CloudFormation YAML 状态机:INVALID_JSON_DESCRIPTION无法识别的令牌

Question

我有以下代码来部署使用 CloudFormation 的 Step Functions 状态机：

...
DefinitionString: 
!Sub
- |
{
"StartAt": "Save Artifact to S3",
"States": {
"Save Artifact to S3": {
"Type": "Task",
"Resource": ${lambdaArn},
"Next": "Format Notification"
},
"Format Notification": {
"Type": "Task",
"Resource": ${lambda2Arn},
"Next": "Publish to SNS"
},
"Publish to SNS": {
"Type": "Task",
"Resource": "arn:aws:states:::sns:publish",
"Parameters": {
"TopicArn": ${snsArn},
"Message.$": "$.message",
"Subject.$": "$.subject"
},
"End": true
}
}
}
- lambdaArn: !GetAtt SavetoS3Function.Arn
lambda2Arn: !GetAtt NotifyUserFunction.Arn
snsArn: !Ref NotifyUserTopic
...

使用 SAM 在 AWS 上部署时，我收到以下错误：

Invalid State Machine Definition: 'INVALID_JSON_DESCRIPTION: Unrecognized token 'arn': was expecting ('true', 'false' or 'null')  at [Source: (String)...

其他一切看起来都正确，那么这是怎么回事？所有 Arn 都在定义字符串中被正确引用，因此这可能不是问题所在。

Answer 1

这应该是一个json，所以lambdaArn，lambda2Arn和snsArn应该用引号引起来：

{
"StartAt": "Save Artifact to S3",
"States": {
"Save Artifact to S3": {
"Type": "Task",
"Resource": "${lambdaArn}",
"Next": "Format Notification"
},
"Format Notification": {
"Type": "Task",
"Resource": "${lambda2Arn}",
"Next": "Publish to SNS"
},
"Publish to SNS": {
"Type": "Task",
"Resource": "arn:aws:states:::sns:publish",
"Parameters": {
"TopicArn": "${snsArn}",
"Message.$": "$.message",
"Subject.$": "$.subject"
},
"End": true
}
}