Java tutorial
/** * Copyright 2017 Pivotal Software, Inc. * <p> * Licensed 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 * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * 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 io.micrometer.spring.export.prometheus; import java.net.UnknownHostException; import java.time.Duration; import java.util.Map; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ScheduledFuture; import org.springframework.scheduling.TaskScheduler; import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler; import org.springframework.util.Assert; import org.springframework.util.StringUtils; import io.prometheus.client.CollectorRegistry; import io.prometheus.client.exporter.PushGateway; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * Class that can be used to manage the pushing of metrics to a {@link PushGateway * Prometheus PushGateway}. Handles the scheduling of push operations, error handling and * shutdown operations. * * @author David J. M. Karlsen * @author Phillip Webb * @since 1.1.0 */ public class PrometheusPushGatewayManager { private static final Log logger = LogFactory.getLog(PrometheusPushGatewayManager.class); private final PushGateway pushGateway; private final CollectorRegistry registry; private final String job; private final Map<String, String> groupingKey; private final ShutdownOperation shutdownOperation; private final TaskScheduler scheduler; private ScheduledFuture<?> scheduled; /** * Create a new {@link PrometheusPushGatewayManager} instance using a single threaded * {@link TaskScheduler}. * @param pushGateway the source push gateway * @param registry the collector registry to push * @param pushRate the rate at which push operations occur * @param job the job ID for the operation * @param groupingKey an optional set of grouping keys for the operation * @param shutdownOperation the shutdown operation that should be performed when * context is closed. */ public PrometheusPushGatewayManager(PushGateway pushGateway, CollectorRegistry registry, Duration pushRate, String job, Map<String, String> groupingKey, ShutdownOperation shutdownOperation) { this(pushGateway, registry, new PushGatewayTaskScheduler(), pushRate, job, groupingKey, shutdownOperation); } /** * Create a new {@link PrometheusPushGatewayManager} instance. * @param pushGateway the source push gateway * @param registry the collector registry to push * @param scheduler the scheduler used for operations * @param pushRate the rate at which push operations occur * @param job the job ID for the operation * @param groupingKey an optional set of grouping keys for the operation * @param shutdownOperation the shutdown operation that should be performed when * context is closed. */ public PrometheusPushGatewayManager(PushGateway pushGateway, CollectorRegistry registry, TaskScheduler scheduler, Duration pushRate, String job, Map<String, String> groupingKey, ShutdownOperation shutdownOperation) { Assert.notNull(pushGateway, "PushGateway must not be null"); Assert.notNull(registry, "Registry must not be null"); Assert.notNull(scheduler, "Scheduler must not be null"); Assert.notNull(pushRate, "PushRate must not be null"); Assert.hasLength(job, "Job must not be empty"); this.pushGateway = pushGateway; this.registry = registry; this.job = job; this.groupingKey = groupingKey; this.shutdownOperation = (shutdownOperation != null) ? shutdownOperation : ShutdownOperation.NONE; this.scheduler = scheduler; this.scheduled = this.scheduler.scheduleAtFixedRate(this::push, pushRate.toMillis()); } private void push() { try { this.pushGateway.pushAdd(this.registry, this.job, this.groupingKey); } catch (UnknownHostException ex) { String host = ex.getMessage(); String message = "Unable to locate prometheus push gateway host" + (StringUtils.hasLength(host) ? " '" + host + "'" : "") + ". No longer attempting metrics publication to this host"; logger.error(message, ex); shutdown(ShutdownOperation.NONE); } catch (Throwable ex) { logger.error("Unable to push metrics to Prometheus Pushgateway", ex); } } private void delete() { try { this.pushGateway.delete(this.job, this.groupingKey); } catch (Throwable ex) { logger.error("Unable to delete metrics from Prometheus Pushgateway", ex); } } /** * Shutdown the manager, running any {@link ShutdownOperation}. */ public void shutdown() { shutdown(this.shutdownOperation); } private void shutdown(ShutdownOperation shutdownOperation) { if (this.scheduler instanceof PushGatewayTaskScheduler) { ((PushGatewayTaskScheduler) this.scheduler).shutdown(); } this.scheduled.cancel(false); switch (shutdownOperation) { case PUSH: push(); break; case DELETE: delete(); break; } } /** * The operation that should be performed on shutdown. */ public enum ShutdownOperation { /** * Don't perform any shutdown operation. */ NONE, /** * Perform a 'push' before shutdown. */ PUSH, /** * Perform a 'delete' before shutdown. */ DELETE } /** * {@link TaskScheduler} used when the user doesn't specify one. */ static class PushGatewayTaskScheduler extends ThreadPoolTaskScheduler { PushGatewayTaskScheduler() { setPoolSize(1); setDaemon(true); setThreadGroupName("prometheus-push-gateway"); } @Override public ScheduledExecutorService getScheduledExecutor() throws IllegalStateException { return Executors.newSingleThreadScheduledExecutor(this::newThread); } } }