Drools规则调用与死循环问题排查

一.drools规则依赖

在maven的pom.xml文件，引入下面依赖：

<properties>
    <drools.version>7.6.0.Final</drools.version>
</properties>


<dependency>
    <groupId>org.kie</groupId>
    <artifactId>kie-api</artifactId>
    <version>${drools.version}</version>
</dependency>
<dependency>
    <groupId>org.drools</groupId>
    <artifactId>drools-core</artifactId>
    <version>${drools.version}</version>
</dependency>
<dependency>
    <groupId>org.drools</groupId>
    <artifactId>drools-compiler</artifactId>
    <version>${drools.version}</version>
</dependency>
<dependency>
    <groupId>org.drools</groupId>
    <artifactId>drools-decisiontables</artifactId>
    <version>${drools.version}</version>
</dependency>
<dependency>
    <groupId>org.drools</groupId>
    <artifactId>drools-templates</artifactId>
    <version>${drools.version}</version>
</dependency>

二.drools规则编译配置

在工程src/main/resources/META-INF/kmodule.xml 文件中配置规则信息；

若kmodule.xml不存在新建,编译器会根据此文件进行规则编译。

配置内容如下:

<?xml version="1.0" encoding="UTF-8"?>

</kbase>

</kbase>

</kmodule>

说明:

kmodule: 可包含多个kbase子节点。

kbase.name: 配置kbase节点name是唯一的既不能重名

kbase.packages: 配置drools规则包(*.drl)文件,可定义多个包,用逗号隔开;在src/main/resources下面的文件夹(如：rules.audit表示src/main/resources/rules/audit目录)名称。

ksession.name：配置ksession名称，任意字符串但不能重名，可以有多个。

ksession.type：配置ksession类型，默认为有状态，stateless表示无状态。

注意:

在运行时、KieContainer会根据*Model对象来创建KieModule，KieBase，KieSession对象，其中KieModule和KieBase只会创建一次，而KieSession则可能创建多次

三.drools规则配置

1) OrderAudit-1.0.0.1.drl规则文件配置：

在src/main/resources/rules/audit目录下创建OrderAudit-1.0.0.1.drl规则文件，内容如下：

package order_audit_setting_rules;

import com.eron.order.OrderAudit

// 订单不审核

rule "do not audit"

salience 1200

when

$a:OrderAudit(logisticsStatus not in (0,1))

then

modify($a){

setOrderStatus( 10004 )

}

end

// 订单审核拒绝

rule "DECLINE STAY"

no-loop true

salience 2450

when

$a:OrderAudit(orderStatus not in (1))

then

modify( $a ) {

setAuditMessage("拟审核拒绝不调额"),

setOrderStatus(1),

setLogisticsStatus(2)

}

end

2) OrderSms-1.0.0.1.drl规则文件配置：

在src/main/resources/rules/sms目录下创建OrderSms-1.0.0.1.drl规则文件，内容如下：

package order_sms_setting_rules;

import com.eron.order.OrderAudit

rule "greater than 2 rule"

when

$a:UserInfo(userId != null,userId > 2);

then

$a.setPushType(2);

$a.setTemplateId("SMS_T10_TEMPLATE");

end

rule "other"

when

$a:UserInfo(userId != null,userId <= 2);

then

$a.setPushType(1);

$a.setTemplateId("SMS_T2_TEMPLATE");

End

四.drools规则模型

1)OrderAudit-1.0.0.1.drl规则模型

/***

* 订单审核

* @date 2019/09/17

public class OrderAudit implements Serializable{

static final long serialVersionUID = 1L;

@Label("用户Id")

private Long userId;

@Label("订单状态")

private Integer orderStatus;

@Label("物流状态")

private Integer logisticsStatus;

@Label("审核信息")

private String auditMessage;

......

}

2)OrderSms-1.0.0.1.drl规则模型

/***

* 用户信息

* @date 2019/09/17

public class UserInfo implements Serializable{

static final long serialVersionUID = 1L;

@Label("用户Id")

private Long userId;

@Label("模板类型")

private Integer pushType ;

@Label("模板Id")

private String templateId;

......

}

五.drools规则调用

1.StatelessKieSession无状态调用

public class StatelessKieSessionDroolsRuleTest {

    public static void main(String[] args) {

        invokeSimpleRowStatelessKieSessionDroolsRule();

        System.out.println("----------------------------------");

        invokeMoreRowStatelessKieSessionDroolsRule();

/**

     * 有会话状态-多行调用规则

*/

    private static void invokeMoreRowStatelessKieSessionDroolsRule(){

        //执行规则

        List<Command> cmds = new ArrayList<>();

        for (int userIndex = 0; userIndex < 4; userIndex++) {

            UserInfo userInfo = new UserInfo();

            userInfo.setUserId(Long.valueOf(userIndex+1));

            System.out.println("规则入参：" + JsonUtil.convertToJson(userInfo));

            cmds.add(CommandFactory.newInsert(userInfo, String.valueOf(userIndex)));

        //填充规则

        cmds.add(CommandFactory.newFireAllRules());

        //执行规则

        ExecutionResults results = getStatelessKieSession().execute(CommandFactory.newBatchExecution(cmds));

        for (int userIndex = 0; userIndex < 4; userIndex++) {

            Object userObject = results.getValue(String.valueOf(userIndex));

            UserInfo userInfo = (UserInfo) userObject;

            System.out.println("规则出参：" + JsonUtil.convertToJson(userInfo));

/**

     * 有会话状态-单行调用规则

*/

    private static void invokeSimpleRowStatelessKieSessionDroolsRule(){

        UserInfo userInfo = new UserInfo();

        userInfo.setUserId(1000L);

        //执行规则

        System.out.println("规则入参：" + JsonUtil.convertToJson(userInfo));

        StatelessKieSession statelessKieSession = getStatelessKieSession();

        statelessKieSession.execute(userInfo);

        System.out.println("规则出参：" + JsonUtil.convertToJson(userInfo));

/**

     * 获取无状态KieSession会话

     * @return

*/

    private static StatelessKieSession getStatelessKieSession(){

        //根据KieServices.Factory工厂,创建KieServices类

        KieServices kieServices = KieServices.Factory.get();

        //从KieServices中,获得KieContainer实例,其会加载kmodule.xml文件与所有DRL规则文件，并将该编译结果KieModule放在KieContainer容器。

        KieContainer kieContainer = kieServices.getKieClasspathContainer();

        //建立KieSession到规则文件的通信管道

        StatelessKieSession statelessKieSession = kieContainer.newStatelessKieSession("ksession-sms");

        return statelessKieSession;

规则结果：

【单行调用】

规则入参：{"userId":1000,"pushType":null,"templateId":null}

规则出参：{"userId":1000,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

【多行调用】

规则入参：{"userId":1,"pushType":null,"templateId":null}

规则入参：{"userId":2,"pushType":null,"templateId":null}

规则入参：{"userId":3,"pushType":null,"templateId":null}

规则入参：{"userId":4,"pushType":null,"templateId":null}

规则出参：{"userId":1,"pushType":1,"templateId":"SMS_T2_TEMPLATE"}

规则出参：{"userId":2,"pushType":1,"templateId":"SMS_T2_TEMPLATE"}

规则出参：{"userId":3,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

规则出参：{"userId":4,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

2.KieSession有状态调用

public class KieSessionDroolsRuleTest {

    public static void main(String[] args) {

        invokeSimpleRowKieSessionDroolsRule();

        System.out.println("----------------------------------");

        invokeMoreRowKieSessionDroolsRule();

/**

     * 有会话状态：多行调用规则

*/

    private static void invokeMoreRowKieSessionDroolsRule(){

        List<Command> cmds = new ArrayList<>();

        for (int auditIndex = 0; auditIndex < 5; auditIndex++) {

            OrderAudit orderAudit = new OrderAudit();

            orderAudit.setUserId(Long.valueOf(auditIndex));

            orderAudit.setOrderStatus(2);

            System.out.println("规则入参：" + JsonUtil.convertToJson(orderAudit));

            cmds.add(CommandFactory.newInsert(orderAudit, String.valueOf(auditIndex)));

        //填充规则

        cmds.add(CommandFactory.newFireAllRules());

        //执行规则

        ExecutionResults results = getKieSession().execute(CommandFactory.newBatchExecution(cmds));

        for (int auditIndex = 0; auditIndex < 5; auditIndex++) {

            Object auditObject = results.getValue(String.valueOf(auditIndex));

            OrderAudit orderAudit = (OrderAudit) auditObject;

            System.out.println("规则出参：" + JsonUtil.convertToJson(orderAudit));

/**

     * 有会话状态：单行调用规则

*/

    private static void invokeSimpleRowKieSessionDroolsRule(){

        OrderAudit orderAudit = new OrderAudit();

        orderAudit.setUserId(Long.valueOf(1000));

        orderAudit.setOrderStatus(2);

        System.out.println("规则入参：" + JsonUtil.convertToJson(orderAudit));

        //执行规则

        KieSession kieSession = getKieSession();

        kieSession.insert(orderAudit);

        kieSession.fireAllRules();

        System.out.println("规则出参：" + JsonUtil.convertToJson(orderAudit));

/**

     * 获取有状态KieSession会话

     * @return

*/

    private static KieSession getKieSession(){

        //根据KieServices.Factory工厂,创建KieServices类

        KieServices kieServices = KieServices.Factory.get();

        //从KieServices中,获得KieContainer实例,其会加载kmodule.xml文件与所有DRL规则文件，并将该编译结果KieModule放在KieContainer容器。

        KieContainer kieContainer = kieServices.getKieClasspathContainer();

        //建立KieSession到规则文件的通信管道

        KieSession kieSession = kieContainer.newKieSession("ksession-audit");

        return kieSession;

注意：

1）如果引擎内部因为对Fact更新引起引擎再次启动检查规则，那么它会忽略掉所有的no-loop属性设置为true的规则。

2）本案例主要验证"DECLINE STAY"与"do not audit"在对Fact更新引起引擎再次启动检查规则,造成死循环。

六.drools常见问题

1) salience优先级

作用：设置规则执行的优先级，值是一个数字，数字越大执行的优先级越高，它的值可以是一个负数，默认值是0如果我们不手动设置salience属性值，则执行顺序是随机的。

2) no-loop防止死循环

在一个规则中如果条件满足就对Working Memory当中的某个Fact对象进行修改，比如使用update将其更新到当前的Working Memory当中，这时候引擎会再次检查所有的规则是否满足条件，如果满足会再执行，可能会出现死循环

作用：用来控制已经执行过的规则条件再次满足时是否再次执行，默认是false，如果属性值是true，表示该规则只会被规则引擎检查一次，如果满足条件就执行规则的RHS部分。

3)引擎内部因为对Fact更新引起引擎再次启动检查规则，那么它会忽略掉所有的no-loop属性设置为true的规则,造成死循环。

问题：案例"DECLINE STAY"与"do not audit"在对Fact更新引起引擎再次启动检查规则,造成死循环。

排查方法：

1)top:查看机器性能,找到java进程号30411

[root@eronfat026053 ~]# top

top - 14:55:21 up 525 days, 19 min, 2 users, load average: 0.95, 0.78, 0.87

Tasks: 135 total, 1 running, 128 sleeping, 6 stopped, 0 zombie

%Cpu(s): 0.3 us, 0.3 sy, 0.0 ni, 96.4 id, 0.0 wa, 0.0 hi, 0.0 si, 3.0 st

KiB Mem : 3684076 total, 155468 free, 3333552 used, 195056 buff/cache

KiB Swap: 4194300 total, 3047360 free, 1146940 used. 129496 avail Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

30411 root 20 0 6049216 2.614g 5980 S 2.3 74.4 338:36.87 java

5380 root 20 0 1336896 39880 1572 S 1.7 1.1 266:51.01 titanagent

5382 root 9 -11 87648 792 448 S 1.0 0.0 230:15.12 titan_monitor

26 root 20 0 0 0 0 S 0.3 0.0 392:33.12 rcuos/0

413 root 20 0 0 0 0 S 0.3 0.0 219:49.21 xfsaild/dm-0

1 root 20 0 392008 265036 1216 S 0.0 7.2 134:43.78 systemd

2 root 20 0 0 0 0 S 0.0 0.0 0:04.66 kthreadd

2)top -Hp 30411:查看java进程中各个线程情况，找到占用cpu最高的java线程号

[root@eronfat026053 ~]# top -Hp 30411

top - 14:57:04 up 525 days, 21 min, 2 users, load average: 0.61, 0.69, 0.83

Threads: 159 total, 3 running, 156 sleeping, 0 stopped, 0 zombie

%Cpu(s): 20.9 us, 4.1 sy, 0.0 ni, 48.4 id, 0.0 wa, 0.0 hi, 0.2 si, 26.4 st

KiB Mem : 3684076 total, 171700 free, 3329680 used, 182696 buff/cache

KiB Swap: 4194300 total, 3042080 free, 1152220 used. 139536 avail Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

30533 root 20 0 6055788 2.616g 12560 R 49.8 74.5 295:44.24 java

30537 root 20 0 6055788 2.616g 12560 S 8.3 74.5 0:09.93 java

30419 root 20 0 6055788 2.616g 12560 S 2.7 74.5 2:20.23 java

30538 root 20 0 6055788 2.616g 12560 S 1.3 74.5 0:09.39 java

30415 root 20 0 6055788 2.616g 12560 S 1.0 74.5 1:20.05 java

30535 root 20 0 6055788 2.616g 12560 S 1.0 74.5 0:10.14 java

3)jstack 30533 > /tmp/pid-30533.txt :输出各个线程执行到哪个方法导致的CPU飙升
vi /tmp/ pid-30533.txt 内容如下：

Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.144-b01 mixed mode):

"main" #1 prio=5 os_prio=0 tid=0x000000000207f000 nid=0x3c30 runnable [0x00000000021be000]

java.lang.Thread.State: RUNNABLE

at java.lang.Object.notifyAll(Native Method)

at org.drools.core.phreak.SynchronizedPropagationList.notifyWaitOnRest(SynchronizedPropagationList.java:137)

- eliminated <0x00000006c1fe9178> (a org.drools.core.phreak.SynchronizedPropagationList)

at org.drools.core.phreak.SynchronizedPropagationList.internalAddEntry(SynchronizedPropagationList.java:71)

- locked <0x00000006c1fe9178> (a org.drools.core.phreak.SynchronizedPropagationList)

at org.drools.core.phreak.SynchronizedPropagationList.addEntry(SynchronizedPropagationList.java:64)

at org.drools.core.common.DefaultAgenda.addPropagation(DefaultAgenda.java:1260)

at org.drools.core.impl.StatefulKnowledgeSessionImpl.addPropagation(StatefulKnowledgeSessionImpl.java:2052)

at org.drools.core.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:251)

at org.drools.core.common.NamedEntryPoint.update(NamedEntryPoint.java:423)

at org.drools.core.common.NamedEntryPoint.update(NamedEntryPoint.java:413)

at org.drools.core.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:411)

at order_audit_setting_rules.Rule_DECLINE_STAY1012618649.defaultConsequence(Rule_DECLINE_STAY1012618649.java:11)

at order_audit_setting_rules.Rule_DECLINE_STAY1012618649DefaultConsequenceInvokerGenerated.evaluate(Unknown Source)

at order_audit_setting_rules.Rule_DECLINE_STAY1012618649DefaultConsequenceInvoker.evaluate(Unknown Source)

at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:431)

at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:379)

at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:135)

at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:88)

at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:34)

at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)

at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1067)

at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1014)

at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1006)

at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1318)

at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1309)

at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1293)

at com.eron.service.KieSessionDroolsRuleTest.invokeSimpleRowKieSessionDroolsRule(KieSessionDroolsRuleTest.java:59)

at com.eron.service.KieSessionDroolsRuleTest.main(KieSessionDroolsRuleTest.java:18)

"VM Thread" os_prio=2 tid=0x000000001bbf4000 nid=0x5cc runnable

"GC task thread#0 (ParallelGC)" os_prio=0 tid=0x0000000001f61000 nid=0x4190 runnable

"VM Periodic Task Thread" os_prio=2 tid=0x000000001d911000 nid=0x215c waiting on condition

JNI global references: 420