Cloudformation Unable to Use Outputted Parameters with Nested Stacks - amazon-web-services

Question

I'm trying my hand at Cloudformation nested stacks. The idea is that I create a VPC, S3 bucket, Codebuild project, and Codepipeline pipeline using Cloudformation.
My Problem: Cloudformation is saying that the following parameters (outputted by child stacks) require values:
Vpc
PrivateSubnet1
PrivateSubnet2
PrivateSubnet3
BucketName
These params should have values as the value exists when I look at a completed child stack in the console.
I'll just show the templates for the parent, s3, and codepipeline. With regards to these three templates the problem is that I am unable to use an output BucketName from S3Stack in my CodePipelineStack
My Code:
cfn-main.yaml
AWSTemplateFormatVersion: 2010-09-09
Description: root template for codepipeline poc
Parameters:
BucketName:
Type: String
VpcName:
Description: name of the vpc
Type: String
Default: sandbox
DockerUsername:
Type: String
Description: username for hub.docker
Default: seanturner026
DockerPassword:
Type: String
Description: password for hub.docker
Default: /codebuild/docker/password
Environment:
Type: String
Description: environment
AllowedValues:
- dev
- prod
Default: dev
Vpc:
Type: AWS::EC2::VPC::Id
PrivateSubnet1:
Type: AWS::EC2::Subnet::Id
PrivateSubnet2:
Type: AWS::EC2::Subnet::Id
PrivateSubnet3:
Type: AWS::EC2::Subnet::Id
GithubRepository:
Type: String
Description: github repository
Default: aws-codepipeline-poc
GithubBranch:
Type: String
Description: github branch
Default: master
GithubOwner:
Type: String
Description: github owner
Default: SeanTurner026
GithubToken:
Type: String
Description: github token for codepipeline
NoEcho: true
Resources:
VpcStack:
Type: AWS::CloudFormation::Stack
Properties:
Parameters:
VpcName: !Ref VpcName
TemplateURL: resources/vpc.yaml
S3Stack:
Type: AWS::CloudFormation::Stack
Properties:
TemplateURL: resources/s3.yaml
CodeBuildStack:
Type: AWS::CloudFormation::Stack
Properties:
Parameters:
Environment: !Ref Environment
DockerUsername: !Ref DockerUsername
DockerPassword: !Ref DockerPassword
Vpc: !GetAtt VpcStack.Outputs.VpcId
PrivateSubnet1: !GetAtt VpcStack.Outputs.PrivateSubnetId1
PrivateSubnet2: !GetAtt VpcStack.Outputs.PrivateSubnetId2
PrivateSubnet3: !GetAtt VpcStack.Outputs.PrivateSubnetId3
TemplateURL: resources/codebuild.yaml
CodePipelineStack:
Type: AWS::CloudFormation::Stack
Properties:
Parameters:
Environment: !Ref Environment
GithubRepository: !Ref GithubRepository
GithubBranch: !Ref GithubBranch
GithubOwner: !Ref GithubOwner
GithubToken: !Ref GithubToken
S3: !GetAtt S3Stack.Outputs.BucketName
TemplateURL: resources/codepipeline.yaml
s3.yaml
AWSTemplateFormatVersion: 2010-09-09
Description: s3 bucket for aws codepipeline poc
Resources:
S3:
Type: "AWS::S3::Bucket"
Properties:
BucketName: "aws-sean-codepipeline-poc"
Outputs:
BucketName:
Description: S3 bucket name
Value: !Ref S3
codepipeline.yaml -- Please see ArtifactStore. This is where cloudformation is seeing my parameter BucketName as value-less.
AWSTemplateFormatVersion: 2010-09-09
Description: codepipeline for aws codepipeline poc
Parameters:
BucketName:
Type: String
Environment:
Type: String
Description: environment
AllowedValues:
- dev
- prod
Default: dev
GithubRepository:
Type: String
Description: github repository
Default: aws-codepipeline-poc
GithubBranch:
Type: String
Description: github branch
Default: master
GithubOwner:
Type: String
Description: github owner
Default: SeanTurner026
GithubToken:
Type: String
Description: github token for codepipeline
NoEcho: true
Resources:
CodePipelineRole:
Type: "AWS::IAM::Role"
Properties:
RoleName: !Join
- ""
- - !Ref AWS::StackName
- "-code-pipeline-role-"
- !Ref Environment
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
Effect: "Allow"
Principal:
Service: "codepipeline.amazonaws.com"
Action: "sts:AssumeRole"
CodePipelinePolicy:
Type: "AWS::IAM::Policy"
Properties:
PolicyName: !Join
- ""
- - !Ref AWS::StackName
- "-code-pipeline-policy-"
- !Ref Environment
PolicyDocument:
Version: "2012-10-17"
Statement:
Effect: Allow
Action:
- logs:CreateLogGroup
- logs:CreateLogStream
- logs:PutLogEvents
- s3:putObject
- s3:getObject
- codebuild:*
Resource:
- "*"
Roles:
- !Ref CodePipelineRole
Pipeline:
Type: "AWS::CodePipeline::Pipeline"
Properties:
Name: !Join
- ""
- - "code-pipeline-poc-"
- !Ref AWS::StackName
ArtifactStore:
Location: !Ref BucketName
Type: S3
RestartExecutionOnUpdate: true
RoleArn: !Join
- ""
- - "arn:aws:iam::"
- !Ref AWS::AccountId
- ":role/"
- !Ref CodePipelineRole
Stages:
- Name: checkout-source-code
Actions:
- Name: SourceAction
RunOrder: 1
ActionTypeId:
Category: Source
Owner: ThirdParty
Provider: GitHub
Version: 1
Configuration:
Owner: !Ref GithubOwner
Repo: !Ref GithubRepository
Branch: !Ref GithubBranch
PollForSourceChanges: true
OAuthToken: !Ref GithubToken
OutputArtifacts:
- Name: source-code
- Name: docker-build-push
Actions:
- Name: build-push-job
RunOrder: 1
InputArtifacts:
- Name: source-code
ActionTypeId:
Category: Build
Owner: AWS
Provider: CodeBuild
Version: 1
Configuration:
ProjectName: !Ref BuildPushJob
OutputArtifacts:
- Name: build-push-job
Sorry if this is too verbose. If missed above, the problem is that ArtifactStore in the codepipeline.yaml is seeing my parameter BucketName as value-less, despite the value being outputted by S3Stack.

Answer 1

You pass the parameter as S3 but the template is expecting it as BucketName.