node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/OperatorChangeApplicationMaintainer.java


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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.maintenance;

import com.yahoo.config.provision.ApplicationId;
import com.yahoo.config.provision.Deployer;
import com.yahoo.vespa.hosted.provision.Node;
import com.yahoo.vespa.hosted.provision.NodeRepository;
import com.yahoo.vespa.hosted.provision.node.Agent;

import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import java.util.List;
import java.util.stream.Collectors;

/**
 * The application maintainer detects manual operator changes to nodes and redeploys affected applications.
 * The purpose of this is to redeploy affected applications faster than achieved by the regular application
 * maintenance to reduce the time period where the node repository and the application model is out of sync.
 * 
 * Why can't the manual change directly make the application redeployment?
 * Because the redeployment must run at the right config server, while the node state change may be running
 * at any config server.
 *
 * @author bratseth
 */
public class OperatorChangeApplicationMaintainer extends ApplicationMaintainer {

    private final Clock clock;
    
    private Instant previousRun;
    
    public OperatorChangeApplicationMaintainer(Deployer deployer, NodeRepository nodeRepository, Clock clock,
                                               Duration interval, JobControl jobControl) {
        super(deployer, nodeRepository, interval, jobControl);
        this.clock = clock;
        previousRun = clock.instant(); // Changes before this will be caught by the first PeriodicApplicationMaintainer run
    }

    @Override
    protected List<Node> nodesNeedingMaintenance() {
        Instant windowEnd = clock.instant();
        Instant windowStart = previousRun;
        previousRun = windowEnd;
        return nodeRepository().getNodes().stream()
                               .filter(node -> node.allocation().isPresent())
                               .filter(node -> hasManualStateChangeSince(windowStart, node))
                               .collect(Collectors.toList());
    }
    
    private boolean hasManualStateChangeSince(Instant instant, Node node) {
        return node.history().events().stream()
                .anyMatch(event -> event.agent() == Agent.operator && event.at().isAfter(instant));
    }

    /** 
     * Deploy in the maintenance thread to avoid scheduling multiple deployments of the same application if it takes
     * longer to deploy than the (short) maintenance interval of this
     */
    @Override
    protected void deploy(ApplicationId application) {
        deployWithLock(application);
        log.info("Redeployed application " + application.toShortString() +
                 " as a manual change was made to its nodes");
    }

}