Github user kl0u commented on a diff in the pull request:
https://github.com/apache/flink/pull/4901#discussion_r147697678
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/rest/handler/legacy/metrics/AggregatingSubtasksMetricsHandler.java
---
@@ -0,0 +1,117 @@
+/*
+ * 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.flink.runtime.rest.handler.legacy.metrics;
+
+import org.apache.flink.util.UnionIterator;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.concurrent.Executor;
+
+import static
org.apache.flink.runtime.rest.handler.legacy.metrics.JobMetricsHandler.PARAMETER_JOB_ID;
+import static
org.apache.flink.runtime.rest.handler.legacy.metrics.JobVertexMetricsHandler.PARAMETER_VERTEX_ID;
+
+/**
+ * Request handler that returns, aggregated across all subtasks, a list of
all available metrics or the values
+ * for a set of metrics.
+ *
+ * <p>Specific subtasks can be selected for aggregation by specifying a
comma-separated list of integer ranges.
+ * {@code /metrics?get=X,Y&subtasks=0-2,4-5}
+ */
+public class AggregatingSubtasksMetricsHandler extends
AbstractAggregatingMetricsHandler {
+ public AggregatingSubtasksMetricsHandler(Executor executor,
MetricFetcher fetcher) {
+ super(executor, fetcher);
+ }
+
+ @Override
+ protected Collection<? extends MetricStore.ComponentMetricStore>
getStores(MetricStore store, Map<String, String> pathParameters, Map<String,
String> queryParameters) {
+ String jobID = pathParameters.get(PARAMETER_JOB_ID);
+ String taskID = pathParameters.get(PARAMETER_VERTEX_ID);
+ if (jobID == null) {
+ return Collections.emptyList();
+ }
+ if (taskID == null) {
+ return Collections.emptyList();
+ }
+ String subtasksList = queryParameters.get("subtasks");
+ if (subtasksList == null || subtasksList.isEmpty()) {
+ return store.getTaskMetricStore(jobID,
taskID).getAllSubtaskMetricStores();
+ } else {
+ Iterable<Integer> subtasks =
getIntegerRangeFromString(subtasksList);
+ Collection<MetricStore.ComponentMetricStore>
subtaskStores = new ArrayList<>();
+ for (int subtask : subtasks) {
+
subtaskStores.add(store.getSubtaskMetricStore(jobID, taskID, subtask));
+ }
+ return subtaskStores;
+ }
+ }
+
+ @Override
+ public String[] getPaths() {
+ return new
String[]{"/jobs/:jobid/vertices/:vertexid/subtasks/metrics"};
+ }
+
+ private Iterable<Integer> getIntegerRangeFromString(String
rangeDefinition) throws NumberFormatException {
+ final String[] ranges = rangeDefinition.trim().split(",");
+
+ UnionIterator<Integer> iterators = new UnionIterator<>();
+
+ for (String rawRange : ranges) {
+ try {
+ Iterator<Integer> rangeIterator;
+ String range = rawRange.trim();
+ int dashIdx = range.indexOf('-');
+ if (dashIdx == -1) {
+ // only one value in range:
+ rangeIterator =
Collections.singleton(Integer.valueOf(range)).iterator();
+ } else {
+ // evaluate range
+ final int start =
Integer.valueOf(range.substring(0, dashIdx));
+ final int end =
Integer.valueOf(range.substring(dashIdx + 1, range.length()));
+ rangeIterator = new Iterator<Integer>()
{
+ int i = start;
+
+ @Override
+ public boolean hasNext() {
+ return i <= end;
+ }
+
+ @Override
+ public Integer next() {
+ return i++;
--- End diff --
Here you should throw a `NoSuchElementException` if the `next()` is called
for an index outside the size of the list (it is part of the iterator contract).
---
