Cloud Trace

Trace Overview

Cloud Trace (documentation) enables developers to see distributed traces that visually expose latency bottleneck in requests. Developers instrument application code to collect trace information. You can also include environmental information in traces and trace information can be included in Cloud Logging logs. The Trace UI can then pull relevant log events into the trace timelines.

For instrumenting your applications, currently recommended solution is OpenCensus. OpenCensus is an open-source project that supports trace instrumentation in a variety of languages and that can export this data to Cloud Operations. Then you can use the Cloud Trace UI to analyze the data. Note that OpenCensus is merging with another similar project, OpenTracing, to form OpenTelemetry. See OpenCensus to become OpenTelemetry in this doc.

HipsterShop microservices are instrumented to collect trace data. In addition to distributed tracing, OpenCensus (Stats) provides the sink to send quantifiable data, such as database latency, open file descriptors, and so on, that helps to set up monitoring of SLIs and SLOs for the service. This data is available in Cloud Monitoring, and HipsterShop microservices are also instrumented to collect this kind of data.

Using Trace

To bring up Cloud Trace, click Trace in the GCP navigation panel. This takes you to the Trace Overview page, where you see the traces generated by the Sandbox microservices:

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Click Trace List in the navigation panel to get the list of traces captured during a particular time:

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Click on any trace in the timeline to get a detailed view and breakdown of the traced call and the subsequent calls that were made:

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Finally, click Analysis Reports in the navigation menu to see a list of reports that are generated.

If you have just set up the Sandbox environment, you may not have any reports. Click on New Report to create one. An example of a first report: in the Request Filter field, select Recv./cart. Leave the other options the default. Once the report is created, you should be able to see it in the Analysis Reports list.

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View one of the reports that was created (or the one you created yourself) to understand either the density or cumulative distribution of latency for the call you selected:

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Feel free to explore the tracing data collected from here before moving on to the next section.