cameronlee314 commented on a change in pull request #1495: URL: https://github.com/apache/samza/pull/1495#discussion_r627011501
########## File path: samza-core/src/main/java/org/apache/samza/metrics/reporter/LoggingMetricsReporter.java ########## @@ -0,0 +1,132 @@ +/* + * 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.samza.metrics.reporter; + +import java.util.Map; +import java.util.Queue; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.regex.Pattern; +import com.google.common.annotations.VisibleForTesting; +import org.apache.samza.metrics.Counter; +import org.apache.samza.metrics.Gauge; +import org.apache.samza.metrics.Metric; +import org.apache.samza.metrics.MetricsReporter; +import org.apache.samza.metrics.MetricsVisitor; +import org.apache.samza.metrics.ReadableMetricsRegistry; +import org.apache.samza.metrics.Timer; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Implementation of {@link MetricsReporter} which logs metrics which match a regex. + * The regex is checked against "[source name]-[group name]-[metric name]". + */ +public class LoggingMetricsReporter implements MetricsReporter { + private static final Logger LOG = LoggerFactory.getLogger(LoggingMetricsReporter.class); + /** + * First part is source, second part is group name, third part is metric name + */ + private static final String FULL_METRIC_FORMAT = "%s-%s-%s"; + + private final ScheduledExecutorService scheduledExecutorService; + private final Pattern metricsToLog; + private final long loggingIntervalSeconds; + private final Queue<Runnable> loggingTasks = new ConcurrentLinkedQueue<>(); + + /** + * @param scheduledExecutorService executes the logging tasks + * @param metricsToLog Only log the metrics which match this regex. The strings for matching against this metric are + * constructed by concatenating source name, group name, and metric name, delimited by dashes. + * @param loggingIntervalSeconds interval at which to log metrics + */ + public LoggingMetricsReporter(ScheduledExecutorService scheduledExecutorService, Pattern metricsToLog, + long loggingIntervalSeconds) { + this.scheduledExecutorService = scheduledExecutorService; + this.metricsToLog = metricsToLog; + this.loggingIntervalSeconds = loggingIntervalSeconds; + } + + @Override + public void start() { + this.scheduledExecutorService.scheduleAtFixedRate(() -> this.loggingTasks.forEach(Runnable::run), + this.loggingIntervalSeconds, this.loggingIntervalSeconds, TimeUnit.SECONDS); + } + + @Override + public void register(String source, ReadableMetricsRegistry registry) { + this.loggingTasks.add(buildLoggingTask(source, registry)); + } + + @Override + public void stop() { + this.scheduledExecutorService.shutdown(); + try { + this.scheduledExecutorService.awaitTermination(10, TimeUnit.SECONDS); + } catch (InterruptedException e) { + LOG.warn("Interrupted while shutting down executor", e); + } + if (!this.scheduledExecutorService.isTerminated()) { + LOG.warn("Unable to shutdown executor"); + } + } + + /** + * VisibleForTesting so that the logging call can be verified in unit tests. + */ + @VisibleForTesting + void doLog(String logString) { + LOG.info(logString); + } + + private Runnable buildLoggingTask(String source, ReadableMetricsRegistry registry) { + return () -> { + for (String group : registry.getGroups()) { + for (Map.Entry<String, Metric> metricGroupEntry : registry.getGroup(group).entrySet()) { + metricGroupEntry.getValue().visit(new MetricsVisitor() { + @Override + public void counter(Counter counter) { + logMetric(source, group, counter.getName(), counter.getCount()); + } + + @Override + public <T> void gauge(Gauge<T> gauge) { + logMetric(source, group, gauge.getName(), gauge.getValue()); + } + + @Override + public void timer(Timer timer) { + logMetric(source, group, timer.getName(), timer.getSnapshot().getAverage()); + } + }); + } + } + }; + } + + private <T> void logMetric(String source, String group, String metricName, T value) { + String fullMetricName = String.format(FULL_METRIC_FORMAT, source, group, metricName); + if (this.metricsToLog.matcher(fullMetricName).matches()) { + doLog(String.format("Metric: %s, Value: %s", fullMetricName, value)); Review comment: I figure that someone could also just grep `LoggingMetricsReporter` anyways, since a tag like `Metric` or `[Metric]` could still catch logs from some other component. -- This is an automated message from the Apache Git Service. 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