開源、強大的工作流引擎：camunda入門介紹

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簡介

Camunda is a Java-based framework supporting BPMN for workflow and process automation, CMMN for Case Management and DMN for Business Decision Management.

重要概念

• BPMN - Business Process Model and Notation (BPMN) is a standard for Workflow and Process Automation. Camunda supports the 2.0 version of BPMN.
• https://docs.camunda.org/get-started/bpmn20/
• CMMN - Case Management Model and Notation (CMMN) is a standard for Case Management. Camunda supports the 1.1 version of CMMN.
• https://docs.camunda.org/get-started/cmmn11/
• DMN - Decision Model and Notation (DMN) is a standard for Business Decision Management. Camunda supports the 1.1 version of DMN.
• https://docs.camunda.org/get-started/dmn11/

工作流對比

關鍵人物介紹

Tom Baeyens - 創建了jbpm。離開JBoss後，jBPM的下一個版本jBPM5完全放棄了jBPM4的基礎代碼，基於Drools Flow重頭來過，目前官網已經推出了jBPM6的beta版本；Tom Baeyens加入Alfresco後很快推出了新的基於jBPM4的開源工作流系統Activiti。2012年末，Alfresco的Activity BPM 小組正經歷一系列的轉變：Tom Baeyens將不再領導Activity工程，決定離開Alfresco。camunda是Activity最大的貢獻者之一（除Alfresco以外），同時也是它一個主要的執行諮詢合作夥伴。camunda表示Activity可能太拘束於Alfresco對以文檔為中心的工作流的需求，而忽視了Activity起步時的更為普遍的BPM平台，故而從Activiti分支建立了camunda BPM項目。

框架總覽

流程引擎架構

框架示例

Camunda Tomcat 集成容器下載:

• https://camunda.org/download/

解壓tomcat，切換到目錄server\apache-tomcat-8.0.24\webapps，包含以下子目錄：

•Camunda -- 管理功能模塊，包含admin、cockpit、tasklist

•camunda-invoice – 發票審批demo

•engine-rest – 工作流程引擎Rest API模塊

•Examples – 其他demo例子

數據庫創建:

切換目錄sql\create\選擇對應sql腳本執行

tomcat配置修改:

切換到server\apache-tomcat-8.0.24\conf\目錄

bpm-platform.xml

camunda自有配置維護文件。

可根據具體應用場景修改以下全局配置屬性

<properties>

<property name="history">full</property>

<property name="databaseSchemaUpdate">true</property>

<property name="authorizationEnabled">true</property>

<property name="jobExecutorActivate">true</property>

<property name="jobExecutorDeploymentAware">true</property>

</properties>

tomcat配置修改:

切換到server\apache-tomcat-8.0.24\conf\目錄

server.xml

tomcat容器管理配置維護文件。

<Resource name="jdbc/ProcessEngine"

auth="Container"

type="javax.sql.DataSource"

factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"

uniqueResourceName="process-engine"

driverClassName="oracle.jdbc.driver.OracleDriver"

url="jdbc:oracle:thin:@127.0.0.1:1521:camunda"

defaultTransactionIsolation="READ_COMMITTED"

username="camunda"

password="123456"

maxActive="20"

minIdle="5"

removeAbandoned="true"

removeAbandonedTimeout="60"

testOnBorrow="true"

validationQuery="select count(1) from dual"

logAbandoned="true"/>

應用集成

添加依賴包

compile 'org.camunda.bpm:camunda-engine:7.7.0'

compile 'org.camunda.bpm:camunda-engine-spring:7.7.0'

添加spring bean

<bean id="camundaTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
 <property name="dataSource" ref="dataSource" />
</bean>
<bean id="processEngineConfiguration" class="org.camunda.bpm.engine.spring.SpringProcessEngineConfiguration">
 <property name="processEngineName" value="engine" />
 <property name="historyLevel" value="HISTORY_LEVEL_FULL"/>
 <property name="jobExecutorDeploymentAware" value="true"/>
 <property name="dataSource" ref="dataSource" />
 <property name="transactionManager" ref="camundaTransactionManager" />
 <property name="databaseSchemaUpdate" value="true" />
 <property name="jobExecutorActivate" value="true" />
 <property name="deploymentResources" value="classpath:*.bpmn" />
</bean>
<bean id="processEngine" class="org.camunda.bpm.engine.spring.ProcessEngineFactoryBean">
 <property name="processEngineConfiguration" ref="processEngineConfiguration" />
</bean>
<bean id="repositoryService" factory-bean="processEngine" factory-method="getRepositoryService" />
<bean id="runtimeService" factory-bean="processEngine" factory-method="getRuntimeService" />
<bean id="taskService" factory-bean="processEngine" factory-method="getTaskService" />
<bean id="historyService" factory-bean="processEngine" factory-method="getHistoryService" />
<bean id="managementService" factory-bean="processEngine" factory-method="getManagementService" /> 

modeler流程文件

將modeler設計流程模板放到應用工程resources目錄或者子目錄下。

用戶集成方式

Camunda自有user體系

優：無需改動

缺：靈活性差，運維成本高

使用ldap用戶集成

優：可和支持ldap功能對接

缺：依賴ldap功能限制

通過插件擴展用戶體系

優：通過擴展能實現定製化需求

缺：對camunda熟悉，開發成本高

只使用workflow節點流轉功能

優：應用靈活，可滿足不同業務需求

缺：camunda部分豐富功能無法使用，可能重新開發框架存在組件

Job Executor

文檔地址:https://docs.camunda.org/manual/7.7/user-guide/process-engine/the-job-executor/

Job 激活配置:<property name="jobExecutorActivate" value="true" />

job 工作架構：

同構集群部署：

異構集群部署：

支持異構集群部署，部署node設置jobExecutorDeploymentAware=true

<property name="jobExecutorDeploymentAware">true</property>

附錄

• engine-rest api
• https://docs.camunda.org/manual/7.7/reference/rest/
• Web modeler
• http://bpmn.io/toolkit/bpmn-js/walkthrough/
• camunda get-started
• https://docs.camunda.org/get-started/
• Camunda Guid
• https://docs.camunda.org/manual/7.7/introduction/
• LDAP Identity Service
• https://docs.camunda.org/manual/7.7/user-guide/process-engine/identity-service/