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本文主要研究一下PowerJob的AbstractScriptProcessor

AbstractScriptProcessor

tech/powerjob/official/processors/impl/script/AbstractScriptProcessor.java

@Slf4j
public abstract class AbstractScriptProcessor extends CommonBasicProcessor {

    private static final ForkJoinPool POOL = new ForkJoinPool(4 * Runtime.getRuntime().availableProcessors());
    private static final Set<String> DOWNLOAD_PROTOCOL = Sets.newHashSet("http", "https", "ftp");
    protected static final String SH_SHELL = "/bin/sh";
    protected static final String CMD_SHELL = "cmd.exe";

    private static final String WORKER_DIR = PowerFileUtils.workspace() + "/official_script_processor/";

    @Override
    protected ProcessResult process0(TaskContext context) throws Exception {
        OmsLogger omsLogger = context.getOmsLogger();
        String scriptParams = CommonUtils.parseParams(context);
        omsLogger.info("[SYSTEM] ScriptProcessor start to process, params: {}", scriptParams);
        if (scriptParams == null) {
            String message = "[SYSTEM] ScriptParams is null, please check jobParam configuration.";
            omsLogger.warn(message);
            return new ProcessResult(false, message);
        }
        String scriptPath = prepareScriptFile(context.getInstanceId(), scriptParams);
        omsLogger.info("[SYSTEM] Generate executable file successfully, path: {}", scriptPath);
        
        if (SystemUtils.IS_OS_WINDOWS) {
            if (StringUtils.equals(getRunCommand(), SH_SHELL)) {
                String message = String.format("[SYSTEM] Current OS is %s where shell scripts cannot run.", SystemUtils.OS_NAME);
                omsLogger.warn(message);
                return new ProcessResult(false, message);
            }
        }

        // 授权
        if  ( !SystemUtils.IS_OS_WINDOWS) {
            ProcessBuilder chmodPb = new ProcessBuilder("/bin/chmod", "755", scriptPath);
            // 等待返回，这里不可能导致死锁（shell产生大量数据可能导致死锁）
            chmodPb.start().waitFor();
            omsLogger.info("[SYSTEM] chmod 755 authorization complete, ready to start execution~");
        }
        // 2. 执行目标脚本
        ProcessBuilder pb = StringUtils.equals(getRunCommand(), CMD_SHELL) ?
                new ProcessBuilder(getRunCommand(), "/c", scriptPath)
                : new ProcessBuilder(getRunCommand(), scriptPath);
        Process process = pb.start();

        StringBuilder inputBuilder = new StringBuilder();
        StringBuilder errorBuilder = new StringBuilder();

        boolean success = true;
        String result;

        final Charset charset = getCharset();
        try (InputStream is = process.getInputStream(); InputStream es = process.getErrorStream()) {

            POOL.execute(() -> copyStream(is, inputBuilder, omsLogger, charset));
            POOL.execute(() -> copyStream(es, errorBuilder, omsLogger, charset));

            success = process.waitFor() == 0;

        } catch (InterruptedException ie) {
            omsLogger.info("[SYSTEM] ScriptProcessor has been interrupted");
        } finally {
            result = String.format("[INPUT]: %s;[ERROR]: %s", inputBuilder.toString(), errorBuilder.toString());
        }
        return new ProcessResult(success, result);
    }

    /**
     * 生成脚本名称
     * @param instanceId id of instance
     * @return 文件名称
     */
    protected abstract String getScriptName(Long instanceId);

    /**
     * 获取运行命令（eg，shell返回 /bin/sh）
     * @return 执行脚本的命令
     */
    protected abstract String getRunCommand();

    //......
}    

AbstractScriptProcessor继承了CommonBasicProcessor，它定义了一个parallelism为4*Runtime.getRuntime().availableProcessors()的ForkJoinPool；其process0方法先读取scriptParams，然后执行prepareScriptFile获取scriptPath，接着使用chmod变更script权限为755，然后通过getRunCommand获取命令，接着往pool提交copyStream，等待process返回

prepareScriptFile

    private String prepareScriptFile(Long instanceId, String processorInfo) throws IOException {
        String scriptPath = WORKER_DIR + getScriptName(instanceId);
        File script = new File(scriptPath);
        if (script.exists()) {
            return scriptPath;
        }
        File dir = new File(script.getParent());
        boolean success = dir.mkdirs();
        success = script.createNewFile();
        if (!success) {
            throw new RuntimeException("create script file failed");
        }

        // 如果是下载链接，则从网络获取
        for (String protocol : DOWNLOAD_PROTOCOL) {
            if (processorInfo.startsWith(protocol)) {
                FileUtils.copyURLToFile(new URL(processorInfo), script, 5000, 300000);
                return scriptPath;
            }
        }

        final Charset charset = getCharset();

        if(charset != null)
        {
            try (Writer fstream = new OutputStreamWriter(Files.newOutputStream(script.toPath()), charset); BufferedWriter out = new BufferedWriter(fstream)) {
                out.write(processorInfo);
                out.flush();
            }
        }
        else {
            try (FileWriter fw = new FileWriter(script); BufferedWriter bw = new BufferedWriter(fw)) {
                bw.write(processorInfo);
                bw.flush();
            }
        }
        return scriptPath;
    }

prepareScriptFile先通过getScriptName获取scriptPath，如果是http、https、ftp链接则通过FileUtils.copyURLToFile下载，否则把scriptParams写入到scriptPath

copyStream

    private static void copyStream(InputStream is, StringBuilder sb, OmsLogger omsLogger, Charset charset) {
        String line;
        try (BufferedReader br = new BufferedReader(new InputStreamReader(is, charset))) {
            while ((line = br.readLine()) != null) {
                sb.append(line);
                // 同步到在线日志
                omsLogger.info(line);
            }
        } catch (Exception e) {
            log.warn("[ScriptProcessor] copyStream failed.", e);
            omsLogger.warn("[SYSTEM] copyStream failed.", e);

            sb.append("Exception: ").append(e);
        }
    }

copyStream会读取InputStream到StringBuilder，同时打印到omsLogger

ShellProcessor

tech/powerjob/official/processors/impl/script/ShellProcessor.java

public class ShellProcessor extends AbstractScriptProcessor {

    @Override
    protected String getScriptName(Long instanceId) {
        return String.format("shell_%d.sh", instanceId);
    }

    @Override
    protected String getRunCommand() {
        return SH_SHELL;
    }
}

ShellProcessor的getScriptName是基于shell_%d.sh和instanceId生成的；其getRunCommand为/bin/sh

CMDProcessor

tech/powerjob/official/processors/impl/script/CMDProcessor.java

public class CMDProcessor extends AbstractScriptProcessor {

    @Override
    protected String getScriptName(Long instanceId) {
        return String.format("cmd_%d.bat", instanceId);
    }

    @Override
    protected String getRunCommand() {
        return "cmd.exe";
    }

    @Override
    protected Charset getCharset() {
        return Charset.defaultCharset();
    }
}

CMDProcessor的getScriptName是基于cmd_%d.bat和instanceId生成，其getRunCommand为`cmd.exe

PowerShellProcessor

tech/powerjob/official/processors/impl/script/PowerShellProcessor.java

public class PowerShellProcessor extends AbstractScriptProcessor {

    @Override
    protected String getScriptName(Long instanceId) {
        return String.format("powershell_%d.ps1", instanceId);
    }

    @Override
    protected String getRunCommand() {
        return "powershell.exe";
    }

    @Override
    protected Charset getCharset() {
        return Charset.defaultCharset();
    }
}

PowerShellProcessor的getScriptName是基于powershell_%d.ps1"和instanceId生成，其getRunCommand为powershell.exe

PythonProcessor

tech/powerjob/official/processors/impl/script/PythonProcessor.java

public class PythonProcessor extends AbstractScriptProcessor {

    @Override
    protected String getScriptName(Long instanceId) {
        return String.format("python_%d.py", instanceId);
    }

    @Override
    protected String getRunCommand() {
        return "python";
    }
}

PythonProcessor的getScriptName是基于python_%d.py和instanceId生成，其getRunCommand为python

小结

AbstractScriptProcessor继承了CommonBasicProcessor，它有四个实现类分别是ShellProcessor、CMDProcessor、PowerShellProcessor、PythonProcessor；它定义了getScriptName、getRunCommand抽象方法；其process0方法主要是把scriptParams写入到本地文件(scriptParams是http、https、ftp的则根据url进行下载)，然后修改权限为755，然后执行pb.start()，再将input及errorStream收集到StringBuilder并打印到omsLogger，最后process.waitFor()等待处理完成。