Java tutorial
/* * Copyright (c) 2014 Spotify AB. * * 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 * * 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 com.spotify.helios.rollingupdate; import static com.google.common.base.Preconditions.checkNotNull; import com.spotify.helios.common.descriptors.DeploymentGroup; import com.spotify.helios.common.descriptors.HostStatus; import com.spotify.helios.common.descriptors.RolloutTask; import com.google.common.collect.ImmutableList; import com.google.common.collect.Lists; import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class RollingUndeployPlanner implements RolloutPlanner { private final DeploymentGroup deploymentGroup; private RollingUndeployPlanner(final DeploymentGroup deploymentGroup) { this.deploymentGroup = checkNotNull(deploymentGroup, "deploymentGroup"); } public static RollingUndeployPlanner of(final DeploymentGroup deploymentGroup) { return new RollingUndeployPlanner(deploymentGroup); } @Override public List<RolloutTask> plan(final Map<String, HostStatus> hostsAndStatuses) { // we only care about hosts that are UP final List<String> hosts = hostsAndStatuses.entrySet().stream() .filter(entry -> entry.getValue().getStatus().equals(HostStatus.Status.UP)) .map(entry -> entry.getKey()).collect(Collectors.toList()); // generate the rollout tasks final List<RolloutTask> rolloutTasks = Lists.newArrayList(); final int parallelism = deploymentGroup.getRolloutOptions() != null ? deploymentGroup.getRolloutOptions().getParallelism() : 1; Lists.partition(hosts, parallelism).forEach(partition -> rolloutTasks.addAll(rolloutTasks(partition))); return ImmutableList.copyOf(rolloutTasks); } private List<RolloutTask> rolloutTasks(final List<String> hosts) { final ImmutableList.Builder<RolloutTask> tasks = ImmutableList.builder(); hosts.forEach(host -> { tasks.add(RolloutTask.of(RolloutTask.Action.FORCE_UNDEPLOY_JOBS, host)); }); hosts.forEach(host -> { tasks.add(RolloutTask.of(RolloutTask.Action.AWAIT_UNDEPLOYED, host)); tasks.add(RolloutTask.of(RolloutTask.Action.MARK_UNDEPLOYED, host)); }); return tasks.build(); } }