CODEWITHSUNDEEP
amazon-web-servicesaws-lambdaaws-cloudformationaws-sam-cliaws-sam
newbreedofgeek
newbreedofgeek

Reputation: 3616

Dynamic AWS Sam Schedule Event Input param

We are automating a lambda via SAM to run on a Schedule Event. We use YAML but we are unable to work out how to use !Sub to make the Input be dynamic.

If you read the sam documentation it says that Input needs to be a JSON formatted string

The following code works for us:

Events:
    Event1:
      Type: Schedule
      Properties:
        Schedule: rate(1 minute)
        Input: >-
          {
            "sqsUrl": "https://sqs.12344.url",
            "snsArn": "arn:val"
          }

But we need to insert dynamic params into the Input like so:

Events:
    Event1:
      Type: Schedule
      Properties:
        Schedule: rate(1 minute)
        Input: >-
          {
            "sqsUrl": "https://sqs.${AWS::AccountId}.url",
            "snsArn": "arn:val"
          }

We have tried to do this in multiple ways, using a !Sub but the deployment always fails saying that it needs to be valid JSON.

What is the correct way to make this JSON string use variables?

Thanks, Mark

Upvotes: 4

Views: 1921

Answers (2)

Jamie-505
Jamie-505

Reputation: 1260

I've used something like:

!Sub |
    {
      "sqsUrl": "https://sqs.${AWS::AccountId}.url",
      "snsArn": "arn:val"
    }

the | (and >- among others) define the way yaml handles the line breaks in the string.

Upvotes: 0

Oleksii Balenko
Oleksii Balenko

Reputation: 862

So, you should wrap all Input value (in your case this is json-string and of course it should be wrapped with some quotes) with the !Sub function.

Then, it will look like:

Input:
  Fn::Sub: '{"sqsUrl": "https://sqs.${AWS::AccountId}.url","snsArn": "arn:val"}'

Upvotes: 2

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