/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
*
* http://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 org.apache.brooklyn.policy.enricher;
import static com.google.common.base.Preconditions.checkState;
import java.net.URI;
import java.net.URL;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.brooklyn.api.entity.Entity;
import org.apache.brooklyn.api.entity.EntityLocal;
import org.apache.brooklyn.api.sensor.AttributeSensor;
import org.apache.brooklyn.api.sensor.Enricher;
import org.apache.brooklyn.api.sensor.SensorEvent;
import org.apache.brooklyn.api.sensor.SensorEventListener;
import org.apache.brooklyn.config.ConfigKey;
import org.apache.brooklyn.core.config.ConfigKeys;
import org.apache.brooklyn.core.enricher.AbstractEnricher;
import org.apache.brooklyn.core.entity.trait.Startable;
import org.apache.brooklyn.core.sensor.Sensors;
import org.apache.brooklyn.feed.http.HttpFeed;
import org.apache.brooklyn.feed.http.HttpPollConfig;
import org.apache.brooklyn.feed.http.HttpValueFunctions;
import org.apache.brooklyn.util.collections.MutableMap;
import org.apache.brooklyn.util.core.flags.SetFromFlag;
import org.apache.brooklyn.util.javalang.AtomicReferences;
import org.apache.brooklyn.util.javalang.Boxing;
import org.apache.brooklyn.util.javalang.JavaClassNames;
import org.apache.brooklyn.util.math.MathFunctions;
import org.apache.brooklyn.util.net.Urls;
import org.apache.brooklyn.util.text.StringFunctions;
import org.apache.brooklyn.util.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Function;
import com.google.common.base.Suppliers;
import com.google.common.reflect.TypeToken;
/**
* An Enricher which computes latency in accessing a URL.
* See comments on the methods in the static {@link #builder()} this exposes.
* <p>
* This is currently tested against relatively simple GET requests,
* optionally returned from sensors. It does not currently support POST
* and has limited support for https.
*/
//@Catalog(name="HTTP Latency Detector", description="An Enricher which computes latency in accessing a URL, normally by periodically polling that URL")
public class HttpLatencyDetector extends AbstractEnricher implements Enricher {
private static final Logger log = LoggerFactory.getLogger(HttpLatencyDetector.class);
public static final Duration LATENCY_WINDOW_DEFAULT_PERIOD = Duration.TEN_SECONDS;
@SetFromFlag("url")
public static final ConfigKey<?> URL = ConfigKeys.newStringConfigKey("latencyDetector.url");
@SuppressWarnings("serial")
@SetFromFlag("urlSensor")
public static final ConfigKey<AttributeSensor<?>> URL_SENSOR = ConfigKeys.newConfigKey(new TypeToken<AttributeSensor<?>>() {}, "latencyDetector.urlSensor");
@SuppressWarnings("serial")
@SetFromFlag("urlPostProcessing")
public static final ConfigKey<Function<String,String>> URL_POST_PROCESSING = ConfigKeys.newConfigKey(
new TypeToken<Function<String,String>>() {},
"latencyDetector.urlPostProcessing",
"Function applied to the urlSensor value, to determine the URL to use");
@SetFromFlag("rollup")
public static final ConfigKey<Duration> ROLLUP_WINDOW_SIZE = ConfigKeys.newConfigKey(Duration.class, "latencyDetector.rollup");
@SetFromFlag("requireServiceUp")
public static final ConfigKey<Boolean> REQUIRE_SERVICE_UP = ConfigKeys.newBooleanConfigKey("latencyDetector.requireServiceUp");
@SetFromFlag("period")
public static final ConfigKey<Duration> PERIOD = ConfigKeys.newConfigKey(Duration.class, "latencyDetector.period");
public static final AttributeSensor<Double> REQUEST_LATENCY_IN_SECONDS_MOST_RECENT = Sensors.newDoubleSensor(
"web.request.latency.last", "Request latency of most recent call, in seconds");
public static final AttributeSensor<Double> REQUEST_LATENCY_IN_SECONDS_IN_WINDOW = Sensors.newDoubleSensor(
"web.request.latency.windowed", "Request latency over time window, in seconds");
final AtomicBoolean serviceUp = new AtomicBoolean(false);
final AtomicReference<String> url = new AtomicReference<String>();
HttpFeed httpFeed = null;
public HttpLatencyDetector() { // for rebinding, and for EnricherSpec usage
}
protected HttpLatencyDetector(Map<?,?> flags) {
super(flags);
}
@Override
public void setEntity(EntityLocal entity) {
super.setEntity(entity);
initialize();
startSubscriptions(entity);
activateAdditionalEnrichers(entity);
if (log.isDebugEnabled())
log.debug(""+this+" enabled="+computeEnablement()+" when attached, subscribing to "+getAllSubscriptions());
updateEnablement();
}
// TODO use init()?
protected void initialize() {
checkState(getConfig(URL) != null ^ getConfig(URL_SENSOR) != null,
"Must set exactly one of url or urlSensor: url=%s; urlSensor=%s", getConfig(URL), getConfig(URL_SENSOR));
checkState(getConfig(URL_SENSOR) != null || getConfig(URL_POST_PROCESSING) == null,
"Must not set urlPostProcessing without urlSensor");
Object configValue = getConfig(URL);
if (configValue != null) {
url.set(configValue.toString());
}
httpFeed = HttpFeed.builder()
.entity(entity)
.period(getConfig(PERIOD))
.baseUri(Suppliers.compose(Urls.stringToUriFunction(), AtomicReferences.supplier(url)))
.poll(new HttpPollConfig<Double>(REQUEST_LATENCY_IN_SECONDS_MOST_RECENT)
.onResult(MathFunctions.divide(HttpValueFunctions.latency(), 1000.0d))
.setOnException(null))
.suspended()
.build();
if (getUniqueTag()==null)
uniqueTag = JavaClassNames.simpleClassName(getClass())+":"+
(getConfig(URL)!=null ? getConfig(URL) : getConfig(URL_SENSOR));
}
protected void startSubscriptions(EntityLocal entity) {
if (getConfig(REQUIRE_SERVICE_UP)) {
subscriptions().subscribe(entity, Startable.SERVICE_UP, new SensorEventListener<Boolean>() {
@Override
public void onEvent(SensorEvent<Boolean> event) {
if (AtomicReferences.setIfDifferent(serviceUp, Boxing.unboxSafely(event.getValue(), false))) {
log.debug(""+this+" updated on "+event+", "+"enabled="+computeEnablement());
updateEnablement();
}
}
});
// TODO would be good if subscription gave us the current value, rather than risking a race with code like this.
Boolean currentVal = entity.getAttribute(Startable.SERVICE_UP);
if (currentVal != null) {
AtomicReferences.setIfDifferent(serviceUp, currentVal);
}
}
AttributeSensor<?> urlSensor = getConfig(URL_SENSOR);
if (urlSensor!=null) {
subscriptions().subscribe(entity, urlSensor, new SensorEventListener<Object>() {
@Override
public void onEvent(SensorEvent<Object> event) {
Function<String, String> postProcessor = getConfig(URL_POST_PROCESSING);
String val = event.getValue().toString();
String newVal = (postProcessor != null) ? postProcessor.apply(val) : val;
if (AtomicReferences.setIfDifferent(url, newVal)) {
log.debug(""+this+" updated on "+event+", "+"enabled="+computeEnablement());
updateEnablement();
}
}
});
// TODO would be good if subscription gave us the current value, rather than risking a race with code like this.
Object currentVal = entity.getAttribute(urlSensor);
if (currentVal != null) {
Function<String, String> postProcessor = getConfig(URL_POST_PROCESSING);
String newVal = (postProcessor != null) ? postProcessor.apply(currentVal.toString()) : currentVal.toString();
if (AtomicReferences.setIfDifferent(url, newVal)) {
log.debug("{} updated url on initial connectionon, to {}", this, newVal);
}
}
}
}
protected void activateAdditionalEnrichers(EntityLocal entity) {
Duration rollupWindowSize = getConfig(ROLLUP_WINDOW_SIZE);
if (rollupWindowSize!=null) {
entity.enrichers().add(new RollingTimeWindowMeanEnricher<Double>(entity,
REQUEST_LATENCY_IN_SECONDS_MOST_RECENT, REQUEST_LATENCY_IN_SECONDS_IN_WINDOW,
rollupWindowSize));
}
}
/** refreshes whether the latency detection feed should be enabled,
* based on e.g. service up, the URL sensor, etc */
public void updateEnablement() {
if (computeEnablement()) {
httpFeed.resume();
} else {
httpFeed.suspend();
}
}
protected boolean computeEnablement() {
return (!getConfig(REQUIRE_SERVICE_UP) || serviceUp.get()) && (url.get()!=null);
}
@Override
public void destroy() {
super.destroy();
if (httpFeed != null) httpFeed.stop();
}
public static Builder builder() {
return new Builder();
}
public static class Builder {
boolean requireServiceUp = true;
Duration period = Duration.ONE_SECOND;
String url;
AttributeSensor<?> urlSensor;
Function<String, String> urlPostProcessing;
Duration rollupWindowSize = LATENCY_WINDOW_DEFAULT_PERIOD;
/** indicates that the HttpLatencyDetector should not require "service up";
* if using this, you must supply a URL sensor or the detector will not know when to run */
// or extend this Builder and the Detector to allow subscribing to additional sensors
public Builder noServiceUp() {
requireServiceUp = false;
return this;
}
/** sets how often to test for latency */
public Builder period(Duration period) {
this.period = period;
return this;
}
public Builder period(int amount, TimeUnit unit) {
return period(Duration.of(amount, unit));
}
/** supplies a constant URL which should be polled for latency,
* where this constant URL is known. typically the alternative
* {@link #url(AttributeSensor)} is used (but you cannot use both forms) */
public Builder url(String url) {
this.url = url;
return this;
}
/** @see #url(String) */
public Builder url(URL url) {
return url(url.toString());
}
/** @see #url(String) */
public Builder url(URI uri) {
return url(uri.toString());
}
/** supplies a sensor which indicates the URL this should parse (e.g. ROOT_URL) */
public Builder url(AttributeSensor<?> sensor) {
this.urlSensor = sensor;
return this;
}
/** supplies a sensor which indicates the URL which this should parse (e.g. ROOT_URL),
* with post-processing, e.g. {@link StringFunctions#append(String)} */
public Builder url(AttributeSensor<?> sensor, Function<String, String> postProcessing) {
this.urlSensor = sensor;
this.urlPostProcessing = postProcessing;
return this;
}
/** specifies a size of the time window which should be used to give a rolled-up average;
* defaults to {@link HttpLatencyDetector#LATENCY_WINDOW_DEFAULT_PERIOD} */
public Builder rollup(Duration windowSize) {
this.rollupWindowSize = windowSize;
return this;
}
/** see {@link #rollup(Duration)} */
public Builder rollup(int windowSize, TimeUnit unit) {
return rollup(Duration.of(windowSize, unit));
}
/** specifies that a rolled-up average should _not_ be calculated and emitted
* (defaults to true) */
public Builder rollupOff() {
this.rollupWindowSize = null;
return this;
}
/** returns the detector. note that callers should then add this to the entity,
* typically using {@link Entity#addEnricher(Enricher)} */
public HttpLatencyDetector build() {
return new HttpLatencyDetector(MutableMap.builder()
.putIfNotNull(PERIOD, period)
.putIfNotNull(ROLLUP_WINDOW_SIZE, rollupWindowSize)
.putIfNotNull(REQUIRE_SERVICE_UP, requireServiceUp)
.putIfNotNull(URL, url)
.putIfNotNull(URL_SENSOR, urlSensor)
.putIfNotNull(URL_POST_PROCESSING, urlPostProcessing)
.build());
}
}
}