com.edmunds.etm.agent.impl.ProcessController.java Source code

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Here is the source code for com.edmunds.etm.agent.impl.ProcessController.java

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/*
 * Copyright 2011 Edmunds.com, 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.edmunds.etm.agent.impl;

import com.edmunds.etm.agent.api.AgentConfig;
import com.edmunds.etm.agent.api.HealthCheck;
import com.edmunds.etm.agent.api.WebServerController;
import org.apache.commons.io.FileUtils;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.io.File;
import java.io.IOException;

/**
 * Controller for an external web server process.
 *
 * @author Ryan Holmes
 */
@Component
public class ProcessController implements WebServerController {

    private static final Logger logger = Logger.getLogger(ProcessController.class);

    // Process exit value indicating success
    private static final int PROCESS_SUCCESS_EXIT_VALUE = 0;

    private final AgentConfig agentConfig;

    @Autowired
    public ProcessController(AgentConfig agentConfig) {
        this.agentConfig = agentConfig;
        agentConfig.validate();
    }

    @Override
    public byte[] readRuleSetData() {
        File configFile = new File(agentConfig.getFilePath());

        byte[] configData = new byte[0];

        if (!configFile.exists()) {
            return configData;
        }

        try {
            configData = FileUtils.readFileToByteArray(configFile);
        } catch (IOException e) {
            String message = String.format("Could not read configuration file at path %s",
                    agentConfig.getFilePath());
            logger.error(message, e);
        }
        return configData;
    }

    @Override
    public void writeRuleSetData(byte[] ruleSetData) {
        File configFile = new File(agentConfig.getFilePath());
        try {
            FileUtils.writeByteArrayToFile(configFile, ruleSetData);
        } catch (IOException e) {
            String message = String.format("Could not write configuration file at path %s",
                    agentConfig.getFilePath());
            logger.error(message, e);
            throw new RuntimeException(message, e);
        }
    }

    @Override
    public boolean checkSyntax() {
        Process child;
        try {
            child = Runtime.getRuntime().exec(agentConfig.getSyntaxCheckCommand());
            child.waitFor();
        } catch (IOException e) {
            String message = "Could not execute syntax check";
            logger.error(message, e);
            return false;
        } catch (InterruptedException e) {
            String message = "Thread interrupted while waiting for syntax check";
            logger.error(message, e);
            return false;
        }

        return child.exitValue() == PROCESS_SUCCESS_EXIT_VALUE;
    }

    @Override
    public boolean start() {
        Process child;
        try {
            child = Runtime.getRuntime().exec(agentConfig.getStartCommand());
            child.waitFor();
        } catch (IOException e) {
            String message = "Could not execute Apache start command";
            logger.error(message, e);
            return false;
        } catch (InterruptedException e) {
            String message = "Thread interrupted while waiting for Apache start";
            logger.error(message, e);
            return false;
        }

        return child.exitValue() == PROCESS_SUCCESS_EXIT_VALUE;
    }

    @Override
    public boolean restart() {
        Process child;
        try {
            child = Runtime.getRuntime().exec(agentConfig.getRestartCommand());
            child.waitFor();
        } catch (IOException e) {
            String message = "Could not execute restart command";
            logger.error(message, e);
            return false;
        } catch (InterruptedException e) {
            String message = "Thread interrupted while waiting for restart";
            logger.error(message, e);
            return false;
        }

        return child.exitValue() == PROCESS_SUCCESS_EXIT_VALUE;
    }

    @Override
    public HealthCheck newHealthCheck() {
        return new TcpHealthCheck(agentConfig.getHostName(), agentConfig.getPort(), agentConfig.getCheckInterval(),
                agentConfig.getCheckTimeout());
    }
}