CloudFormation passing parameters from CodePipeline

Question

I have a SAM application and a CodePipeline setup to deploy it. I want to pass parameters down from my Pipeline into the SAM's YAML file. I tried using ParameterOverrides but seem to still get:

Parameters: [AppName] must have values (Service: AmazonCloudFormation; Status Code: 400; Error Code: ValidationError; Request ID: 46d1dfd6-9a9a-11e7-a59d-999618d6a174)

My sam.yml parameters definations

AWSTemplateFormatVersion : '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Parameters:
  AppName:
    Type: String
    Description: Prefix for resources

The part defining the parameters overrides:

    - Name: ExecuteChangeSet
      Actions:
      - Name: Lambda
        ActionTypeId:
          Category: Deploy
          Owner: AWS
          Version: 1
          Provider: CloudFormation
        Configuration:
          ActionMode: CHANGE_SET_EXECUTE
          ChangeSetName: !Sub
            - '${PipelineName}-lambda'
            - {PipelineName: !Ref PipelineName}
          StackName: !Sub
            - '${PipelineName}-lambda'
            - {PipelineName: !Ref PipelineName}
          ParameterOverrides: !Sub '{"AppName": "${PipelineName}-lambda"}'

Whats is wrong with this?

Answer 1

It appears that you're attempting to apply the ParameterOverrides during a CHANGE_SET_EXECUTE action mode. If I'm not mistaken, under the hood, this maps down to CloudFormations ExecuteChangeSet action, which does not have a Parameters property.

The solution to this is to apply the Parameters when you create the change set. This will be done in CodePipeline with a CHANGE_SET_REPLACE action mode. Alternatively, you could look into the CREATE_UPDATE. Check out AWS CloudFormation Configuration Properties for more details.

Here's a sample that creates, then executes the change set

- Name: CreateChangeSet
  Actions:
    - Name: Lambda
      ActionTypeId:
        Category: Deploy
        Owner: AWS
        Version: 1
        Provider: CloudFormation
      InputArtifacts:
        - Name: BuildOutputArtifact
      Configuration:
        ActionMode: CHANGE_SET_REPLACE
        ChangeSetName: !Sub
          - '${PipelineName}-lambda'
          - {PipelineName: !Ref PipelineName}
        StackName: !Sub
          - '${PipelineName}-lambda'
          - {PipelineName: !Ref PipelineName}
        ParameterOverrides: !Ref ProjectParameterOverrides
        TemplatePath: BuildOutputArtifact::SamDeploymentTemplate.yaml
- Name: ExecuteChangeSet
  Actions:
  - Name: Lambda
    ActionTypeId:
      Category: Deploy
      Owner: AWS
      Version: 1
      Provider: CloudFormation
    Configuration:
      ActionMode: CHANGE_SET_EXECUTE
      ChangeSetName: !Sub
        - '${PipelineName}-lambda'
        - {PipelineName: !Ref PipelineName}
      StackName: !Sub
        - '${PipelineName}-lambda'
        - {PipelineName: !Ref PipelineName}