com.netflix.exhibitor.core.state.FourLetterWord Maven / Gradle / Ivy

/*
 * Copyright 2012 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.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.io.CharStreams;
import com.netflix.exhibitor.core.config.InstanceConfig;
import com.netflix.exhibitor.core.config.IntConfigs;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.net.Socket;
import java.util.List;
import java.util.Map;

public class FourLetterWord
{
    private final String response;

    public enum Word
    {
        STAT,
        RUOK,
        REQS,
        DUMP,
        CONF,
        CONS,
        SRVR,
        WCHS,
        WCHC,
        WCHP,
        MNTR
    }

    public FourLetterWord(Word word, InstanceConfig config, int connectionTimeOutMs)
    {
        this(word, "localhost", config, connectionTimeOutMs);
    }
    
    public FourLetterWord(Word word, String hostname, InstanceConfig config, int connectionTimeOutMs)
    {
        Preconditions.checkNotNull(word);

        String  localResponse = "";
        Socket  s = null;
        try
        {
            s = new Socket(hostname, config.getInt(IntConfigs.CLIENT_PORT));
            s.setTcpNoDelay(true);
            s.setSoTimeout(connectionTimeOutMs);

            s.getOutputStream().write(word.name().toLowerCase().getBytes());
            s.getOutputStream().flush();

            localResponse = CharStreams.toString(new InputStreamReader(s.getInputStream()));
        }
        catch ( Exception e )
        {
            // ignore - treat as server not running
        }
        finally
        {
            try
            {
                if ( s != null )
                {
                    s.close();
                }
            }
            catch ( IOException e )
            {
                // ignore
            }
        }

        response = localResponse;
    }

    public List getResponseLines()
    {
        ImmutableList.Builder builder = ImmutableList.builder();
        BufferedReader                in = new BufferedReader(new StringReader(response));
        for(;;)
        {
            try
            {
                String      line = in.readLine();
                if ( line == null )
                {
                    break;
                }
                builder.add(line);
            }
            catch ( IOException ignore )
            {
                break;  // will never happen
            }
        }
        return builder.build();
    }

    public Map  getResponseMap()
    {
        ImmutableMap.Builder    builder = ImmutableMap.builder();
        for ( String line : getResponseLines() )
        {
            int     colonIndex = line.indexOf(':');
            if ( colonIndex > 0 )
            {
                String  name = line.substring(0, colonIndex);
                String  value = ((colonIndex + 1) < line.length()) ? line.substring(colonIndex + 1) : "";
                builder.put(name.toLowerCase(), value);
            }
        }

        return builder.build();
    }

    public String getResponse()
    {
        return response;
    }
}