Help Center/ FunctionGraph/ API Reference/ APIs/ Flows/ Executing a Flow Asynchronously
Updated on 2026-10-27 GMT+08:00

Executing a Flow Asynchronously

Function

This API is used to execute a flow asynchronously. It is available only in the Chinese mainland regions.

Calling Method

For details, see Calling APIs.

Authorization Information

Each account has all the permissions required to call all APIs, but IAM users must be assigned the required permissions. For details about the required permissions, see Permissions Policies and Supported Actions.

URI

POST /v2/{project_id}/fgs/workflows/{workflow_id}/executions

Table 1 Path Parameters

Parameter

Mandatory

Type

Description

project_id

Yes

String

Definition

Project ID. For details, see Obtaining a Project ID.

Constraints

N/A

Range

The value contains 32 characters. Only letters and digits are allowed.

Default Value

N/A

workflow_id

Yes

String

Definition

Flow ID.

Constraints

N/A

Range

The value contains 32 characters. Only letters and digits are allowed.

Default Value

N/A

Request Parameters

Table 2 Request header parameters

Parameter

Mandatory

Type

Description

X-Create-Time

No

String

Definition

Time when a function flow task was created.

Constraints

Format: yyyy-MM-dd.

Range

The value must be earlier than or equal to the current time.

Default Value

N/A

X-WorkflowRun-ID

No

String

Definition

Function flow task ID.

Constraints

N/A

Range

The value contains 32 characters. Only letters and digits are allowed.

Default Value

N/A

X-WorkflowRun-MergeFnParameters

No

String

Definition

Whether the function flow task combines the output of the previous node and the input of the next node into one input.

Constraints

N/A

Range

true, false, or not specified

Default Value

N/A

Table 3 Request body parameters

Parameter

Mandatory

Type

Description

headers

No

Object

Definition

Headers for flow execution.

Constraints

N/A

Range

N/A

Default Value

N/A

input

Yes

Object

Definition

Input parameters for flow execution. You can use JSONPath for parameter mapping and specify a default value.

Constraints

N/A

Range

N/A

Default Value

N/A

Response Parameters

Status code: 200

Table 4 Response body parameters

Parameter

Type

Description

execution_id

String

Definition

Function flow asynchronous task ID

Range

N/A

Status code: 400

Table 5 Response body parameters

Parameter

Type

Description

error_code

String

Error code.

error_msg

String

Error description.

Status code: 404

Table 6 Response body parameters

Parameter

Type

Description

error_code

String

Error code.

error_msg

String

Error description.

Status code: 500

Table 7 Response body parameters

Parameter

Type

Description

error_code

String

Error code.

error_msg

String

Error description.

Example Requests

Execute a flow.

POST /v2/{project_id}/fgs/workflows/{workflow_id}/executions

{
  "headers" : {
    "tenantId" : "user1"
  },
  "input" : {
    "arg1" : "argument_1",
    "arg2" : "argument_2"
  }
}

Example Responses

Status code: 200

{
  "execution_id" : "48aff955-ea10-4ffd-b426-190bc192dc14"
}

SDK Sample Code

The SDK sample code is as follows.

Java

Execute a flow.

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package com.huaweicloud.sdk.test;

import com.huaweicloud.sdk.core.auth.ICredential;
import com.huaweicloud.sdk.core.auth.BasicCredentials;
import com.huaweicloud.sdk.core.exception.ConnectionException;
import com.huaweicloud.sdk.core.exception.RequestTimeoutException;
import com.huaweicloud.sdk.core.exception.ServiceResponseException;
import com.huaweicloud.sdk.functiongraph.v2.region.FunctionGraphRegion;
import com.huaweicloud.sdk.functiongraph.v2.*;
import com.huaweicloud.sdk.functiongraph.v2.model.*;


public class StartWorkflowExecutionSolution {

    public static void main(String[] args) {
        // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
        // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
        String ak = System.getenv("CLOUD_SDK_AK");
        String sk = System.getenv("CLOUD_SDK_SK");
        String projectId = "{project_id}";

        ICredential auth = new BasicCredentials()
                .withProjectId(projectId)
                .withAk(ak)
                .withSk(sk);

        FunctionGraphClient client = FunctionGraphClient.newBuilder()
                .withCredential(auth)
                .withRegion(FunctionGraphRegion.valueOf("<YOUR REGION>"))
                .build();
        StartWorkflowExecutionRequest request = new StartWorkflowExecutionRequest();
        request.withWorkflowId("{workflow_id}");
        FlowExecuteBody body = new FlowExecuteBody();
        body.withInput("{\"arg2\":\"argument_2\",\"arg1\":\"argument_1\"}");
        body.withHeaders("{\"tenantId\":\"user1\"}");
        request.withBody(body);
        try {
            StartWorkflowExecutionResponse response = client.startWorkflowExecution(request);
            System.out.println(response.toString());
        } catch (ConnectionException e) {
            e.printStackTrace();
        } catch (RequestTimeoutException e) {
            e.printStackTrace();
        } catch (ServiceResponseException e) {
            e.printStackTrace();
            System.out.println(e.getHttpStatusCode());
            System.out.println(e.getRequestId());
            System.out.println(e.getErrorCode());
            System.out.println(e.getErrorMsg());
        }
    }
}

Python

Execute a flow.

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# coding: utf-8

import os
from huaweicloudsdkcore.auth.credentials import BasicCredentials
from huaweicloudsdkfunctiongraph.v2.region.functiongraph_region import FunctionGraphRegion
from huaweicloudsdkcore.exceptions import exceptions
from huaweicloudsdkfunctiongraph.v2 import *

if __name__ == "__main__":
    # The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
    # In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
    ak = os.environ["CLOUD_SDK_AK"]
    sk = os.environ["CLOUD_SDK_SK"]
    projectId = "{project_id}"

    credentials = BasicCredentials(ak, sk, projectId)

    client = FunctionGraphClient.new_builder() \
        .with_credentials(credentials) \
        .with_region(FunctionGraphRegion.value_of("<YOUR REGION>")) \
        .build()

    try:
        request = StartWorkflowExecutionRequest()
        request.workflow_id = "{workflow_id}"
        request.body = FlowExecuteBody(
            input="{\"arg2\":\"argument_2\",\"arg1\":\"argument_1\"}",
            headers="{\"tenantId\":\"user1\"}"
        )
        response = client.start_workflow_execution(request)
        print(response)
    except exceptions.ClientRequestException as e:
        print(e.status_code)
        print(e.request_id)
        print(e.error_code)
        print(e.error_msg)

Go

Execute a flow.

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package main

import (
	"fmt"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/core/auth/basic"
    functiongraph "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/functiongraph/v2"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/services/functiongraph/v2/model"
    region "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/functiongraph/v2/region"
)

func main() {
    // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
    // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
    ak := os.Getenv("CLOUD_SDK_AK")
    sk := os.Getenv("CLOUD_SDK_SK")
    projectId := "{project_id}"

    auth, err := basic.NewCredentialsBuilder().
        WithAk(ak).
        WithSk(sk).
        WithProjectId(projectId).
        SafeBuild()

    if err != nil {
        fmt.Println(err)
        return
    }

    hcClient, err := functiongraph.FunctionGraphClientBuilder().
         WithRegion(region.ValueOf("<YOUR REGION>")).
         WithCredential(auth).
         SafeBuild()


    if err != nil {
        fmt.Println(err)
        return
    }

    client := functiongraph.NewFunctionGraphClient(hcClient)

    request := &model.StartWorkflowExecutionRequest{}
	request.WorkflowId = "{workflow_id}"
	var inputFlowExecuteBody interface{} = "{\"arg2\":\"argument_2\",\"arg1\":\"argument_1\"}"
	var headersFlowExecuteBody interface{} = "{\"tenantId\":\"user1\"}"
	request.Body = &model.FlowExecuteBody{
		Input: &inputFlowExecuteBody,
		Headers: &headersFlowExecuteBody,
	}
	response, err := client.StartWorkflowExecution(request)
	if err == nil {
        fmt.Printf("%+v\n", response)
    } else {
        fmt.Println(err)
    }
}

More

For SDK sample code of more programming languages, see the Sample Code tab in API Explorer. SDK sample code can be automatically generated.

Status Codes

Status Code

Description

200

Success

400

Bad Request

404

Bad Request

500

Internal Server Error

Error Codes

See Error Codes.