storm-client/src/jvm/org/apache/storm/metric/LoggingMetricsConsumer.java

/**
 * 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.storm.metric;

import java.util.Collection;
import java.util.Map;
import org.apache.storm.metric.api.IMetricsConsumer;
import org.apache.storm.task.IErrorReporter;
import org.apache.storm.task.TopologyContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Listens for all metrics, dumps them to log
 *
 * <p>To use, add this to your topology's configuration:
 *
 * <p>```java conf.registerMetricsConsumer(org.apache.storm.metrics.LoggingMetricsConsumer.class, 1); ```
 *
 * <p>Or edit the storm.yaml config file:
 *
 * <p>```yaml topology.metrics.consumer.register: - class: "org.apache.storm.metrics.LoggingMetricsConsumer" parallelism.hint: 1 ```
 */
public class LoggingMetricsConsumer implements IMetricsConsumer {
    public static final Logger LOG = LoggerFactory.getLogger(LoggingMetricsConsumer.class);
    private static String padding = "                       ";

    @Override
    public void prepare(Map<String, Object> topoConf, Object registrationArgument, TopologyContext context, IErrorReporter errorReporter) {
    }

    @Override
    public void handleDataPoints(TaskInfo taskInfo, Collection<DataPoint> dataPoints) {
        StringBuilder sb = new StringBuilder();
        String header = String.format("%d\t%15s:%-4d\t%3d:%-11s\t",
                                      taskInfo.timestamp,
                                      taskInfo.srcWorkerHost, taskInfo.srcWorkerPort,
                                      taskInfo.srcTaskId,
                                      taskInfo.srcComponentId);
        sb.append(header);
        for (DataPoint p : dataPoints) {
            sb.delete(header.length(), sb.length());
            sb.append(p.name)
                    .append(padding)
                    .delete(header.length() + 23, sb.length())
                    .append("\t")
                    .append(p.value);
            LOG.info(sb.toString());
        }
    }

    @Override
    public void cleanup() {
    }
}