zentol 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_r353664553
########## 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: I'm wondering whether this is a good representation. Having the subtask index encoded in the metric name is a bit redundant, particularly so when thinking about the future where additional watermark metrics may be listed (output watermark, watermarks for 2 input operators) Ideally it would just be an array of `{ currentInputWatermark : XXX }` where the subtaks index is just the index in the array, but since we can't guarantee that metrics for all subtasks are available we could instead opt for `{ subtaskIndex: YYY, currentInputWatermark : XXX }` ---------------------------------------------------------------- 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
