Metrics: collect metrics after the response is complete (#1104)

Author: Linas Zvirblis

modules/jooby-metrics/src/main/java/org/jooby/metrics/InstrumentedHandler.java

@@ -206,7 +206,6 @@
 import org.jooby.Request;
 import org.jooby.Response;
 import org.jooby.Route;
-import org.jooby.Route.Chain;
 import org.jooby.Status;
 
 import com.codahale.metrics.Counter;
@@ -220,22 +219,22 @@
  * @author edgar
  * @since 0.13.0
  */
-public class InstrumentedHandler implements Route.Filter {
+public class InstrumentedHandler implements Route.Handler {
 
   @Override
-  public void handle(final Request req, final Response rsp, final Chain chain) throws Throwable {
+  public void handle(final Request req, final Response rsp) throws Throwable {
     MetricRegistry registry = req.require(MetricRegistry.class);
     Counter counter = registry.counter("request.actives");
     Timer.Context timer = registry.timer("request").time();
-    try {
-      counter.inc();
-      chain.next(req, rsp);
-    } finally {
+
+    counter.inc();
+
+    rsp.complete((ereq, ersp, x) -> {
       timer.stop();
       counter.dec();
       Meter meter = registry.meter("responses." + rsp.status().orElse(Status.OK).value());
       meter.mark();
-    }
+    });
   }
 
 }

modules/jooby-metrics/src/test/java/org/jooby/metrics/InstrumentedHandlerTest.java

@@ -22,6 +22,16 @@
 
 public class InstrumentedHandlerTest {
 
+  private Block capture = unit -> {
+    Response rsp = unit.get(Response.class);
+    rsp.complete(unit.capture(Route.Complete.class));
+  };
+
+  private Block onComplete = unit -> {
+    unit.captured(Route.Complete.class).iterator().next()
+        .handle(unit.get(Request.class), unit.get(Response.class), Optional.empty());
+  };
+
   private Block registry = unit -> {
     Request request = unit.get(Request.class);
     expect(request.require(MetricRegistry.class))
@@ -80,12 +90,13 @@ public void instrument() throws Exception {
         .expect(registry)
         .expect(counter)
         .expect(timer)
+        .expect(capture)
         .expect(meter)
         .expect(next)
         .run(unit -> {
           new InstrumentedHandler().handle(unit.get(Request.class), unit.get(Response.class),
               unit.get(Route.Chain.class));
-        });
+        }, onComplete);
   }
 
   @Test(expected = IOException.class)
@@ -94,12 +105,13 @@ public void instrumentWithErr() throws Exception {
         .expect(registry)
         .expect(counter)
         .expect(timer)
+        .expect(capture)
         .expect(meter)
         .expect(nextErr)
         .run(unit -> {
           new InstrumentedHandler().handle(unit.get(Request.class), unit.get(Response.class),
               unit.get(Route.Chain.class));
-        });
+        }, onComplete);
   }
 
 }