Dubbo里面线程池的拒绝策略

Dubbo里面线程池的拒绝策略

public class AbortPolicyWithReport extends ThreadPoolExecutor.AbortPolicy {

    protected static final Logger logger = LoggerFactory.getLogger(AbortPolicyWithReport.class);

    private final String threadName;

    private final URL url;

    private static volatile long lastPrintTime = 0;

    private static Semaphore guard = new Semaphore(1);

    public AbortPolicyWithReport(String threadName, URL url) {
        this.threadName = threadName;
        this.url = url;
    }

    @Override
    public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
        String msg = String.format("Thread pool is EXHAUSTED!" +
                        " Thread Name: %s, Pool Size: %d (active: %d, core: %d, max: %d, largest: %d), Task: %d (completed: %d)," +
                        " Executor status:(isShutdown:%s, isTerminated:%s, isTerminating:%s), in %s://%s:%d!",
                threadName, e.getPoolSize(), e.getActiveCount(), e.getCorePoolSize(), e.getMaximumPoolSize(), e.getLargestPoolSize(),
                e.getTaskCount(), e.getCompletedTaskCount(), e.isShutdown(), e.isTerminated(), e.isTerminating(),
                url.getProtocol(), url.getIp(), url.getPort());
        logger.warn(msg);
        dumpJStack();
        throw new RejectedExecutionException(msg);
    }

    private void dumpJStack() {
        long now = System.currentTimeMillis();

        //dump every 10 minutes
      	//每 10 分钟，只打印一次。
        if (now - lastPrintTime < 10 * 60 * 1000) {
            return;
        }
		//获得信号量。保证，同一时间，有且仅有一个线程执行打印。
        if (!guard.tryAcquire()) {
            return;
        }
		//// 创建线程池，后台执行打印 JStack
        Executors.newSingleThreadExecutor().execute(new Runnable() {
            @Override
            public void run() {
              	// 获得路径
                String dumpPath = url.getParameter(Constants.DUMP_DIRECTORY, System.getProperty("user.home"));

                SimpleDateFormat sdf;
                // 获得系统
                String OS = System.getProperty("os.name").toLowerCase();

                // window system don't support ":" in file name
                if(OS.contains("win")){
                    sdf = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
                }else {
                    sdf = new SimpleDateFormat("yyyy-MM-dd_HH:mm:ss");
                }

                String dateStr = sdf.format(new Date());
              	// 获得输出流
                FileOutputStream jstackStream = null;
                try {
                    jstackStream = new FileOutputStream(new File(dumpPath, "Dubbo_JStack.log" + "." + dateStr));
                  	// 打印 JStack
                    JVMUtil.jstack(jstackStream);
                } catch (Throwable t) {
                    logger.error("dump jstack error", t);
                } finally {
                  // 释放信号量
                    guard.release();
                  // 释放输出流
                    if (jstackStream != null) {
                        try {
                            jstackStream.flush();
                            jstackStream.close();
                        } catch (IOException e) {
                        }
                    }
                }
				// 记录最后打印时间
                lastPrintTime = System.currentTimeMillis();
            }
        });

    }

}

public class JVMUtil {
    public static void jstack(OutputStream stream) throws Exception {
        ThreadMXBean threadMxBean = ManagementFactory.getThreadMXBean();
        for (ThreadInfo threadInfo : threadMxBean.dumpAllThreads(true, true)) {
            stream.write(getThreadDumpString(threadInfo).getBytes());
        }
    }

    private static String getThreadDumpString(ThreadInfo threadInfo) {
        StringBuilder sb = new StringBuilder(""" + threadInfo.getThreadName() + """ +
                " Id=" + threadInfo.getThreadId() + " " +
                threadInfo.getThreadState());
        if (threadInfo.getLockName() != null) {
            sb.append(" on " + threadInfo.getLockName());
        }
        if (threadInfo.getLockOwnerName() != null) {
            sb.append(" owned by "" + threadInfo.getLockOwnerName() +
                    "" Id=" + threadInfo.getLockOwnerId());
        }
        if (threadInfo.isSuspended()) {
            sb.append(" (suspended)");
        }
        if (threadInfo.isInNative()) {
            sb.append(" (in native)");
        }
        sb.append('
');
        int i = 0;

        StackTraceElement[] stackTrace = threadInfo.getStackTrace();
        MonitorInfo[] lockedMonitors = threadInfo.getLockedMonitors();
        for (; i < stackTrace.length && i < 32; i++) {
            StackTraceElement ste = stackTrace[i];
            sb.append("	at " + ste.toString());
            sb.append('
');
            if (i == 0 && threadInfo.getLockInfo() != null) {
                Thread.State ts = threadInfo.getThreadState();
                switch (ts) {
                    case BLOCKED:
                        sb.append("	-  blocked on " + threadInfo.getLockInfo());
                        sb.append('
');
                        break;
                    case WAITING:
                        sb.append("	-  waiting on " + threadInfo.getLockInfo());
                        sb.append('
');
                        break;
                    case TIMED_WAITING:
                        sb.append("	-  waiting on " + threadInfo.getLockInfo());
                        sb.append('
');
                        break;
                    default:
                }
            }

            for (MonitorInfo mi : lockedMonitors) {
                if (mi.getLockedStackDepth() == i) {
                    sb.append("	-  locked " + mi);
                    sb.append('
');
                }
            }
        }
        if (i < stackTrace.length) {
            sb.append("	...");
            sb.append('
');
        }

        LockInfo[] locks = threadInfo.getLockedSynchronizers();
        if (locks.length > 0) {
            sb.append("
	Number of locked synchronizers = " + locks.length);
            sb.append('
');
            for (LockInfo li : locks) {
                sb.append("	- " + li);
                sb.append('
');
            }
        }
        sb.append('
');
        return sb.toString();
    }
}