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/**
* Copyright 2019 VMware, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.micrometer.core.instrument.binder.jetty;
import io.micrometer.core.instrument.*;
import io.micrometer.core.instrument.binder.BaseUnits;
import io.micrometer.core.instrument.binder.http.DefaultHttpServletRequestTagsProvider;
import io.micrometer.core.instrument.binder.http.HttpServletRequestTagsProvider;
import io.micrometer.core.lang.NonNullApi;
import io.micrometer.core.lang.NonNullFields;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.jetty.server.AsyncContextEvent;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.HttpChannelState;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.HandlerWrapper;
import org.eclipse.jetty.util.FutureCallback;
import org.eclipse.jetty.util.component.Graceful;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Adapted from Jetty's StatisticsHandler.
*
* @author Jon Schneider
* @since 1.4.0
*/
@NonNullApi
@NonNullFields
public class TimedHandler extends HandlerWrapper implements Graceful {
private static final String SAMPLE_REQUEST_TIMER_ATTRIBUTE = "__micrometer_timer_sample";
private static final String SAMPLE_REQUEST_LONG_TASK_TIMER_ATTRIBUTE = "__micrometer_ltt_sample";
private final MeterRegistry registry;
private final Iterable tags;
private final HttpServletRequestTagsProvider tagsProvider;
private final Shutdown shutdown = new Shutdown() {
@Override
protected FutureCallback newShutdownCallback() {
return TimedHandler.this.newShutdownCallback();
}
};
private final LongTaskTimer openRequests;
private final Counter asyncDispatches;
private final Counter asyncExpires;
private final AtomicInteger asyncWaits = new AtomicInteger();
public TimedHandler(MeterRegistry registry, Iterable tags) {
this(registry, tags, new DefaultHttpServletRequestTagsProvider());
}
public TimedHandler(MeterRegistry registry, Iterable tags, HttpServletRequestTagsProvider tagsProvider) {
this.registry = registry;
this.tags = tags;
this.tagsProvider = tagsProvider;
this.openRequests = LongTaskTimer.builder("jetty.server.dispatches.open")
.description("Jetty dispatches that are currently in progress")
.tags(tags)
.register(registry);
this.asyncDispatches = Counter.builder("jetty.server.async.dispatches")
.description("Asynchronous dispatches")
.tags(tags)
.register(registry);
this.asyncExpires = Counter.builder("jetty.server.async.expires")
.description("Asynchronous operations that timed out before completing")
.tags(tags)
.register(registry);
Gauge.builder("jetty.server.async.waits", asyncWaits, AtomicInteger::doubleValue)
.description("Pending asynchronous wait operations")
.baseUnit(BaseUnits.OPERATIONS)
.tags(tags)
.register(registry);
}
@Override
public void handle(String path, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
Timer.Sample sample = Timer.start(registry);
LongTaskTimer.Sample requestSample;
HttpChannelState state = baseRequest.getHttpChannelState();
if (state.isInitial()) {
requestSample = openRequests.start();
request.setAttribute(SAMPLE_REQUEST_TIMER_ATTRIBUTE, sample);
request.setAttribute(SAMPLE_REQUEST_LONG_TASK_TIMER_ATTRIBUTE, requestSample);
} else {
asyncDispatches.increment();
request.setAttribute(SAMPLE_REQUEST_TIMER_ATTRIBUTE, sample);
requestSample = (LongTaskTimer.Sample) request.getAttribute(SAMPLE_REQUEST_LONG_TASK_TIMER_ATTRIBUTE);
}
try {
Handler handler = getHandler();
if (handler != null && !shutdown.isShutdown() && isStarted()) {
handler.handle(path, baseRequest, request, response);
} else {
if (!baseRequest.isHandled()) {
baseRequest.setHandled(true);
}
if (!baseRequest.getResponse().isCommitted()) {
response.sendError(HttpStatus.SERVICE_UNAVAILABLE_503);
}
}
} finally {
if (state.isSuspended()) {
if (state.isInitial()) {
state.addListener(onCompletion);
asyncWaits.incrementAndGet();
}
} else if (state.isInitial()) {
sample.stop(Timer.builder("jetty.server.requests")
.description("HTTP requests to the Jetty server")
.tags(tagsProvider.getTags(request, response))
.tags(tags)
.register(registry));
requestSample.stop();
// If we have no more dispatches, should we signal shutdown?
FutureCallback shutdownCallback = shutdown.get();
if (shutdownCallback != null) {
response.flushBuffer();
if (openRequests.activeTasks() == 0) {
shutdownCallback.succeeded();
}
}
}
// else onCompletion will handle it.
}
}
private final AsyncListener onCompletion = new OnCompletionAsyncListener(this);
@Override
protected void doStart() throws Exception {
shutdown.cancel();
super.doStart();
}
@Override
protected void doStop() throws Exception {
shutdown.cancel();
super.doStop();
}
@Override
public Future shutdown() {
return shutdown.shutdown();
}
@Override
public boolean isShutdown() {
return shutdown.isShutdown();
}
void onAsyncTimeout(AsyncEvent event) {
asyncExpires.increment();
HttpChannelState state = ((AsyncContextEvent) event).getHttpChannelState();
Request request = state.getBaseRequest();
LongTaskTimer.Sample lttSample = (LongTaskTimer.Sample) request.getAttribute(SAMPLE_REQUEST_LONG_TASK_TIMER_ATTRIBUTE);
lttSample.stop();
}
void onAsyncComplete(AsyncEvent event) {
HttpChannelState state = ((AsyncContextEvent) event).getHttpChannelState();
Request request = state.getBaseRequest();
Timer.Sample sample = (Timer.Sample) request.getAttribute(SAMPLE_REQUEST_TIMER_ATTRIBUTE);
LongTaskTimer.Sample lttSample = (LongTaskTimer.Sample) request.getAttribute(SAMPLE_REQUEST_LONG_TASK_TIMER_ATTRIBUTE);
if (sample != null) {
sample.stop(Timer.builder("jetty.server.requests")
.description("HTTP requests to the Jetty server")
.tags(tagsProvider.getTags(request, request.getResponse()))
.tags(tags)
.register(registry));
lttSample.stop();
}
asyncWaits.decrementAndGet();
// If we have no more dispatches, should we signal shutdown?
FutureCallback shutdownCallback = shutdown.get();
if (shutdownCallback != null && openRequests.activeTasks() == 0) {
shutdownCallback.succeeded();
}
}
private FutureCallback newShutdownCallback() {
return new FutureCallback(openRequests.activeTasks() == 0);
}
}