org.apache.whirr.service.cassandra.CassandraClusterActionHandler.java Source code

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Here is the source code for org.apache.whirr.service.cassandra.CassandraClusterActionHandler.java

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/**
 * 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.whirr.service.cassandra;

import static org.apache.whirr.RolePredicates.role;
import static org.apache.whirr.service.FirewallManager.Rule;
import static org.jclouds.scriptbuilder.domain.Statements.call;

import org.apache.whirr.ClusterSpec;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.collect.Lists;

import java.io.IOException;
import java.math.BigInteger;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.apache.commons.configuration.Configuration;
import org.apache.whirr.Cluster;
import org.apache.whirr.Cluster.Instance;
import org.apache.whirr.service.ClusterActionEvent;
import org.apache.whirr.service.ClusterActionHandlerSupport;
import org.apache.whirr.service.jclouds.StatementBuilder;

public class CassandraClusterActionHandler extends ClusterActionHandlerSupport {

    public static final String CASSANDRA_ROLE = "cassandra";
    public static final int CLIENT_PORT = 9160;
    public static final int JMX_PORT = 7199;

    public static final String BIN_TARBALL = "whirr.cassandra.tarball.url";
    public static final String MAJOR_VERSION = "whirr.cassandra.version.major";

    @Override
    public String getRole() {
        return CASSANDRA_ROLE;
    }

    @Override
    protected void beforeBootstrap(ClusterActionEvent event) throws IOException {
        ClusterSpec clusterSpec = event.getClusterSpec();
        Configuration conf = clusterSpec.getConfiguration();

        addStatement(event, call(getInstallFunction(conf, "java", "install_openjdk")));
        addStatement(event, call("install_tarball"));

        addStatement(event, call("install_service"));
        addStatement(event, call("remove_service"));

        Configuration config = clusterSpec.getConfiguration();

        String tarball = prepareRemoteFileUrl(event, config.getString(BIN_TARBALL, null));
        String major = config.getString(MAJOR_VERSION, null);

        if (tarball != null && major != null) {
            addStatement(event, call("install_cassandra", major, tarball));
        } else {
            addStatement(event, call("install_cassandra"));
        }
    }

    @Override
    protected void beforeConfigure(final ClusterActionEvent event) throws IOException, InterruptedException {
        Cluster cluster = event.getCluster();
        Set<Instance> instances = cluster.getInstancesMatching(role(CASSANDRA_ROLE));

        event.getFirewallManager().addRule(Rule.create().destination(instances).ports(CLIENT_PORT, JMX_PORT));

        setInitialTokensAsEnvironmentVariables(event, instances);

        List<Instance> seeds = getSeeds(instances);
        String seedServers = Joiner.on(' ').join(getPrivateIps(seeds));

        addStatement(event, call("configure_cassandra", seedServers));
    }

    @Override
    protected void beforeStart(ClusterActionEvent event) {
        addStatement(event, call("start_cassandra"));
    }

    @Override
    protected void beforeStop(ClusterActionEvent event) {
        addStatement(event, call("stop_cassandra"));
    }

    @Override
    protected void beforeCleanup(ClusterActionEvent event) {
        addStatement(event, call("remove_service"));
        addStatement(event, call("cleanup_cassandra"));
    }

    private List<String> getPrivateIps(List<Instance> instances) {
        return Lists.transform(Lists.newArrayList(instances), new Function<Instance, String>() {
            @Override
            public String apply(Instance instance) {
                return instance.getPrivateIp();
            }
        });
    }

    /**
     * Pick a selection of the nodes that are to become seeds. TODO improve
     * selection method. Right now it picks 20% of the nodes as seeds, or a
     * minimum of one node if it is a small cluster.
     *
     * @param instances all nodes in cluster
     * @return list of seeds
     */
    protected List<Instance> getSeeds(Set<Instance> instances) {
        List<Instance> nodes = Lists.newArrayList(instances);
        int seeds = (int) Math.ceil(Math.max(1, instances.size() * 0.2));
        List<Instance> rv = Lists.newArrayList();
        for (int i = 0; i < seeds; i++) {
            rv.add(nodes.get(i));
        }
        return rv;
    }

    /**
     * Compute initial_token for a balanced cluster
     */
    protected List<String> computeInitialTokens(int numberOfNodes) {
        List<String> tokens = Lists.newArrayList();

        BigInteger step = new BigInteger("2").pow(127).divide(BigInteger.valueOf(numberOfNodes));

        for (int i = 0; i < numberOfNodes; i++) {
            tokens.add(step.multiply(BigInteger.valueOf(i)).toString());
        }

        return tokens;
    }

    private void setInitialTokensAsEnvironmentVariables(ClusterActionEvent event, Set<Instance> instances) {
        List<String> tokens = computeInitialTokens(instances.size());

        StatementBuilder statementBuilder = event.getStatementBuilder();
        Iterator it = tokens.iterator();

        for (Instance instance : instances) {
            statementBuilder.addExportPerInstance(instance.getId(), "cassandraInitialToken", (String) it.next());
        }
    }
}