com.netflix.exhibitor.core.state.Checker.java Source code

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Here is the source code for com.netflix.exhibitor.core.state.Checker.java

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/*
 *
 *  Copyright 2011 Netflix, Inc.
 *
 *     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.netflix.exhibitor.core.state;

import com.google.common.collect.Iterables;
import com.netflix.exhibitor.core.Exhibitor;
import com.netflix.exhibitor.core.config.InstanceConfig;
import com.netflix.exhibitor.core.config.StringConfigs;
import com.netflix.exhibitor.core.controlpanel.ControlPanelTypes;
import java.util.List;

/**
 * Determines the state of the ZK server
 */
public class Checker {
    private final Exhibitor exhibitor;
    private final String hostname;

    public Checker(Exhibitor exhibitor) {
        this(exhibitor, "localhost");
    }

    public Checker(Exhibitor exhibitor, String hostname) {
        this.exhibitor = exhibitor;
        this.hostname = hostname;
    }

    public InstanceStateTypes calculateState() throws Exception {
        InstanceConfig config = exhibitor.getConfigManager().getConfig();

        if (!isSet(config, StringConfigs.ZOOKEEPER_DATA_DIRECTORY)
                || !isSet(config, StringConfigs.ZOOKEEPER_INSTALL_DIRECTORY)) {
            return InstanceStateTypes.LATENT;
        }

        InstanceStateTypes potentialState = InstanceStateTypes.DOWN;
        ServerList serverList = new ServerList(config.getString(StringConfigs.SERVERS_SPEC));
        ServerSpec us = Iterables.find(serverList.getSpecs(), ServerList.isUs(exhibitor.getThisJVMHostname()),
                null);
        if (us != null) {
            if (!exhibitor.getControlPanelValues().isSet(ControlPanelTypes.RESTARTS)) {
                potentialState = InstanceStateTypes.NO_RESTARTS_DOWN;
            }
        } else {
            if (!exhibitor.getControlPanelValues().isSet(ControlPanelTypes.UNLISTED_RESTARTS)) {
                potentialState = InstanceStateTypes.UNLISTED_DOWN;
            }
        }

        InstanceStateTypes actualState = potentialState;
        String ruok = new FourLetterWord(FourLetterWord.Word.RUOK, hostname, config,
                exhibitor.getConnectionTimeOutMs()).getResponse();
        if ("imok".equals(ruok)) {
            // The following code depends on inside knowledge of the "srvr" response. If they change it
            // this code might break

            List<String> lines = new FourLetterWord(FourLetterWord.Word.SRVR, hostname, config,
                    exhibitor.getConnectionTimeOutMs()).getResponseLines();
            for (String line : lines) {
                if (line.contains("not currently serving")) {
                    actualState = InstanceStateTypes.NOT_SERVING;
                    break;
                }

                if (line.toLowerCase().startsWith("mode")) {
                    actualState = InstanceStateTypes.SERVING;
                    break;
                }
            }
        }

        return actualState;
    }

    private boolean isSet(InstanceConfig config, StringConfigs type) {
        String s = config.getString(type);
        return (s != null) && (s.trim().length() > 0);
    }
}