagation of activities across service boundaries depends on both the proper instrumentation of the application code and the appropriate configuration of WCF. Although activities must be created by hand, the resulting traces can be viewed through the Service Trace Viewer.

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You can use the following questions to test your knowledge of the information in Lesson 2. The questions are also available on the companion CD if you prefer to review them in electronic form.

Answers to these questions and explanations of why each answer choice is correct or incorrect are located in the Answers section at the end of the book.

1. You have created a WCF application. You would like to implement end-to-end tracing. You believe you have done so, but when you look at the Service Trace Viewer, the client and service traces do not appear to be correlated. Moreover, when you check the Trace.CorrelationManager.ActivityId property in the service, it is not the same as in the client. Which of the following is NOT a potential solution to this problem A. The switchValue attribute for the System.ServiceModel source is not set to ActivityTracing. B. In the client side, the Trace.CorrelationManager.ActivityId has not been assigned a new GUID value. C. The propagateActivity attribute in the System.ServiceModel source has not been set to true. D. A Transfer trace has not been emitted on the client. 2. You are designing an activity to correlate functionality across multiple clients and services. Specifically, a client sends a request to a service, which then sends a request to a different service. This last service is not in your control, so you don t want the trace information generated by the service to be included in your activity. Which of the following methods should be called immediately prior to invoking the third-party service A. Trace.TraceEvent(TraceEvent.Start, 0, My Activity ) B. Trace.TraceEvent(TraceEvent.Stop, 0, My Activity ) C. Trace.TraceEvent(TraceEvent.Suspend, 0, My Activity ) D. Trace.TraceEvent(TraceEvent.Transfer, 0, My Activity )