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Support degrade by exception count (#174) 

* Add a new DegradeRule type, degrade by exception count in the last 60 seconds
* Add demo about degrading by exception count
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李豪 2018-10-11 16:39:38 +08:00 committed by GitHub
parent 570c3ee5b7
commit 9ae079c152
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6 changed files with 228 additions and 9 deletions
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11
sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/RuleConstant.java
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@ -15,6 +15,8 @@
*/
package com.alibaba.csp.sentinel.slots.block;
import com.alibaba.csp.sentinel.node.IntervalProperty;
/***
* @author youji.zj
* @author jialiang.linjl
@ -25,7 +27,14 @@ public final class RuleConstant {
public static final int FLOW_GRADE_QPS = 1;
public static final int DEGRADE_GRADE_RT = 0;
public static final int DEGRADE_GRADE_EXCEPTION = 1;
/**
* Degrade by biz exception ratio in the current {@link IntervalProperty#INTERVAL} second(s).
*/
public static final int DEGRADE_GRADE_EXCEPTION_RATIO = 1;
/**
* Degrade by biz exception count in the last 60 seconds.
*/
public static final int DEGRADE_GRADE_EXCEPTION_COUNT = 2;
public static final int AUTHORITY_WHITE = 0;
public static final int AUTHORITY_BLACK = 1;

7
sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRule.java
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@ -173,7 +173,7 @@ public class DegradeRule extends AbstractRule {
if (passCount.incrementAndGet() < RT_MAX_EXCEED_N) {
return true;
}
} else {
} else if (grade == RuleConstant.DEGRADE_GRADE_EXCEPTION_RATIO) {
double exception = clusterNode.exceptionQps();
double success = clusterNode.successQps();
long total = clusterNode.totalQps();
@ -190,6 +190,11 @@ public class DegradeRule extends AbstractRule {
if (exception / success < count) {
return true;
}
} else if (grade == RuleConstant.DEGRADE_GRADE_EXCEPTION_COUNT) {
double exception = clusterNode.totalException();
if (exception < count) {
return true;
}
}
synchronized (lock) {

32
sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeTest.java
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@ -82,7 +82,7 @@ public class DegradeTest {
rule.setCount(0.15);
rule.setResource(key);
rule.setTimeWindow(5);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION_RATIO);
when(cn.successQps()).thenReturn(8L);
@ -97,4 +97,34 @@ public class DegradeTest {
assertTrue(rule.passCheck(context, node, 1));
}
@Test
public void testExceptionCountModeDegrade() throws Throwable {
String key = "test_degrade_exception_count";
ClusterNode cn = mock(ClusterNode.class);
when(cn.totalException()).thenReturn(10L);
ClusterBuilderSlot.getClusterNodeMap().put(new StringResourceWrapper(key, EntryType.IN), cn);
Context context = mock(Context.class);
DefaultNode node = mock(DefaultNode.class);
when(node.getClusterNode()).thenReturn(cn);
DegradeRule rule = new DegradeRule();
rule.setCount(4);
rule.setResource(key);
rule.setTimeWindow(2);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION_COUNT);
when(cn.totalException()).thenReturn(4L);
// Will fail.
assertFalse(rule.passCheck(context, node, 1));
// Restore from the degrade timeout.
TimeUnit.SECONDS.sleep(3);
when(cn.totalException()).thenReturn(0L);
// Will pass.
assertTrue(rule.passCheck(context, node, 1));
}
}

169
sentinel-demo/sentinel-demo-basic/src/main/java/com/alibaba/csp/sentinel/demo/degrade/ExceptionCountDegradeDemo.java Normal file
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@ -0,0 +1,169 @@
package com.alibaba.csp.sentinel.demo.degrade;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.Tracer;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
import com.alibaba.csp.sentinel.util.TimeUtil;
/**
* <p>
* Degrade is used when the resources are in an unstable state, these resources
* will be degraded within the next defined time window. There are three ways to
* measure whether a resource is stable or not:
* <ul>
* <li>
* Exception count: When the exception count in the last 60 seconds greats than
* or equals to the threshold, access to the resource will be blocked in the
* coming time window.
* </li>
* <li>
* Exception ratio, see {@link ExceptionRatioDegradeDemo}.
* </li>
* <li>
* For average response time, see {@link RtDegradeDemo}.
* </li>
* </ul>
* </p>
* <p>
* Note: When degrading by {@link RuleConstant#DEGRADE_GRADE_EXCEPTION_COUNT}, time window
* less than 60 seconds will not work as expected. Because the exception count is
* summed by minute, when a short time window elapsed, the degradation condition
* may still be satisfied.
* </p>
*
* @author Carpenter Lee
*/
public class ExceptionCountDegradeDemo {
private static final String KEY = "abc";
private static AtomicInteger total = new AtomicInteger();
private static AtomicInteger pass = new AtomicInteger();
private static AtomicInteger block = new AtomicInteger();
private static AtomicInteger bizException = new AtomicInteger();
private static volatile boolean stop = false;
private static final int threadCount = 1;
private static int seconds = 60 + 40;
public static void main(String[] args) throws Exception {
tick();
initDegradeRule();
for (int i = 0; i < threadCount; i++) {
Thread entryThread = new Thread(new Runnable() {
@Override
public void run() {
int count = 0;
while (true) {
count++;
Entry entry = null;
try {
Thread.sleep(20);
entry = SphU.entry(KEY);
// token acquired, means pass
pass.addAndGet(1);
if (count % 2 == 0) {
// biz code raise an exception.
throw new RuntimeException("throw runtime ");
}
} catch (BlockException e) {
block.addAndGet(1);
} catch (Throwable t) {
bizException.incrementAndGet();
Tracer.trace(t);
} finally {
total.addAndGet(1);
if (entry != null) {
entry.exit();
}
}
}
}
});
entryThread.setName("working-thread");
entryThread.start();
}
}
private static void initDegradeRule() {
List<DegradeRule> rules = new ArrayList<DegradeRule>();
DegradeRule rule = new DegradeRule();
rule.setResource(KEY);
// set limit exception count to 4
rule.setCount(4);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION_COUNT);
/**
* When degrading by {@link RuleConstant#DEGRADE_GRADE_EXCEPTION_COUNT}, time window
* less than 60 seconds will not work as expected. Because the exception count is
* summed by minute, when a short time window elapsed, the degradation condition
* may still be satisfied.
*/
rule.setTimeWindow(10);
rules.add(rule);
DegradeRuleManager.loadRules(rules);
}
private static void tick() {
Thread timer = new Thread(new TimerTask());
timer.setName("sentinel-timer-task");
timer.start();
}
static class TimerTask implements Runnable {
@Override
public void run() {
long start = System.currentTimeMillis();
System.out.println("begin to statistic!!!");
long oldTotal = 0;
long oldPass = 0;
long oldBlock = 0;
long oldBizException = 0;
while (!stop) {
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
}
long globalTotal = total.get();
long oneSecondTotal = globalTotal - oldTotal;
oldTotal = globalTotal;
long globalPass = pass.get();
long oneSecondPass = globalPass - oldPass;
oldPass = globalPass;
long globalBlock = block.get();
long oneSecondBlock = globalBlock - oldBlock;
oldBlock = globalBlock;
long globalBizException = bizException.get();
long oneSecondBizException = globalBizException - oldBizException;
oldBizException = globalBizException;
System.out.println(TimeUtil.currentTimeMillis() + ", oneSecondTotal:" + oneSecondTotal
+ ", oneSecondPass:" + oneSecondPass
+ ", oneSecondBlock:" + oneSecondBlock
+ ", oneSecondBizException:" + oneSecondBizException);
if (seconds-- <= 0) {
stop = true;
}
}
long cost = System.currentTimeMillis() - start;
System.out.println("time cost: " + cost + " ms");
System.out.println("total:" + total.get() + ", pass:" + pass.get()
+ ", block:" + block.get() + ", bizException:" + bizException.get());
System.exit(0);
}
}
}

11
sentinel-demo/sentinel-demo-basic/src/main/java/com/alibaba/csp/sentinel/demo/degrade/ExceptionRatioDegradeDemo.java
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@ -32,13 +32,16 @@ import com.alibaba.csp.sentinel.util.TimeUtil;
/**
* <p>
* Degrade is used when the resources are in an unstable state, these resources
* will be degraded within the next defined time window. There are two ways to
* will be degraded within the next defined time window. There are three ways to
* measure whether a resource is stable or not:
* <ul>
* <li>
* Exception ratio: When the ratio of exception count per second and the success
* qps exceeds the threshold , access to the resource will be blocked in the
* coming window.
* qps greats than or equals to the threshold, access to the resource will be blocked
* in the coming time window.
* </li>
* <li>
* Exception Count, see {@link ExceptionCountDegradeDemo}.
* </li>
* <li>
* For average response time, see {@link RtDegradeDemo}.
@ -110,7 +113,7 @@ public class ExceptionRatioDegradeDemo {
rule.setResource(KEY);
// set limit exception ratio to 0.1
rule.setCount(0.1);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION);
rule.setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION_RATIO);
rule.setTimeWindow(10);
rules.add(rule);
DegradeRuleManager.loadRules(rules);

7
sentinel-demo/sentinel-demo-basic/src/main/java/com/alibaba/csp/sentinel/demo/degrade/RtDegradeDemo.java
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@ -35,8 +35,8 @@ import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
* <ul>
* <li>
* Average Response Time ('DegradeRule.Grade=RuleContants.DEGRADE_GRADE_RT'): When the
* average RT exceeds the threshold ('count' in 'DegradeRule', ms), the resource
* enters a quasi-degraded state. If the RT of next coming five requests still
* average RT greats than or equals to the threshold ('count' in 'DegradeRule', ms), the
* resource enters a quasi-degraded state. If the RT of next coming five requests still
* exceed this threshold, this resource will be downgraded, which means that in
* the next time window(Defined in 'timeWindow', s units) all the access to this
* resource will be blocked.
@ -44,6 +44,9 @@ import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
* <li>
* Exception ratio, see {@link ExceptionRatioDegradeDemo}.
* </li>
* <li>
* Exception Count, see {@link ExceptionCountDegradeDemo}.
* </li>
* </ul>
*
* </p>