AWS SAM: An error occurred (ValidationError) when calling the CreateChangeSet operation: Parameters: [IdentityNameParameter] must have values

Question

I want to get started with AWS SAM and I encounter this issue when trying to deploy to the AWS.

I am trying to deploy a 'Hello World!'-application that can be found here.

This is the error I encounter:

$ sam package --s3-bucket dolphin-code --s3-prefix prod --output-template-file packaged.yaml --region eu-central-1

Uploading to prod/de65208b144ad296cfdc39666a47ad1c  34671 / 34671.0  (100.00%)
Successfully packaged artifacts and wrote output template to file packaged.yaml.
Execute the following command to deploy the packaged template
sam deploy --template-file /builds/gitlab/dophin/apis/hello-world/packaged.yaml --stack-name 

$ sam deploy --template-file ./packaged.yaml --stack-name prod --capabilities CAPABILITY_IAM --region eu-central-1

Deploying with following values
===============================
Stack name                 : prod
Region                     : eu-central-1
Confirm changeset          : False
Deployment s3 bucket       : None
Capabilities               : ["CAPABILITY_IAM"]
Parameter overrides        : {}

Initiating deployment
=====================
Error: Failed to create changeset for the stack: prod, An error occurred (ValidationError) when 
calling the CreateChangeSet operation: Parameters: [IdentityNameParameter] must have values
ERROR: Job failed: exit code 1

For me, that seems to be an error in the AWS CLI and not in SAM directly, right?

Can anyone help me? Thanks in advance!

Solution

It seems that you are using a parameter in your sam template called "IdentityNameParameter", and it doesn't have a default value, thus Sam expects you to provide a value for it.

Either you set the value when you call your sam deploy using the flag --parameters-overrides

$ sam deploy --template-file ./packaged.yaml --stack-name prod --capabilities CAPABILITY_IAM --region eu-central-1 --parameter-overrides IdentityNameParameter=xyz

or give it a default value in your SAM template

Parameters: 
    IdentityNameParameter: 
      Type: String
      Default:"xyz"

You can read more about the sam deploy command here https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-cli-command-reference-sam-deploy.html