package io.ultrabrew.metrics.examples.listeners;
import io.ultrabrew.metrics.Reporter;
import io.ultrabrew.metrics.examples.MyApp;
import io.ultrabrew.metrics.reporters.SLF4JReporter;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
/**
* A context lifecycle listener, used to initialize and shutdown metrics reporting.
*/
@WebListener
public class MetricsInitializer implements ServletContextListener {
private static final String REPORTER_ATTRIBUTE = "io.ultrabrew.metrics.examples.reporter";
@Override
public void contextInitialized(ServletContextEvent sce) {
// Create a reporter and add it to the registry.
// For demo purposes we use SLF4JReporter which should not be used for production systems
SLF4JReporter reporter = SLF4JReporter.builder().withName("example").withStepSize(10).build();
MyApp.metricRegistry.addReporter(reporter);
sce.getServletContext().setAttribute(REPORTER_ATTRIBUTE, reporter);
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// Clean up the reporter here to avoid leaking resources
SLF4JReporter reporter = (SLF4JReporter) sce.getServletContext()
.getAttribute(REPORTER_ATTRIBUTE);
reporter.close();
}
}
