AWS Step Functions传递初始参数至Fargate容器问题求助

用Fargate容器搭建了一个简单工作流，容器仅返回输入内容。工作流输入为：

{
  "value": "FALSE"
}

• Choice状态运行符合预期：$.value被识别为FALSE，并触发ECS RunTask-FALSE容器。
• 该容器本应接收并返回字符串"FALSE"，但实际返回字符串"$.value"，输入值未被解析。ECS控制台任务运行情况：
  

请问如何将初始参数传递给该任务？附状态机定义如下：

{
    "Comment": "A description of my state machine",
    "StartAt": "Choice",
    "States": {
        "Choice": {
            "Type": "Choice",
            "Choices": [
                {
                    "Variable": "$.value",
                    "StringEquals": "FALSE",
                    "Next": "ECS RunTask-FALSE"
                }
            ],
            "Default": "ECS RunTask-TRUE"
        },
        "ECS RunTask-FALSE": {
            "Type": "Task",
            "Resource": "arn:aws:states:::ecs:runTask.sync",
            "Parameters": {
                "LaunchType": "FARGATE",
                "Cluster": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:cluster/portal",
                "TaskDefinition": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:task-definition/simple:4",
                "Overrides": {
                    "ContainerOverrides": [
                        {
                            "Name": "simple",
                            "Command": ["$.value"]
                        }
                    ]
                },
                "NetworkConfiguration": {
                    "AwsvpcConfiguration": {
                        "Subnets": [
                            "subnet-001f85595e8af43cf",
                            "subnet-05e742358ac59ae04"
                        ],
                        "SecurityGroups": [
                            "sg-0948e5328861ae667"
                        ],
                        "AssignPublicIp": "ENABLED"
                    }
                }
            },
            "End": true
        },
        "ECS RunTask-TRUE": {
            "Type": "Task",
            "Resource": "arn:aws:states:::ecs:runTask.sync",
            "Parameters": {
                "LaunchType": "FARGATE",
                "Cluster": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:cluster/portal",
                "TaskDefinition": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:task-definition/simple:4",
                "NetworkConfiguration": {
                    "AwsvpcConfiguration": {
                        "Subnets": [
                            "subnet-001f85595e8af43cf",
                            "subnet-05e742358ac59ae04"
                        ],
                        "SecurityGroups": [
                            "sg-0948e5328861ae667"
                        ],
                        "AssignPublicIp": "ENABLED"
                    }
                }
            },
            "End": true
        }
    }
}

问题核心是：ECS RunTask-FALSE状态的ContainerOverrides.Command中直接写了["$.value"]，Step Functions会将其作为字符串字面量传递给容器，而非解析输入中的value字段。以下两种方法可解决：

方法1：使用Fn::Sub替换变量 #

修改ECS RunTask-FALSE中的Command部分，通过Fn::Sub引用输入的value字段，自动替换为实际值：

"Overrides": {
  "ContainerOverrides": [
    {
      "Name": "simple",
      "Command": [
        {
          "Fn::Sub": "${value}"
        }
      ]
    }
  ]
}

方法2：直接使用JSON Path引用 #

若Step Functions参数解析生效，也可直接使用完整JSON Path格式，明确指定输入变量：

"Overrides": {
  "ContainerOverrides": [
    {
      "Name": "simple",
      "Command": [
        "$.value"
      ]
    }
  ]
}

若此方法不生效，优先使用方法1。

修改后的完整ECS RunTask-FALSE状态 #

"ECS RunTask-FALSE": {
  "Type": "Task",
  "Resource": "arn:aws:states:::ecs:runTask.sync",
  "Parameters": {
    "LaunchType": "FARGATE",
    "Cluster": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:cluster/portal",
    "TaskDefinition": "arn:aws:ecs:us-east-2:xxxxxxxxxxx:task-definition/simple:4",
    "Overrides": {
      "ContainerOverrides": [
        {
          "Name": "simple",
          "Command": [
            {
              "Fn::Sub": "${value}"
            }
          ]
        }
      ]
    },
    "NetworkConfiguration": {
      "AwsvpcConfiguration": {
        "Subnets": [
          "subnet-001f85595e8af43cf",
          "subnet-05e742358ac59ae04"
        ],
        "SecurityGroups": [
          "sg-0948e5328861ae667"
        ],
        "AssignPublicIp": "ENABLED"
      }
    }
  },
  "End": true
}

内容的提问来源于stack exchange，提问作者jlo-gmail