version: v1beta1type: flowtimeoutSeconds: 3600steps:  - type: task    name: generateInfo    timeoutSeconds: 300    resourceArn: acs:mns:::/topics/generateInfo-fnf-demo-jiyuan/messages    pattern: waitForCallback    inputMappings:      - target: taskToken        source: $context.task.token      - target: products        source: $input.products      - target: supplier        source: $input.supplier      - target: address        source: $input.address      - target: orderNum        source: $input.orderNum      - target: type        source: $context.step.name    outputMappings:      - target: paymentcombination        source: $local.paymentcombination      - target: orderNum        source: $local.orderNum    serviceParams:      MessageBody: $      Priority: 1    catch:      - errors:          - FnF.TaskTimeout        goto: orderCanceled  -type: task    name: payment    timeoutSeconds: 300    resourceArn: acs:mns:::/topics/payment-fnf-demo-jiyuan/messages    pattern: waitForCallback    inputMappings:      - target: taskToken        source: $context.task.token      - target: orderNum        source: $local.orderNum      - target: paymentcombination        source: $local.paymentcombination      - target: type        source: $context.step.name    outputMappings:      - target: paymentMethod        source: $local.paymentMethod      - target: orderNum        source: $local.orderNum      - target: price        source: $local.price      - target: taskToken        source: $input.taskToken    serviceParams:      MessageBody: $      Priority: 1    catch:      - errors:          - FnF.TaskTimeout        goto: orderCanceled  - type: choice    name: paymentCombination    inputMappings:      - target: orderNum        source: $local.orderNum      - target: paymentMethod        source: $local.paymentMethod      - target: price        source: $local.price      - target: taskToken        source: $local.taskToken    choices:      - condition: $.paymentMethod == "zhifubao"        steps:          - type: task            name: zhifubao            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan/functions/zhifubao-fnf-demo            inputMappings:              - target: price                source: $input.price                          - target: orderNum                source: $input.orderNum              - target: paymentMethod                source: $input.paymentMethod              - target: taskToken                source: $input.taskToken      - condition: $.paymentMethod == "weixin"        steps:          - type: task            name: weixin            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/weixin-fnf-demo            inputMappings:            - target: price              source: $input.price                        - target: orderNum              source: $input.orderNum            - target: paymentMethod              source: $input.paymentMethod            - target: taskToken              source: $input.taskToken      - condition: $.paymentMethod == "unionpay"        steps:          - type: task            name: unionpay            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/union-fnf-demo            inputMappings:            - target: price              source: $input.price                        - target: orderNum              source: $input.orderNum            - target: paymentMethod              source: $input.paymentMethod            - target: taskToken              source: $input.taskToken    default:      goto: orderCanceled  - type: task    name: orderCompleted    resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/orderCompleted    end: true  - type: task    name: orderCanceled    resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/cancerOrder

<dependency>    <groupId>com.aliyun</groupId>    <artifactId>aliyun-java-sdk-core</artifactId>    <version>[4.3.2,5.0.0)</version></dependency><dependency>    <groupId>com.aliyun</groupId>    <artifactId>aliyun-java-sdk-fnf</artifactId>    <version>[1.0.0,5.0.0)</version></dependency>

@Configurationpublic class FNFConfig {
    @Bean    public IAcsClient createDefaultAcsClient(){        DefaultProfile profile = DefaultProfile.getProfile(                "cn-xxx",          // 地域ID                "ak",      // RAM 账号的AccessKey ID                "sk"); // RAM 账号Access Key Secret        IAcsClient client = new DefaultAcsClient(profile);        return client;    }
}

   @GetMapping("/startFNF/{fnfname}/{execuname}/{input}")    public StartExecutionResponse startFNF(@PathVariable("fnfname") String fnfName,                                           @PathVariable("execuname") String execuName,                                           @PathVariable("input") String inputStr) throws ClientException {        JSONObject jsonObject = new JSONObject();        jsonObject.put("fnfname", fnfName);        jsonObject.put("execuname", execuName);        jsonObject.put("input", inputStr);        return fnfService.startFNF(jsonObject);    }

    @Override    public StartExecutionResponse startFNF(JSONObject jsonObject) throws ClientException {        StartExecutionRequest request = new StartExecutionRequest();        String orderNum = jsonObject.getString("execuname");        request.setFlowName(jsonObject.getString("fnfname"));        request.setExecutionName(orderNum);        request.setInput(jsonObject.getString("input"));
        JSONObject inputObj = jsonObject.getJSONObject("input");        Order order = new Order();        order.setOrderNum(orderNum);        order.setAddress(inputObj.getString("address"));        order.setProducts(inputObj.getString("products"));        order.setSupplier(inputObj.getString("supplier"));        orderMap.put(orderNum, order);
        return iAcsClient.getAcsResponse(request);    }

            submitOrder(){                const orderNum = uuid.v1()                this.$axios.$get('/startFNF/OrderDemo-Jiyuan/'+orderNum+'/{\n' +                    '  "products": "'+this.products+'",\n' +                    '  "supplier": "'+this.supplier+'",\n' +                    '  "orderNum": "'+orderNum+'",\n' +                    '  "address": "'+this.address+'"\n' +                    '}' ).then((response) => {                    console.log(response)                    if(response.message == "success"){                        this.$router.push('/orderdemo/' + orderNum)                    }                })            }

  - type: task    name: generateInfo    timeoutSeconds: 300    resourceArn: acs:mns:::/topics/generateInfo-fnf-demo-jiyuan/messages    pattern: waitForCallback    inputMappings:      - target: taskToken        source: $context.task.token      - target: products        source: $input.products      - target: supplier        source: $input.supplier      - target: address        source: $input.address      - target: orderNum        source: $input.orderNum      - target: type        source: $context.step.name    outputMappings:      - target: paymentcombination        source: $local.paymentcombination      - target: orderNum        source: $local.orderNum    serviceParams:      MessageBody: $      Priority: 1    catch:      - errors:          - FnF.TaskTimeout        goto: orderCanceled```
- name：节点名称。
- timeoutSeconds：超时时间。该节点等待的时长，超过时间后会跳转到 goto 分支指向的 orderCanceled 节点。
- pattern：设置为 waitForCallback，表示需要等待确认。inputMappings：该节点入参。
   - taskToken：Serverless 工作流自动生成的 Token。   - products：选择的商品。   - supplier：选择的商家。   - address：送餐地址。   - orderNum：订单号。- outputMappings：该节点的出参。
   - paymentcombination：该商家支持的支付方式。   - orderNum：订单号。- catch：捕获异常，跳转到其他分支。
这里 resourceArn 和 serviceParams 需要拿出来单独解释。Serverless 工作流支持与多个云服务集成，即：将其他服务作为任务步骤的执行单元。服务集成方式由 FDL 语言表达，在任务步骤中，可以使用 resourceArn 来定义集成的目标服务，使用 pattern 定义集成模式。所以可以看到在 resourceArn 中配置 acs:mns:::/topics/generateInfo-fnf-demo-jiyuan/messages 信息，即在 generateInfo 节点中集成了 MNS 消息队列服务，当 generateInfo 节点触发后会向 generateInfo-fnf-demo-jiyuanTopic 中发送一条消息。那么消息正文和参数则在 serviceParams 对象中指定。MessageBody 是消息正文，配置 $ 表示通过输入映射 inputMappings 产生消息正文。
看完第一个节点的示例，大家可以看到，在 Serverless 工作流中，节点之间的信息传递可以通过集成 MNS 发送消息来传递，也是使用比较广泛的方式之一。
## 4. generateInfo-fnf-demo 函数
向 generateInfo-fnf-demo-jiyuanTopic 中发送的这条消息包含了商品信息、商家信息、地址、订单号，表示一个下订单流程的开始，既然有发消息，那么必然有接受消息进行后续处理。所以打开函数计算控制台，创建服务，在服务下创建名为 generateInfo-fnf-demo 的事件触发器函数，这里选择 Python Runtime：
![8.png](https://ucc.alicdn.com/pic/developer-ecology/291e93740e48446197f29aa179a5f7cb.png)
创建 MNS 触发器，选择监听 generateInfo-fnf-demo-jiyuanTopic。
![9.png](https://ucc.alicdn.com/pic/developer-ecology/880c91561a6747d59c29bb7894eb727a.png)
打开消息服务 MNS 控制台，创建 generateInfo-fnf-demo-jiyuanTopic：
![10.png](https://ucc.alicdn.com/pic/developer-ecology/e9ab6266f1f046e08a78b9144c797db0.png)
做好函数的准备工作，我们来开始写代码：

region = "cn-hangzhou"account_id = "XXXX"ak_id = "XXX"ak_secret = "XXX"fnf_client = AcsClient(    ak_id,    ak_secret,    region)logger = logging.getLogger()# 2. event内的信息即接受到Topic generateInfo-fnf-demo-jiyuan中的消息内容，将其转换为Json对象bodyJson = json.loads(event)logger.info("products:" + bodyJson["products"])logger.info("supplier:" + bodyJson["supplier"])logger.info("address:" + bodyJson["address"])logger.info("taskToken:" + bodyJson["taskToken"])supplier = bodyJson["supplier"]taskToken = bodyJson["taskToken"]orderNum = bodyJson["orderNum"]# 3. 判断什么商家使用什么样的支付方式组合，这里的示例比较简单粗暴，正常情况下，应该使用元数据配置的方式获取paymentcombination = ""if supplier == "haidilao":    paymentcombination = "zhifubao,weixin"else:    paymentcombination = "zhifubao,weixin,unionpay"
# 4. 调用Java服务暴露的接口，更新订单信息，主要是更新支付方式url = "http://xx.xx.xx.xx:8080/setPaymentCombination/" + orderNum + "/" + paymentcombination + "/0"x = requests.get(url)
# 5. 给予generateInfo节点响应，并返回数据，这里返回了订单号和支付方式output = "{\"orderNum\": \"%s\", \"paymentcombination\":\"%s\" " \                     "}" % (orderNum, paymentcombination)request = ReportTaskSucceededRequest.ReportTaskSucceededRequest()request.set_Output(output)request.set_TaskToken(taskToken)resp = fnf_client.do_action_with_exception(request)return 'hello world'

因为 generateInfo-fnf-demo 函数配置了 MNS 触发器，所以当 TopicgenerateInfo-fnf-demo-jiyuan 有消息后就会触发执行 generateInfo-fnf-demo 函数。
整个代码分五部分：
- 构建 Serverless 工作流 Client。
- event 内的信息即接受到 TopicgenerateInfo-fnf-demo-jiyuan 中的消息内容，将其转换为 Json 对象。
- 判断什么商家使用什么样的支付方式组合，这里的示例比较简单粗暴，正常情况下，应该使用元数据配置的方式获取。比如在系统内有商家信息的配置功能，通过在界面上配置该商家支持哪些支付方式，形成元数据配置信息，提供查询接口，在这里进行查询。
- 调用 Java 服务暴露的接口，更新订单信息，主要是更新支付方式。
- 给予 generateInfo 节点响应，并返回数据，这里返回了订单号和支付方式。因为该节点的 pattern 是 waitForCallback，所以需要等待响应结果。
## 5. payment 节点
我们再来看第二个节点 payment，先来看 FDL 代码：

# -*- coding: utf-8 -*-import loggingimport jsonimport osimport timeimport loggingfrom aliyunsdkcore.client import AcsClientfrom aliyunsdkcore.acs_exception.exceptions import ServerExceptionfrom aliyunsdkcore.client import AcsClientfrom aliyunsdkfnf.request.v20190315 import ReportTaskSucceededRequestfrom aliyunsdkfnf.request.v20190315 import ReportTaskFailedRequestfrom mns.account import Account  # pip install aliyun-mnsfrom mns.queue import *
def handler(event, context):    logger = logging.getLogger()    region = "xxx"    account_id = "xxx"    ak_id = "xxx"    ak_secret = "xxx"    mns_endpoint = "http://your_account_id.mns.cn-hangzhou.aliyuncs.com/"    queue_name = "payment-queue-fnf-demo"    my_account = Account(mns_endpoint, ak_id, ak_secret)    my_queue = my_account.get_queue(queue_name)    # my_queue.set_encoding(False)    fnf_client = AcsClient(        ak_id,        ak_secret,        region    )    eventJson = json.loads(event)
    isLoop = True    while isLoop:        try:            recv_msg = my_queue.receive_message(30)            isLoop = False            # body = json.loads(recv_msg.message_body)            logger.info("recv_msg.message_body:======================" + recv_msg.message_body)            msgJson = json.loads(recv_msg.message_body)            my_queue.delete_message(recv_msg.receipt_handle)            # orderCode = int(time.time())            task_token = eventJson["taskToken"]            orderNum = eventJson["orderNum"]            output = "{\"orderNum\": \"%s\", \"paymentMethod\": \"%s\", \"price\": \"%s\" " \                         "}" % (orderNum, msgJson["paymentMethod"], msgJson["price"])            request = ReportTaskSucceededRequest.ReportTaskSucceededRequest()            request.set_Output(output)            request.set_TaskToken(task_token)            resp = fnf_client.do_action_with_exception(request)        except Exception as e:            logger.info("new loop")    return 'hello world'

# -*- coding: utf-8 -*-
import loggingimport urllib.parseimport jsonfrom mns.account import Account  # pip install aliyun-mnsfrom mns.queue import *HELLO_WORLD = b'Hello world!\n'
def handler(environ, start_response):    logger = logging.getLogger()     context = environ['fc.context']    request_uri = environ['fc.request_uri']    for k, v in environ.items():      if k.startswith('HTTP_'):        # process custom request headers        pass    try:               request_body_size = int(environ.get('CONTENT_LENGTH', 0))       except (ValueError):               request_body_size = 0      request_body = environ['wsgi.input'].read(request_body_size)     paymentMethod = urllib.parse.unquote(request_body.decode("GBK"))    logger.info(paymentMethod)    paymentMethodJson = json.loads(paymentMethod)
    region = "cn-xxx"    account_id = "xxx"    ak_id = "xxx"    ak_secret = "xxx"    mns_endpoint = "http://your_account_id.mns.cn-hangzhou.aliyuncs.com/"    queue_name = "payment-queue-fnf-demo"    my_account = Account(mns_endpoint, ak_id, ak_secret)    my_queue = my_account.get_queue(queue_name)    output = "{\"paymentMethod\": \"%s\", \"price\":\"%s\" " \                         "}" % (paymentMethodJson["paymentMethod"], paymentMethodJson["price"])    msg = Message(output)    my_queue.send_message(msg)
    status = '200 OK'    response_headers = [('Content-type', 'text/plain')]    start_response(status, response_headers)    return [HELLO_WORLD]

- type: choice    name: paymentCombination    inputMappings:      - target: orderNum        source: $local.orderNum      - target: paymentMethod        source: $local.paymentMethod      - target: price        source: $local.price      - target: taskToken        source: $local.taskToken    choices:      - condition: $.paymentMethod == "zhifubao"        steps:          - type: task            name: zhifubao            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan/functions/zhifubao-fnf-demo            inputMappings:              - target: price                source: $input.price                          - target: orderNum                source: $input.orderNum              - target: paymentMethod                source: $input.paymentMethod              - target: taskToken                source: $input.taskToken      - condition: $.paymentMethod == "weixin"        steps:          - type: task            name: weixin            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/weixin-fnf-demo            inputMappings:            - target: price              source: $input.price                        - target: orderNum              source: $input.orderNum            - target: paymentMethod              source: $input.paymentMethod            - target: taskToken              source: $input.taskToken      - condition: $.paymentMethod == "unionpay"        steps:          - type: task            name: unionpay            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan.LATEST/functions/union-fnf-demo            inputMappings:            - target: price              source: $input.price                        - target: orderNum              source: $input.orderNum            - target: paymentMethod              source: $input.paymentMethod            - target: taskToken              source: $input.taskToken    default:      goto: orderCanceled

    choices:      - condition: $.paymentMethod == "zhifubao"        steps:          - type: task            name: zhifubao            resourceArn: acs:fc:cn-hangzhou:your_account_id:services/FNFDemo-jiyuan/functions/zhifubao-fnf-demo            inputMappings:              - target: price                source: $input.price                          - target: orderNum                source: $input.orderNum              - target: paymentMethod                source: $input.paymentMethod              - target: taskToken                source: $input.taskToken

# -*- coding: utf-8 -*-import loggingimport jsonimport requestsimport urllib.parsefrom aliyunsdkcore.client import AcsClientfrom aliyunsdkcore.acs_exception.exceptions import ServerExceptionfrom aliyunsdkfnf.request.v20190315 import ReportTaskSucceededRequestfrom aliyunsdkfnf.request.v20190315 import ReportTaskFailedRequest
def handler(event, context):  region = "cn-xxx"  account_id = "xxx"  ak_id = "xxx"  ak_secret = "xxx"  fnf_client = AcsClient(    ak_id,    ak_secret,    region  )  logger = logging.getLogger()  logger.info(event)  bodyJson = json.loads(event)  price = bodyJson["price"]  taskToken = bodyJson["taskToken"]  orderNum = bodyJson["orderNum"]  paymentMethod = bodyJson["paymentMethod"]  logger.info("price:" + price)  newPrice = int(price) * 0.8  logger.info("newPrice:" + str(newPrice))  url = "http://xx.xx.xx.xx:8080/setPaymentCombination/" + orderNum + "/" + paymentMethod + "/" + str(newPrice)  x = requests.get(url)
  return {"Status":"ok"}