Github user GJL commented on a diff in the pull request:
https://github.com/apache/flink/pull/5055#discussion_r152804507
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/rest/handler/job/metrics/AbstractMetricsHandler.java
---
@@ -0,0 +1,141 @@
+/*
+ * 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.job.metrics;
+
+import org.apache.flink.api.common.time.Time;
+import org.apache.flink.runtime.dispatcher.DispatcherGateway;
+import org.apache.flink.runtime.rest.handler.AbstractRestHandler;
+import org.apache.flink.runtime.rest.handler.HandlerRequest;
+import org.apache.flink.runtime.rest.handler.RestHandlerException;
+import org.apache.flink.runtime.rest.handler.legacy.metrics.MetricFetcher;
+import org.apache.flink.runtime.rest.handler.legacy.metrics.MetricStore;
+import org.apache.flink.runtime.rest.messages.EmptyRequestBody;
+import org.apache.flink.runtime.rest.messages.MessageHeaders;
+import org.apache.flink.runtime.rest.messages.MessageParameters;
+import org.apache.flink.runtime.rest.messages.job.metrics.Metric;
+import
org.apache.flink.runtime.rest.messages.job.metrics.MetricCollectionResponseBody;
+import
org.apache.flink.runtime.rest.messages.job.metrics.MetricsFilterParameter;
+import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever;
+
+import
org.apache.flink.shaded.netty4.io.netty.handler.codec.http.HttpResponseStatus;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * Request handler that returns for a given task a list of all available
metrics or the values for a set of metrics.
+ *
+ * <p>If the query parameters do not contain a "get" parameter the list of
all metrics is returned.
+ * {@code {"available": [ { "name" : "X", "id" : "X" } ] } }
+ *
+ * <p>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" } ]
}
+ *
+ * @param <M> Type of the concrete MessageParameters
+ */
+public abstract class AbstractMetricsHandler<M extends MessageParameters>
extends
+ AbstractRestHandler<DispatcherGateway, EmptyRequestBody,
MetricCollectionResponseBody, M> {
+
+ private final MetricFetcher metricFetcher;
+
+ public AbstractMetricsHandler(
+ CompletableFuture<String> localRestAddress,
+ GatewayRetriever<DispatcherGateway> leaderRetriever,
+ Time timeout,
+ Map<String, String> headers,
+ MessageHeaders<EmptyRequestBody,
MetricCollectionResponseBody, M> messageHeaders,
+ MetricFetcher metricFetcher) {
+ super(localRestAddress, leaderRetriever, timeout, headers,
messageHeaders);
+ this.metricFetcher = requireNonNull(metricFetcher,
"metricFetcher must not be null");
+ }
+
+ @Override
+ protected CompletableFuture<MetricCollectionResponseBody> handleRequest(
+ @Nonnull HandlerRequest<EmptyRequestBody, M> request,
+ @Nonnull DispatcherGateway gateway) throws
RestHandlerException {
+ metricFetcher.update();
+
+ final MetricStore.ComponentMetricStore componentMetricStore =
getComponentMetricStore(
+ request,
+ metricFetcher.getMetricStore());
+
+ if (componentMetricStore == null ||
componentMetricStore.metrics == null) {
+ return CompletableFuture.completedFuture(
+ new
MetricCollectionResponseBody(Collections.emptyList()));
+ }
+
+ final Set<String> requestedMetrics = new
HashSet<>(request.getQueryParameter(
+ MetricsFilterParameter.class));
+
+ if (requestedMetrics.isEmpty()) {
+ return CompletableFuture.completedFuture(
+ new
MetricCollectionResponseBody(getAvailableMetrics(componentMetricStore)));
+ } else {
+ final List<Metric> metrics =
getRequestedMetrics(componentMetricStore, requestedMetrics);
+ return CompletableFuture.completedFuture(new
MetricCollectionResponseBody(metrics));
+ }
+ }
+
+ /**
+ * Returns the {@link MetricStore.ComponentMetricStore} that should be
queried for metrics.
+ */
+ @Nullable
+ protected abstract MetricStore.ComponentMetricStore
getComponentMetricStore(
+ HandlerRequest<EmptyRequestBody, M> request,
+ MetricStore metricStore);
+
+ private static List<Metric>
getAvailableMetrics(MetricStore.ComponentMetricStore componentMetricStore) {
+ return componentMetricStore.metrics
+ .keySet()
+ .stream()
+ .map(Metric::new)
+ .collect(Collectors.toList());
+ }
+
+ private static List<Metric> getRequestedMetrics(
+ MetricStore.ComponentMetricStore componentMetricStore,
+ Set<String> requestedMetrics) throws
RestHandlerException {
+
+ final List<Metric> metrics = new
ArrayList<>(requestedMetrics.size());
+ for (final String requestedMetric : requestedMetrics) {
+ final String value =
componentMetricStore.getMetric(requestedMetric, null);
--- End diff --
If `requestedMetric` is an empty string, we will return HTTP code 404. This
is different compared to the legacy handler. If this is a problem, I can change
it to the old behavior.
---
