Improvement for demo for flow control by relation | 关联流量控制Demo

[westonlv]

Describe what happened (or what feature you want)

找了很多地方，没有找到关联流量控制的Demo，这里补充下。
这里先需要说明一下，关联流量控制生效的时间点为：B>threashold的时候A就会被限流。

import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.context.ContextUtil;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;

import java.util.Arrays;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;

/**
 * <br/>
 * 钉钉：1xd_zqcim4jtj5
 *
 * @author westonlv
 * @since 2019/2/21 11:05
 */
public class FlowQpsRelateDemo {
    static String node_read = "read";
    static String node_write = "write";

    public static void main(String[] args) {
        FlowRule rule = new FlowRule();
        rule.setResource(node_read);
        rule.setGrade(RuleConstant.FLOW_GRADE_QPS);
        rule.setStrategy(RuleConstant.STRATEGY_RELATE);
        rule.setCount(10);
        rule.setRefResource(node_write);
        FlowRuleManager.loadRules(Arrays.asList(rule));

        CyclicBarrier cyclicBarrier = new CyclicBarrier(2);

        Thread thread1 = new Thread(() -> {
            try {
                cyclicBarrier.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (BrokenBarrierException e) {
                e.printStackTrace();
            }
            for (int i = 0; i < 20; i++) {
                ContextUtil.enter("read");
                Entry entry = null;
                try {
                    entry = SphU.entry(node_read);
                    Thread.sleep(100);
                    System.out.println("read pass..");
                } catch (BlockException e) {
                    System.out.println("block read:" + (i - 10));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    if (null != entry)
                        entry.exit();
                    ContextUtil.exit();
                }
            }
            System.out.println("read over..");
        });
        thread1.start();

        Thread thread2 = new Thread(() -> {
            try {
                cyclicBarrier.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (BrokenBarrierException e) {
                e.printStackTrace();
            }
            for (int i = 0; i < 20; i++) {
                ContextUtil.enter("write");
                Entry entry = null;
                try {
                    entry = SphU.entry(node_write);
                    Thread.sleep(1);
                    System.out.println("write pass..");
                } catch (BlockException e) {
                    System.out.println("block write:" + (i - 10));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    if (null != entry)
                        entry.exit();
                    ContextUtil.exit();
                }
            }
            System.out.println("write over..");
        });
        thread2.start();

    }
}

===========================下方为测试结果============================

可以控制read资源和write资源sleep的时间产生不同的结果

write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write pass..
write over..
read pass..
block read:-9
block read:-8
block read:-7
block read:-6
block read:-5
block read:-4
block read:-3
block read:-2
block read:-1
block read:0
block read:1
block read:2
block read:3
block read:4
block read:5
block read:6
block read:7
block read:8
block read:9
read over..

[sczyh30]

Nice. 示例是否可以更加清晰一些？比如模拟以下情况：同时不断进行读写操作，一开始读和写操作都正常；然后接下来一段时间写操作增加（超过关联阈值），这时候关联限流生效，读操作被限流。

欢迎提交 PR 进行贡献，可以参考 贡献指南。

---

Nice, would you like to contribute a PR? You can refer to the contribution guidelines.

[westonlv]

Nice. 示例是否可以更加清晰一些？比如模拟以下情况：同时不断进行读写操作，一开始读和写操作都正常；然后接下来一段时间写操作增加（超过关联阈值），这时候关联限流生效，读操作被限流。

欢迎提交 PR 进行贡献，可以参考 贡献指南。

Nice, would you like to contribute a PR? You can refer to the contribution guidelines.

有些测试结果没有放上来，我整理下

[mark8866]

I had finished it.