Request Timeouts

    • Deploy the sample application including the default destination rules.

    • Initialize the application version routing by running the following command:

    A timeout for HTTP requests can be specified using the timeout field of the route rule. By default, the request timeout is disabled, but in this task you override the service timeout to 1 second. To see its effect, however, you also introduce an artificial 2 second delay in calls to the ratings service.

    1. Route requests to v2 of the reviews service, i.e., a version that calls the ratings service:

    3. Now add a half second request timeout for calls to the service:

    4. Refresh the Bookinfo web page.

      You should now see that it returns in about 1 second, instead of 2, and the reviews are unavailable.

      The reason that the response takes 1 second, even though the timeout is configured at half a second, is because there is a hard-coded retry in the productpage service, so it calls the timing out reviews service twice before returning.

    You observed that instead of displaying reviews, the Bookinfo product page (which calls the reviews service to populate the page) displayed the message: Sorry, product reviews are currently unavailable for this book. This was the result of it receiving the timeout error from the reviews service.

    If you examine the , you’ll find out that the productpage microservice also has its own application-level timeout (3 seconds) for calls to the reviews microservice. Notice that in this task you used an Istio route rule to set the timeout to half a second. Had you instead set the timeout to something greater than 3 seconds (such as 4 seconds) the timeout would have had no effect since the more restrictive of the two takes precedence. More details can be found here.

    One more thing to note about timeouts in Istio is that in addition to overriding them in route rules, as you did in this task, they can also be overridden on a per-request basis if the application adds an header on outbound requests. In the header, the timeout is specified in milliseconds instead of seconds.

    • Remove the application routing rules:

    • If you are not planning to explore any follow-on tasks, see the Bookinfo cleanup instructions to shutdown the application.