D-Net

package eu.dnetlib.metrics;

import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import io.prometheus.client.Counter;

import org.springframework.stereotype.Component;

import org.springframework.web.method.HandlerMethod;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

@Component

public class RequestCounterInterceptor extends HandlerInterceptorAdapter implements MetricInterceptor {

	private static final Counter requestTotal = Counter.build()

			.name("http_requests_total")

			.labelNames("method", "handler", "status")

			.help("Http Request Total").register();

	@Override

	public void afterCompletion(final HttpServletRequest request, final HttpServletResponse response, final Object handler, final Exception e) throws Exception {

		String handlerLabel = handler.toString();

		// get short form of handler method name

		if (handler instanceof HandlerMethod) {

			Method method = ((HandlerMethod) handler).getMethod();

			handlerLabel = method.getDeclaringClass().getSimpleName() + "." + method.getName();

		}

		requestTotal.labels(

				request.getMethod(),

				handlerLabel,

				Integer.toString(response.getStatus())).inc();

	}

}