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MicroProfile Fault Tolerance - Timeout

This is an example of how to use Microprofile @Timeout in TomEE.

Timeout Feature

Fault Tolerance Timeout allow to specify how long a task can take to complete its execution and aborting it in case of timeout. Timeout feature can be used along with other annotations to guide the execution and result of a task.
Check the specification for more details.

Timeout annotation allows to configure :

  • value: the timeout value

  • unit: the timeout unit

Example

Run the application

mvn clean install tomee:run

How does it work?

The method statusOfDayByAccuWeather fails when the threshold of @Timeout annotation is reached due to a long execution of longProcessingTask method. To respond to the request nicely, a fallback method will take place to complete the request successfully. The fallback method is determined by @Fallback annotation.

@RequestScoped
public class WeatherGateway {

    private static final Logger LOGGER = Logger.getLogger(WeatherGateway.class.getName());

    @Timeout(50)
    @Fallback(fallbackMethod = "statusOfWeekByMetEireann")
    public String statusOfDayByAccuWeather(){
        return longProcessingTask();
    }

    public String statusOfWeekByMetEireann(){
        LOGGER.log(Level.WARNING, "MetEireann backup service has been requested due to AccuWeather timeout");
        return "Beautiful day";
    }

    private String longProcessingTask(){
        try {
            Thread.sleep(80);
        } catch (InterruptedException e) {
            LOGGER.log(Level.WARNING,"AccuWeather task has been interrupted.");
        }
        return null;
    }
    ...
}

Day status call

GET http://localhost:8080/mp-faulttolerance-timeout/weather/day/status

Server log

WARNING AccuWeather task has been interrupted.
WARNING MetEireann fallback service has been requested due to AccuWeather timeout.

Response

Beautiful day!

Running the test

You can also try it out using the WeatherServiceTest.java available in the project.

mvn clean test
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0