mxm commented on a change in pull request #10238: [FLINK-8949] Add dedicated watermarks metric retrieval endpoint URL: https://github.com/apache/flink/pull/10238#discussion_r353824578
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/rest/handler/job/metrics/JobVertexWatermarksHandler.java ########## @@ -0,0 +1,99 @@ +/* + * 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.JobID; +import org.apache.flink.api.common.time.Time; +import org.apache.flink.runtime.executiongraph.AccessExecutionJobVertex; +import org.apache.flink.runtime.executiongraph.AccessExecutionVertex; +import org.apache.flink.runtime.jobgraph.JobVertexID; +import org.apache.flink.runtime.metrics.MetricNames; +import org.apache.flink.runtime.rest.handler.HandlerRequest; +import org.apache.flink.runtime.rest.handler.RestHandlerException; +import org.apache.flink.runtime.rest.handler.job.AbstractJobVertexHandler; +import org.apache.flink.runtime.rest.handler.legacy.ExecutionGraphCache; +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.JobIDPathParameter; +import org.apache.flink.runtime.rest.messages.JobVertexMessageParameters; +import org.apache.flink.runtime.rest.messages.job.metrics.JobVertexWatermarksHeaders; +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.webmonitor.RestfulGateway; +import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.concurrent.Executor; + + +/** + * Handler that returns the watermarks given a {@link JobID} and {@link JobVertexID}. + */ +public class JobVertexWatermarksHandler extends AbstractJobVertexHandler<MetricCollectionResponseBody, JobVertexMessageParameters> { + + private final MetricFetcher metricFetcher; + + public JobVertexWatermarksHandler( + GatewayRetriever<? extends RestfulGateway> leaderRetriever, + Time timeout, + Map<String, String> responseHeaders, + MetricFetcher metricFetcher, + ExecutionGraphCache executionGraphCache, + Executor executor) { + super(leaderRetriever, + timeout, + responseHeaders, + JobVertexWatermarksHeaders.INSTANCE, + executionGraphCache, + executor); + this.metricFetcher = metricFetcher; + } + + @Override + protected MetricCollectionResponseBody handleRequest( + HandlerRequest<EmptyRequestBody, JobVertexMessageParameters> request, + AccessExecutionJobVertex jobVertex) throws RestHandlerException { + + String jobID = request.getPathParameter(JobIDPathParameter.class).toString(); + String taskID = jobVertex.getJobVertexId().toString(); + + metricFetcher.update(); + MetricStore.TaskMetricStore taskMetricStore = metricFetcher.getMetricStore().getTaskMetricStore(jobID, taskID); + if (taskMetricStore == null) { + return new MetricCollectionResponseBody(Collections.emptyList()); + } + + AccessExecutionVertex[] taskVertices = jobVertex.getTaskVertices(); + List<Metric> metrics = new ArrayList<>(taskVertices.length); + + for (AccessExecutionVertex taskVertex : taskVertices) { + String id = taskVertex.getParallelSubtaskIndex() + "." + MetricNames.IO_CURRENT_INPUT_WATERMARK; + String watermarkValue = taskMetricStore.getMetric(id); + if (watermarkValue != null) { + metrics.add(new Metric(id, watermarkValue)); + } + } + + return new MetricCollectionResponseBody(metrics); Review comment: At this point I think it would be premature optimization. It is more important to fix this, then to save a few bytes for the responses. We already save a good portion of the transferred bytes due to the new zero byte header. I'd rather make a breaking change for the next release (if really necessary), instead of leaving this broken. There is also another good argument for keeping this representation: The response format is aligned with the general metrics response which keeps a consistent and easy to understand metrics format. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
