Github user kl0u commented on a diff in the pull request:
https://github.com/apache/flink/pull/4901#discussion_r147653983
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/rest/handler/legacy/metrics/AggregatingSubtasksMetricsHandler.java
---
@@ -0,0 +1,70 @@
+/*
+ * 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 java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+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.
+ */
+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);
--- End diff --
What happens here if `jobID == null`?
---
