features/src/main/java/org/apache/karaf/cellar/features/FeaturesEventHandler.java

/*
 * 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 org.apache.karaf.cellar.features;

import org.apache.karaf.cellar.core.Configurations;
import org.apache.karaf.cellar.core.control.BasicSwitch;
import org.apache.karaf.cellar.core.control.Switch;
import org.apache.karaf.cellar.core.control.SwitchStatus;
import org.apache.karaf.cellar.core.event.EventHandler;
import org.apache.karaf.cellar.core.event.EventType;
import org.apache.karaf.features.FeatureEvent;
import org.apache.karaf.features.FeaturesService;
import org.osgi.service.cm.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.EnumSet;

/**
 * Handler for cluster features event.
 */
public class FeaturesEventHandler extends FeaturesSupport implements EventHandler<ClusterFeaturesEvent> {

    private static final transient Logger LOGGER = LoggerFactory.getLogger(FeaturesSynchronizer.class);

    public static final String SWITCH_ID = "org.apache.karaf.cellar.event.features.handler";

    private final Switch eventSwitch = new BasicSwitch(SWITCH_ID);

    @Override
    public void init() {
        super.init();
    }

    @Override
    public void destroy() {
        super.destroy();
    }

    /**
     * Handle a received cluster features event.
     *
     * @param event the received cluster feature event.
     */
    public void handle(ClusterFeaturesEvent event) {

        if (this.getSwitch().getStatus().equals(SwitchStatus.OFF)) {
            LOGGER.debug("CELLAR FEATURE: {} switch is OFF, cluster event is not handled", SWITCH_ID);
            return;
        }

        if (groupManager == null) {
        	//in rare cases for example right after installation this happens!
        	LOGGER.error("CELLAR FEATURE: retrieved event {} while groupManager is not available yet!", event);
        	return;
        }

        // check if the group is local
        if (!groupManager.isLocalGroup(event.getSourceGroup().getName())) {
            LOGGER.debug("CELLAR FEATURE: node is not part of the event cluster group {}", event.getSourceGroup().getName());
            return;
        }

        // check if it's not a "local" event
        if (event.getSourceNode() != null && event.getSourceNode().getId().equalsIgnoreCase(clusterManager.getNode().getId())) {
            LOGGER.trace("CELLAR FEATURE: cluster event is local (coming from local synchronizer or listener)");
            return;
        }

        String name = event.getName();
        String version = event.getVersion();
        if (isAllowed(event.getSourceGroup(), Constants.CATEGORY, name, EventType.INBOUND) || event.getForce()) {
            FeatureEvent.EventType type = event.getType();
            Boolean isInstalled = isFeatureInstalledLocally(name, version);
            try {
                if (FeatureEvent.EventType.FeatureInstalled.equals(type) && !isInstalled) {
                    boolean noRefresh = event.getNoRefresh();
                    boolean noStart = event.getNoStart();
                    EnumSet<FeaturesService.Option> options = EnumSet.noneOf(FeaturesService.Option.class);
                    if (noRefresh) {
                        options.add(FeaturesService.Option.NoAutoRefreshBundles);
                    }
                    if (noStart) {
                        options.add(FeaturesService.Option.NoAutoStartBundles);
                    }
                    if (version != null) {
                        LOGGER.debug("CELLAR FEATURE: installing feature {}/{}", name, version);
                        featuresService.installFeature(name, version, options);
                    } else {
                        LOGGER.debug("CELLAR FEATURE: installing feature {}", name);
                        featuresService.installFeature(name, options);
                    }
                } else if (FeatureEvent.EventType.FeatureUninstalled.equals(type) && isInstalled) {
                    boolean noRefresh = event.getNoRefresh();
                    EnumSet<FeaturesService.Option> options = EnumSet.noneOf(FeaturesService.Option.class);
                    if (noRefresh) {
                        options.add(FeaturesService.Option.NoAutoRefreshBundles);
                    }
                    if (version != null) {
                        LOGGER.debug("CELLAR FEATURE: uninstalling feature {}/{}", name, version);
                        featuresService.uninstallFeature(name, version, options);
                    } else {
                        LOGGER.debug("CELLAR FEATURE: uninstalling feature {}", name);
                        featuresService.uninstallFeature(name, options);
                    }
                }
            } catch (Exception e) {
                LOGGER.error("CELLAR FEATURE: failed to handle cluster feature event", e);
            }
        } else LOGGER.trace("CELLAR FEATURE: feature {} is marked BLOCKED INBOUND for cluster group {}", name, event.getSourceGroup().getName());
    }

    /**
     * Get the event type that this handler is able to handle.
     *
     * @return the cluster features event type.
     */
    @Override
    public Class<ClusterFeaturesEvent> getType() {
        return ClusterFeaturesEvent.class;
    }

    /**
     * Get the handler switch.
     *
     * @return the handler switch.
     */
    @Override
    public Switch getSwitch() {
        // load the switch status from the config
        try {
            Configuration configuration = configurationAdmin.getConfiguration(Configurations.NODE, null);
            if (configuration != null) {
                Boolean status = new Boolean((String) configuration.getProperties().get(Configurations.HANDLER + "." + this.getClass().getName()));
                if (status) {
                    eventSwitch.turnOn();
                } else {
                    eventSwitch.turnOff();
                }
            }
        } catch (Exception e) {
            // ignore
        }
        return eventSwitch;
    }

}