带有 Step Function 的 AWS API 网关

Question

我想要一个将 AWS API Gateway 与 Step Function 集成的示例。我已阅读本教程 Creating a Step Functions API Using API Gateway 但该教程需要我以

格式发送请求

{    
"input": "{}",    
"name": "PostmanExecution",    
"stateMachineArn": "arn:aws:states:us-east-1:123456789012:stateMachine:Custom" 
}

我想发送正常的请求，并且只在 API Gateway 中配置这个 stateMachineArn，这样客户端就不需要发送这个了。

Answer 1

我设法通过使用 API Gateway 公开了 2 个端点，一个用于启动执行，第二个用于检查执行状态。

此操作无需使用 lambda，也无需通过参数指示步骤函数。

解决方案 CloudFormation 模板为：

AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31
Description: >
  The turtle calculator, a dummy slow calculator for comprehensive code example
Parameters:
  OpenAPIS3File:
    Description: '"openapi.yaml" file location'
    Default: ./openapi.yaml
    Type: String

Resources:
  Workflow:
    Type: AWS::StepFunctions::StateMachine
    Properties:
      StateMachineName: !Sub ${AWS::StackName}-state-machine
      RoleArn: !GetAtt StateExecutionRole.Arn
      DefinitionString: !Sub |
        {
          ...
        }

  Api:
    Type: AWS::Serverless::Api
    Properties:
      StageName: random-workflow
      Name: !Sub ${AWS::StackName}-api
      DefinitionBody:
        'Fn::Transform':
          Name: AWS::Include
          Parameters:
            Location: !Ref OpenAPIS3File

OpenAPI 配置是：

openapi: 3.0.1
info:
  title: Api Mocker
  description: Automated testing application for TGR
  contact:
    name: Patagonia-IT
    url: http://www.patagonia-it.com
    email: contacto@patagonia-it.com
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0.html
  version: 1.0.0

x-amazon-apigateway-request-validators:
  params:
    validateRequestParameters: true
    validateRequestBody: false

x-amazon-apigateway-request-validator: params

paths:
  /workflow:
    post:
      x-amazon-apigateway-integration:
        credentials:
          Fn::GetAtt: [ ApiGatewayStepFunctionsRole, Arn ]
        uri:
          Fn::Sub: arn:aws:apigateway:${AWS::Region}:states:action/StartExecution
        httpMethod: POST
        type: aws
        responses:
          default:
            statusCode: 200
            responseTemplates:
              application/json: |
                '{ "executionId": "$input.json('executionArn').split(':').get(7) }'
        requestTemplates:
          application/json:
            Fn::Sub: |-
              {
                "input": "$util.escapeJavaScript($input.json('$'))",
                "name": "$context.requestId",
                "stateMachineArn": "${Workflow}"
              }
      summary: Start workflow instance
      responses:
        200:
          $ref: '#/components/responses/200Execution'
        403:
          $ref: '#/components/responses/Error'
  /workflow/{executionId}:
    get:
      x-amazon-apigateway-integration:
        credentials:
          Fn::GetAtt: [ ApiGatewayStepFunctionsRole, Arn ]
        uri:
          Fn::Sub: arn:aws:apigateway:${AWS::Region}:states:action/DescribeExecution
        httpMethod: POST
        type: aws
        responses:
          default:
            statusCode: 200
            responseTemplates:
              application/json: |-
                #set ($status = $input.json('status'))
                {
                #if($status == '"SUCCEEDED"')
                  "output": $util.parseJson($input.json('output')),
                #end
                  "status": $status
                }
        requestTemplates:
          application/json:
            Fn::Sub: |-
              {
                "executionArn": "arn:aws:states:${AWS::Region}:${AWS::AccountId}:execution:${Workflow.Name}:$input.params().path.get('executionId')"
              }
      summary: Workflow execution status
      responses:
        200:
          $ref: '#/components/responses/200ExecutionDetails'

我在https://github.com/jvillane/aws-sam-step-functions-lambda 的 github 中提交了一个工作示例

Answer 2

创建您的 API Gateway 资源和方法。然后在“方法执行”设置中，在集成请求中，使用以下设置：

• 集成类型：AWS 服务
• AWS 区域：您的区域
• AWS 服务：Step Functions
• AWS 子域：你的子域，如果你有 - 我把它留空
• HTTP 方法：POST
• 操作：开始执行
• 执行角色：需要是具有 StepFunction 启动执行策略的角色，例如 arn:aws:iam::aws:policy/AWSStepFunctionsFullAccess
• 凭据缓存：我将其保留为默认值
• 内容处理：直通

然后是魔法。再往下，在 Body Mapping Templates 下：

• 请求正文直通：从不
• 添加映射模板：application/json

在模板文本框中进一步向下：

#set($input = $input.json('$'))
{
   "input": "$util.escapeJavaScript($input)",
   "stateMachineArn": "arn:aws:states:eu-west-1:123456789012:stateMachine:yourStepFunctionName"
}

这会将发布到 API Gateway 的 json 有效负载传递给 Step Function。

省略执行名称，以便每次调用 API Gateway 都会创建一个新的执行。