Drools規則調用與死循環問題排查

一.drools規則依賴

在maven的pom.xml文件，引入下面依賴：

<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規則編譯配置

在工程src/main/resources/META-INF/kmodule.xml 文件中配置規則信息；

若kmodule.xml不存在新建,編譯器會根據此文件進行規則編譯。

配置內容如下:

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

</kbase>

</kbase>

</kmodule>

說明:

kmodule: 可包含多個kbase子節點。

kbase.name: 配置kbase節點name是唯一的既不能重名

kbase.packages: 配置drools規則包(*.drl)文件,可定義多個包,用逗號隔開;在src/main/resources下面的文件夾(如：rules.audit表示src/main/resources/rules/audit目錄)名稱。

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

ksession.type：配置ksession類型，默認爲有狀態，stateless表示無狀態。

注意:

在運行時、KieContainer會根據*Model對象來創建KieModule，KieBase，KieSession對象，其中KieModule和KieBase只會創建一次，而KieSession則可能創建多次

三.drools規則配置

1) OrderAudit-1.0.0.1.drl規則文件配置：

在src/main/resources/rules/audit目錄下創建OrderAudit-1.0.0.1.drl規則文件，內容如下：

package order_audit_setting_rules;

import com.eron.order.OrderAudit

// 訂單不審覈

rule "do not audit"

salience 1200

when

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

then

modify($a){

setOrderStatus( 10004 )

}

end

// 訂單審覈拒絕

rule "DECLINE STAY"

no-loop true

salience 2450

when

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

then

modify( $a ) {

setAuditMessage("擬審覈拒絕不調額"),

setOrderStatus(1),

setLogisticsStatus(2)

}

end

2) OrderSms-1.0.0.1.drl規則文件配置：

在src/main/resources/rules/sms目錄下創建OrderSms-1.0.0.1.drl規則文件，內容如下：

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規則模型

1)OrderAudit-1.0.0.1.drl規則模型

/***

* 訂單審覈

* @date 2019/09/17

public class OrderAudit implements Serializable{

static final long serialVersionUID = 1L;

@Label("用戶Id")

private Long userId;

@Label("訂單狀態")

private Integer orderStatus;

@Label("物流狀態")

private Integer logisticsStatus;

@Label("審覈信息")

private String auditMessage;

......

}

2)OrderSms-1.0.0.1.drl規則模型

/***

* 用戶信息

* @date 2019/09/17

public class UserInfo implements Serializable{

static final long serialVersionUID = 1L;

@Label("用戶Id")

private Long userId;

@Label("模板類型")

private Integer pushType ;

@Label("模板Id")

private String templateId;

......

}

五.drools規則調用

1.StatelessKieSession無狀態調用

public class StatelessKieSessionDroolsRuleTest {

    public static void main(String[] args) {

        invokeSimpleRowStatelessKieSessionDroolsRule();

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

        invokeMoreRowStatelessKieSessionDroolsRule();

/**

     * 有會話狀態-多行調用規則

*/

    private static void invokeMoreRowStatelessKieSessionDroolsRule(){

        //執行規則

        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("規則入參：" + JsonUtil.convertToJson(userInfo));

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

        //填充規則

        cmds.add(CommandFactory.newFireAllRules());

        //執行規則

        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("規則出參：" + JsonUtil.convertToJson(userInfo));

/**

     * 有會話狀態-單行調用規則

*/

    private static void invokeSimpleRowStatelessKieSessionDroolsRule(){

        UserInfo userInfo = new UserInfo();

        userInfo.setUserId(1000L);

        //執行規則

        System.out.println("規則入參：" + JsonUtil.convertToJson(userInfo));

        StatelessKieSession statelessKieSession = getStatelessKieSession();

        statelessKieSession.execute(userInfo);

        System.out.println("規則出參：" + JsonUtil.convertToJson(userInfo));

/**

     * 獲取無狀態KieSession會話

     * @return

*/

    private static StatelessKieSession getStatelessKieSession(){

        //根據KieServices.Factory工廠,創建KieServices類

        KieServices kieServices = KieServices.Factory.get();

        //從KieServices中,獲得KieContainer實例,其會加載kmodule.xml文件與所有DRL規則文件，並將該編譯結果KieModule放在KieContainer容器。

        KieContainer kieContainer = kieServices.getKieClasspathContainer();

        //建立KieSession到規則文件的通信管道

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

        return statelessKieSession;

規則結果：

【單行調用】

規則入參：{"userId":1000,"pushType":null,"templateId":null}

規則出參：{"userId":1000,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

【多行調用】

規則入參：{"userId":1,"pushType":null,"templateId":null}

規則入參：{"userId":2,"pushType":null,"templateId":null}

規則入參：{"userId":3,"pushType":null,"templateId":null}

規則入參：{"userId":4,"pushType":null,"templateId":null}

規則出參：{"userId":1,"pushType":1,"templateId":"SMS_T2_TEMPLATE"}

規則出參：{"userId":2,"pushType":1,"templateId":"SMS_T2_TEMPLATE"}

規則出參：{"userId":3,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

規則出參：{"userId":4,"pushType":2,"templateId":"SMS_T10_TEMPLATE"}

2.KieSession有狀態調用

public class KieSessionDroolsRuleTest {

    public static void main(String[] args) {

        invokeSimpleRowKieSessionDroolsRule();

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

        invokeMoreRowKieSessionDroolsRule();

/**

     * 有會話狀態：多行調用規則

*/

    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("規則入參：" + JsonUtil.convertToJson(orderAudit));

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

        //填充規則

        cmds.add(CommandFactory.newFireAllRules());

        //執行規則

        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("規則出參：" + JsonUtil.convertToJson(orderAudit));

/**

     * 有會話狀態：單行調用規則

*/

    private static void invokeSimpleRowKieSessionDroolsRule(){

        OrderAudit orderAudit = new OrderAudit();

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

        orderAudit.setOrderStatus(2);

        System.out.println("規則入參：" + JsonUtil.convertToJson(orderAudit));

        //執行規則

        KieSession kieSession = getKieSession();

        kieSession.insert(orderAudit);

        kieSession.fireAllRules();

        System.out.println("規則出參：" + JsonUtil.convertToJson(orderAudit));

/**

     * 獲取有狀態KieSession會話

     * @return

*/

    private static KieSession getKieSession(){

        //根據KieServices.Factory工廠,創建KieServices類

        KieServices kieServices = KieServices.Factory.get();

        //從KieServices中,獲得KieContainer實例,其會加載kmodule.xml文件與所有DRL規則文件，並將該編譯結果KieModule放在KieContainer容器。

        KieContainer kieContainer = kieServices.getKieClasspathContainer();

        //建立KieSession到規則文件的通信管道

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

        return kieSession;

注意：

1）如果引擎內部因爲對Fact更新引起引擎再次啓動檢查規則，那麼它會忽略掉所有的no-loop屬性設置爲true的規則。

2）本案例主要驗證"DECLINE STAY"與"do not audit"在對Fact更新引起引擎再次啓動檢查規則,造成死循環。

六.drools常見問題

1) salience優先級

作用：設置規則執行的優先級，值是一個數字，數字越大執行的優先級越高，它的值可以是一個負數，默認值是0如果我們不手動設置salience屬性值，則執行順序是隨機的。

2) no-loop防止死循環

在一個規則中如果條件滿足就對Working Memory當中的某個Fact對象進行修改，比如使用update將其更新到當前的Working Memory當中，這時候引擎會再次檢查所有的規則是否滿足條件，如果滿足會再執行，可能會出現死循環

作用：用來控制已經執行過的規則條件再次滿足時是否再次執行，默認是false，如果屬性值是true，表示該規則只會被規則引擎檢查一次，如果滿足條件就執行規則的RHS部分。

3)引擎內部因爲對Fact更新引起引擎再次啓動檢查規則，那麼它會忽略掉所有的no-loop屬性設置爲true的規則,造成死循環。

問題：案例"DECLINE STAY"與"do not audit"在對Fact更新引起引擎再次啓動檢查規則,造成死循環。

排查方法：

1)top:查看機器性能,找到java進程號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進程中各個線程情況，找到佔用cpu最高的java線程號

[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 :輸出各個線程執行到哪個方法導致的CPU飆升
vi /tmp/ pid-30533.txt 內容如下：

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