How CloudFlow integrates with Simple Message Queue (formerly MNS)-CloudFlow(CloudFlow)-阿里云帮助中心

CloudFlow integrates with Simple Message Queue (formerly MNS) (SMQ) to send messages to queues and topics directly from a workflow. Use the MNS:SendMessage action in your flow definition to deliver messages with optional priority, delay, and email or SMS attributes.

Sample flow definition

The following flow definition sends a message to an SMQ queue with custom priority, a 10-second delay, and email and SMS attributes:

Type: StateMachine
Name: MyWorkflow
SpecVersion: v1
StartAt: SendMessage
States:
  - Type: Task
    Name: SendMessage
    Action: MNS:SendMessage
    TaskMode: RequestComplete
    Description: Send a message to an SMQ queue
    Parameters:
      resourceArn: acs:mns:cn-hangzhou:1231231****:/queues/fnf-mns-queues/messages
      message:
        body: ok
      priority: 1
      delaySeconds: 10
      messageTag: aaa
      messageAttributes:
        MailAttributes:
          Subject: subject
          AccountName: account
          AddressType: 123
          IsHTML: true
          ReplyToAddress: 456
        SMSAttributes:
          FreeSignName: test-free-sign-name
          TemplateCode: test-template-code
          Type: test-type
          Receiver: test-receiver
          SmsParams: test-sms-params
    End: true

Notable fields:

Action: Set to MNS:SendMessage.
TaskMode: Set to RequestComplete or WaitForCustomCallback. For details, see Execution modes.
Name and Description: Values that describe the task in your workflow.

Parameters

Parameter	Required	Description	Example
resourceArn	Yes	Alibaba Cloud Resource Name (ARN) of the SMQ queue or topic.	`acs:mns:cn-hangzhou:1231231****:/queues/fnf-mns-queues/messages`
message	Yes	Message body. Accepts plain text, a structured object, or an array. Structured objects and arrays are automatically converted to JSON before sending.	`This is a test message`
priority	No	Message priority. Valid values: 1 to 16. A smaller value indicates higher priority. Default: 8.	`8`
delaySeconds	No	Seconds to delay the message before it becomes consumable. Valid values: 0 to 604800. Default: 0.	`0`
messageTag	No	Message tag. Applies only to topic-type messages.	`tag`
messageAttributes	No	Additional message attributes for email or SMS delivery. See `messageAttributes` fields.	-

`messageAttributes` fields

The messageAttributes parameter supports email delivery through MailAttributes and SMS delivery through SMSAttributes.

MailAttributes

Field	Description
Subject	Email subject line.
AccountName	Sender account name.
AddressType	Address type identifier.
IsHTML	Whether the email body is in HTML format. Valid values: `true`, `false`.
ReplyToAddress	Reply-to address.

SMSAttributes

Field	Description
FreeSignName	SMS signature name.
TemplateCode	SMS template code.
Type	SMS type.
Receiver	SMS recipient.
SmsParams	SMS template parameters.

Example:

messageAttributes:
  MailAttributes:
    Subject: subject
    AccountName: account
    AddressType: 123
    IsHTML: true
    ReplyToAddress: 456
  SMSAttributes:
    FreeSignName: test-free-sign-name
    TemplateCode: test-template-code
    Type: test-type
    Receiver: test-receiver
    SmsParams: test-sms-params

Return value

A successful request returns a JSON object with the following fields:

Field	Description
MessageBodyMD5	MD5 hash of the message body.
MessageID	Unique identifier of the sent message.
ReceiptHandle	Receipt handle for the message.
RequestID	Unique identifier of the API request.

Example:

{
    "MessageBodyMD5": "74B87337454200D4D33F8**********",
    "MessageID": "02CCC72A80767FCE7FE97DDC**********",
    "ReceiptHandle": "",
    "RequestID": "65387E5A44383182**********"
}

Execution modes

The SMQ integration supports two execution modes that control when the task is considered complete. In both modes, after CloudFlow sends a message to SMQ, the task completes when the current HTTP request is complete, and the HTTP response is used as the task output.

Mode	Behavior	Use case
RequestComplete	Task completes immediately after the message is sent. The SMQ response becomes the task output.	Fire-and-forget messaging where no downstream acknowledgment is needed.
WaitForCustomCallback	Task pauses after the message is sent and waits for an external callback to resume.	Workflows that require external processing or human approval before continuing.

RequestComplete

After CloudFlow sends the message to SMQ, the task completes immediately. The SMQ response becomes the task output.

Set TaskMode to RequestComplete in the flow definition:

TaskMode: RequestComplete

WaitForCustomCallback

After CloudFlow sends the message to SMQ, the workflow pauses and waits for an external system to report the result. The workflow resumes only after the ReportTaskSucceeded or ReportTaskFailed API operation is called.

Set TaskMode to WaitForCustomCallback in the flow definition:

TaskMode: WaitForCustomCallback

Pass the task token to the external system

For the external system to call back into CloudFlow, it needs the task token. Include the token in the message by referencing $Context.Current.TaskToken in the data field:

- Type: Task
  Name: SendMessageWithCallback
  Action: MNS:SendMessage
  TaskMode: WaitForCustomCallback
  Parameters:
    resourceArn: acs:mns:cn-hangzhou:1231231****:/queues/fnf-mns-queues/messages
    message:
      body: ok
    data:
      key: $Context.Current.TaskToken
  End: true

Callback flow:

CloudFlow sends the message (including the task token) to the SMQ queue.
The external system consumes the message and extracts the task token from the data.key field.
After processing, the external system calls ReportTaskSucceeded or ReportTaskFailed with the task token to resume the workflow.