org.apache.flink.runtime.rest.handler.legacy.metrics.AbstractAggregatingMetricsHandler Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.rest.handler.legacy.metrics;
import org.apache.flink.runtime.jobmaster.JobManagerGateway;
import org.apache.flink.runtime.rest.handler.legacy.AbstractJsonRequestHandler;
import org.apache.flink.runtime.rest.handler.legacy.JsonFactory;
import org.apache.flink.util.FlinkException;
import org.apache.flink.util.Preconditions;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.core.JsonGenerator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.Executor;
/**
* Abstract request handler for querying aggregated metrics. Subclasses return either a list of all available metrics
* or the aggregated values of them across all/selected entities.
*
* If the query parameters do not contain a "get" parameter the list of all metrics is returned.
* {@code [ { "id" : "X" } ] }
*
*
If the query parameters do contain a "get" parameter, a comma-separated list of metric names is expected as a value.
* {@code /metrics?get=X,Y}
* The handler will then return a list containing the values of the requested metrics.
* {@code [ { "id" : "X", "value" : "S" }, { "id" : "Y", "value" : "T" } ] }
*
*
The "agg" query parameter is used to define which aggregates should be calculated. Available aggregations are
* "sum", "max", "min" and "avg". If the parameter is not specified, all aggregations will be returned.
* {@code /metrics?get=X,Y&agg=min,max}
* The handler will then return a list of objects containing the aggregations for the requested metrics.
* {@code [ { "id" : "X", "min", "1", "max", "2" }, { "id" : "Y", "min", "4", "max", "10"}]}
*/
abstract class AbstractAggregatingMetricsHandler extends AbstractJsonRequestHandler {
protected final Logger log = LoggerFactory.getLogger(getClass());
private static final String PARAMETER_AGGREGATION = "agg";
private final MetricFetcher fetcher;
AbstractAggregatingMetricsHandler(Executor executor, MetricFetcher fetcher) {
super(executor);
this.fetcher = Preconditions.checkNotNull(fetcher);
}
protected abstract Collection getStores(MetricStore store, Map pathParameters, Map queryParameters);
@Override
public CompletableFuture handleJsonRequest(Map pathParams, Map queryParams, JobManagerGateway jobManagerGateway) {
return CompletableFuture.supplyAsync(
() -> {
try {
fetcher.update();
String requestedMetricsList = queryParams.get(AbstractMetricsHandler.PARAMETER_METRICS);
String aggTypeList = queryParams.get(PARAMETER_AGGREGATION);
MetricStore store = fetcher.getMetricStore();
Collection stores = getStores(store, pathParams, queryParams);
if (stores == null){
return "[]";
}
if (requestedMetricsList == null) {
Collection list = getAvailableMetrics(stores);
return mapMetricListToJson(list);
}
if (requestedMetricsList.isEmpty()) {
/*
* The WebInterface doesn't check whether the list of available metrics was empty. This can lead to a
* request for which the "get" parameter is an empty string.
*/
return "[]";
}
String[] requestedMetrics = requestedMetricsList.split(",");
List> requestedAggregationsFactories = new ArrayList<>();
// by default we return all aggregations
if (aggTypeList == null || aggTypeList.isEmpty()) {
requestedAggregationsFactories.add(DoubleAccumulator.DoubleMinimumFactory.get());
requestedAggregationsFactories.add(DoubleAccumulator.DoubleMaximumFactory.get());
requestedAggregationsFactories.add(DoubleAccumulator.DoubleSumFactory.get());
requestedAggregationsFactories.add(DoubleAccumulator.DoubleAverageFactory.get());
} else {
for (String aggregation : aggTypeList.split(",")) {
switch (aggregation.toLowerCase()) {
case DoubleAccumulator.DoubleMinimum.NAME:
requestedAggregationsFactories.add(DoubleAccumulator.DoubleMinimumFactory.get());
break;
case DoubleAccumulator.DoubleMaximum.NAME:
requestedAggregationsFactories.add(DoubleAccumulator.DoubleMaximumFactory.get());
break;
case DoubleAccumulator.DoubleSum.NAME:
requestedAggregationsFactories.add(DoubleAccumulator.DoubleSumFactory.get());
break;
case DoubleAccumulator.DoubleAverage.NAME:
requestedAggregationsFactories.add(DoubleAccumulator.DoubleAverageFactory.get());
break;
default:
log.warn("Invalid aggregation specified: {}", aggregation.toLowerCase());
}
}
}
return getAggregatedMetricValues(stores, requestedMetrics, requestedAggregationsFactories);
} catch (Exception e) {
throw new CompletionException(new FlinkException("Could not retrieve metrics.", e));
}
},
executor);
}
/**
* Returns a JSON string containing a list of all available metrics in the given stores. Effectively this method maps
* the union of all key-sets to JSON.
*
* @param stores metrics
* @return JSON string containing a list of all available metrics
*/
private static Collection getAvailableMetrics(Collection stores) {
Set uniqueMetrics = new HashSet<>();
for (MetricStore.ComponentMetricStore store : stores) {
uniqueMetrics.addAll(store.metrics.keySet());
}
return uniqueMetrics;
}
private static String mapMetricListToJson(Collection metrics) throws IOException {
StringWriter writer = new StringWriter();
JsonGenerator gen = JsonFactory.JACKSON_FACTORY.createGenerator(writer);
gen.writeStartArray();
for (String m : metrics) {
gen.writeStartObject();
gen.writeStringField("id", m);
gen.writeEndObject();
}
gen.writeEndArray();
gen.close();
return writer.toString();
}
/**
* Extracts and aggregates all requested metrics from the given metric stores, and maps the result to a JSON string.
*
* @param stores available metrics
* @param requestedMetrics ids of requested metrics
* @param requestedAggregationsFactories requested aggregations
* @return JSON string containing the requested metrics
* @throws IOException
*/
private String getAggregatedMetricValues(
Collection stores,
String[] requestedMetrics,
List> requestedAggregationsFactories) throws IOException {
StringWriter writer = new StringWriter();
JsonGenerator gen = JsonFactory.JACKSON_FACTORY.createGenerator(writer);
gen.writeStartArray();
for (String requestedMetric : requestedMetrics) {
final Collection values = new ArrayList<>();
try {
for (MetricStore.ComponentMetricStore store : stores) {
String stringValue = store.metrics.get(requestedMetric);
if (stringValue != null) {
values.add(Double.valueOf(stringValue));
}
}
} catch (NumberFormatException nfe) {
log.warn("The metric {} is not numeric and can't be aggregated.", requestedMetric, nfe);
// metric is not numeric so we can't perform aggregations => ignore it
continue;
}
if (!values.isEmpty()) {
gen.writeStartObject();
gen.writeStringField("id", requestedMetric);
for (DoubleAccumulator.DoubleAccumulatorFactory accFactory : requestedAggregationsFactories) {
Iterator valuesIterator = values.iterator();
DoubleAccumulator acc = accFactory.get(valuesIterator.next());
valuesIterator.forEachRemaining(acc::add);
gen.writeStringField(acc.getName(), String.valueOf(acc.getValue()));
}
gen.writeEndObject();
}
}
gen.writeEndArray();
gen.close();
return writer.toString();
}
}