Zeebe服务学习1-简单部署与实现demo

1.Zeebe是什么？

Camunda公司研发的工作流引擎Zeebe，目标是对微服务的编排。具体详细介绍可以参考官网：https://zeebe.io/what-is-zeebe/

2.背景

随着微服务的发展，大家都单体服务进行了拆分，解耦，这样做引发了另外的一个问题：之前一个接口实现的功能，现在需要调用几个接口才能完成。如何解决这些原子性的接口呢？

这时候我们想到了Zeebe服务。

3.服务部署

  3.1 第一步：安装环境，不管你是Linux系统还是Win系统，首先需要安装上docker，因为我的机器是Win系统，本文就是介绍Windows系统下安装使用情况

  确保机器已经安装docker（没有安装的可以下载docker-win，进行安装）

3.2 第二步：在cmd里面执行命令：

docker run --name zeebe -p 26500:26500 camunda/zeebe:latest

　　至此，Zeebe服务已经安装成功了。

4.demo

4.1 第一步：创建一个控制台项目，这个应该都会

4.2 第二步：在项目中引用Zeebe客户端的nuget包，目前版本是0.11.0

4.3 第三步：建模，使用Zeebe Modeler工具进行建模

我需要实现的流程是：

 具体的BPMN代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:zeebe="http://camunda.org/schema/zeebe/1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" id="Definitions_1011qyd" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Zeebe Modeler" exporterVersion="0.6.2">
  <bpmn:process id="instock-process" name="instock-process" isExecutable="true">
    <bpmn:startEvent id="start" name="start">
      <bpmn:outgoing>SequenceFlow_instock</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:serviceTask id="createinstock" name="createinstock">
      <bpmn:extensionElements>
        <zeebe:taskDefinition type="createinstock" retries="3" />
        <zeebe:ioMapping>
          <zeebe:input source="InStockData" target="InStockData" />
        </zeebe:ioMapping>
      </bpmn:extensionElements>
      <bpmn:incoming>SequenceFlow_instock</bpmn:incoming>
      <bpmn:outgoing>SequenceFlow_modifystock</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:sequenceFlow id="SequenceFlow_instock" name="SequenceFlow_instock" sourceRef="start" targetRef="createinstock" />
    <bpmn:serviceTask id="modifystock" name="modifystock">
      <bpmn:extensionElements>
        <zeebe:taskDefinition type="modifystock" retries="3" />
        <zeebe:ioMapping>
          <zeebe:input source="StockData" target="StockData" />
        </zeebe:ioMapping>
      </bpmn:extensionElements>
      <bpmn:incoming>SequenceFlow_modifystock</bpmn:incoming>
      <bpmn:outgoing>SequenceFlow_gateway</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:sequenceFlow id="SequenceFlow_modifystock" name="SequenceFlow_modifystock" sourceRef="createinstock" targetRef="modifystock" />
    <bpmn:exclusiveGateway id="checknum" name="checknum">
      <bpmn:incoming>SequenceFlow_gateway</bpmn:incoming>
      <bpmn:outgoing>morethan300</bpmn:outgoing>
      <bpmn:outgoing>lessthan300</bpmn:outgoing>
    </bpmn:exclusiveGateway>
    <bpmn:sequenceFlow id="SequenceFlow_gateway" name="SequenceFlow_gateway" sourceRef="modifystock" targetRef="checknum" />
    <bpmn:serviceTask id="notify" name="notify">
      <bpmn:extensionElements>
        <zeebe:taskDefinition type="notify" retries="3" />
      </bpmn:extensionElements>
      <bpmn:incoming>morethan300</bpmn:incoming>
      <bpmn:outgoing>SequenceFlow_end</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:sequenceFlow id="morethan300" name="&#62;=300" sourceRef="checknum" targetRef="notify">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">stocknum&gt;=300</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:endEvent id="end" name="end">
      <bpmn:incoming>lessthan300</bpmn:incoming>
      <bpmn:incoming>SequenceFlow_end</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="lessthan300" name="lessthan300" sourceRef="checknum" targetRef="end">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">stocknum&lt;300</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:sequenceFlow id="SequenceFlow_end" name="SequenceFlow_end" sourceRef="notify" targetRef="end" />
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="instock-process">
      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="start">
        <dc:Bounds x="112" y="159" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="119" y="202" width="23" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="ServiceTask_0zssdcw_di" bpmnElement="createinstock">
        <dc:Bounds x="265" y="137" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="SequenceFlow_0yllvib_di" bpmnElement="SequenceFlow_instock">
        <di:waypoint x="148" y="177" />
        <di:waypoint x="265" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="163" y="159" width="88" height="27" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="ServiceTask_1db0jmn_di" bpmnElement="modifystock">
        <dc:Bounds x="481" y="137" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="SequenceFlow_1uaplin_di" bpmnElement="SequenceFlow_modifystock">
        <di:waypoint x="365" y="177" />
        <di:waypoint x="481" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="383" y="159" width="80" height="27" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="ExclusiveGateway_1sjnk3d_di" bpmnElement="checknum" isMarkerVisible="true">
        <dc:Bounds x="723" y="152" width="50" height="50" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="722" y="128" width="51" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="SequenceFlow_1hhfiqd_di" bpmnElement="SequenceFlow_gateway">
        <di:waypoint x="581" y="177" />
        <di:waypoint x="723" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="610" y="159" width="85" height="27" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="ServiceTask_016w4wa_di" bpmnElement="notify">
        <dc:Bounds x="954" y="319" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="SequenceFlow_1ffqddr_di" bpmnElement="morethan300">
        <di:waypoint x="748" y="202" />
        <di:waypoint x="748" y="359" />
        <di:waypoint x="954" y="359" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="839" y="341" width="32" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="EndEvent_01b3gni_di" bpmnElement="end">
        <dc:Bounds x="1208" y="159" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="1217" y="202" width="19" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="SequenceFlow_00imkpl_di" bpmnElement="lessthan300">
        <di:waypoint x="773" y="177" />
        <di:waypoint x="1208" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="961" y="159" width="60" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="SequenceFlow_0c9jvp6_di" bpmnElement="SequenceFlow_end">
        <di:waypoint x="1004" y="319" />
        <di:waypoint x="1004" y="177" />
        <di:waypoint x="1208" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="977" y="245" width="85" height="27" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

4.4 第四步：写代码

（1）客户端代码：

 internal class Program
    {
        private static readonly string DemoProcessPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Resources", "instock-process.bpmn");
        private static readonly string ZeebeUrl = "127.0.0.1:26500";
        private static dynamic WorkflowInstanceVariables = new
        {
            stocknum = 100
        };
        public static async Task Main(string[] args)
        {
            InitClient.Initialize();

            // create zeebe client
            var client = ZeebeClient.NewZeebeClient(ZeebeUrl);
            // deploy
            // var deployResponse = await client.NewDeployCommand().AddResourceFile(DemoProcessPath).Send();

            // create workflow instance
            // var workflowKey = deployResponse.Workflows[0].WorkflowKey;//2251799813685495
            // 模拟调用
            var workflowInstance = await client
                .NewCreateWorkflowInstanceCommand()
                .WorkflowKey(2251799813685495)
                .Variables(JsonConvert.SerializeObject(WorkflowInstanceVariables))
                .Send();

        }
｝

（2）服务端代码：

 internal class Program
    {
        private static Dictionary<string, string> JobTypeAndMethod = new Dictionary<string, string>()
        {
            { "createinstock","InStockJobHandler"},
            { "modifystock","StockJobHandler"},
            { "notify","NotifyJobHandler"}
        };
        private static readonly string ZeebeUrl = "127.0.0.1:26500";
        public static async Task Main(string[] args)
        {
            InitClient.Initialize();

            // create zeebe client
            var client = ZeebeClient.NewZeebeClient(ZeebeUrl);

            // open job worker
            await OpenJobWorkers(client);
        }

        private static Task OpenJobWorkers(IZeebeClient client)
        {
            
            using (var signal = new EventWaitHandle(false, EventResetMode.AutoReset))
            {
                foreach (var item in JobTypeAndMethod)
                {
                    client.NewWorker()
                        .JobType(item.Key)
                        .Handler(JobHandlerFactory.GetJobType(item.Value))
                        .MaxJobsActive(5)
                        .Name(item.Key)
                        .AutoCompletion()
                        .PollInterval(TimeSpan.FromSeconds(1))
                        .Timeout(TimeSpan.FromSeconds(10))
                        .Open();
                }
                // blocks main thread, so that worker can run
                signal.WaitOne();
            }
            return Task.CompletedTask;
        }

    }

客户端的代码中，只有第一次会将BPMN文件进行部署，Zeebe服务会返回一个Key，之后如果建模数据不发生改变的情况下，就可以直接使用key进行调用即可了，如果发生变化需要再一次部署才行；

每次部署都会改变工作流程的Version值（默认获取的事latestVersion）。

至此，一个简单的Zeebe Demo实现了。