Serverless CloudFormation template error instance of Fn::GetAtt references undefined resource - aws-cloudformation

Question

I'm trying to setup a new repo and I keep getting the error
The CloudFormation template is invalid: Template error: instance of Fn::GetAtt
references undefined resource uatLambdaRole
in my uat stage, however the dev stage with the exact same format works fine.
I have a resource file for each of these environments.
dev
devLambdaRole:
Type: AWS::IAM::Role
Properties:
RoleName: dev-lambda-role # The name of the role to be created in aws
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal:
Service:
- lambda.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/AWSLambdaFullAccess
#Documentation states the below policy is included automatically when you add VPC configuration but it is currently bugged.
- arn:aws:iam::aws:policy/service-role/AWSLambdaVPCAccessExecutionRole
uat
uatLambdaRole:
Type: AWS::IAM::Role
Properties:
RoleName: uat-lambda-role # The name of the role to be created in aws
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal:
Service:
- lambda.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/AWSLambdaFullAccess
#Documentation states the below policy is included automatically when you add VPC configuration but it is currently bugged.
- arn:aws:iam::aws:policy/service-role/AWSLambdaVPCAccessExecutionRole
In my serverless.yml my role is defined as
role: ${self:custom.stage}LambdaRole
and the stage is set as
custom:
stage: ${opt:stage, self:provider.stage}
Running serverless deploy --stage dev --verbose succeeds, but running serverless deploy --stage uat --verbose fails with the error. Can anyone see what I'm doing wrong? The uat resource was copied directly from the dev one with only the stage name change.
Here is a screenshot of the directory the resource files are in

Answer 1

I had the same issue, eventually I discovered that my SQS queue name wasn't the same in all 3 places. The following 3 places that the SQS name should match are shown below:
...
functions:
mylambda:
handler: sqsHandler.handler
events:
- sqs:
arn:
Fn::GetAtt:
- mySqsName # <= Make sure that these match
- Arn
resources:
Resources:
mySqsName: # <= Make sure that these match
Type: "AWS::SQS::Queue"
Properties:
QueueName: "mySqsName" # <= Make sure that these match
FifoQueue: true

Answer 2

Ended up here with the same error message. My issue ended up being that I got the "resource" and "Resource" keys in serverless.yml backwards.
Correct:
resources: # <-- lowercase "r" first
Resources: # <-- uppercase "R" second
LambdaRole:
Type: AWS::IAM::Role
Properties:
...
🤦‍♂️

Answer 3

I missed copying a key part of my config here, the actual reference to my Resources file
resources:
Resources: ${file(./serverless-resources/${self:provider.stage}-resources.yml)}
The issue was that I had copied this from a guide and had accientally used self:provider.stage rather than self:custom.stage. When I changed this, it could then deploy.

Answer 4

Indentation Issue
In general, when YAML isn't working I start by checking the indentation.
I hit this issue in my case one of my resources was indented too much, therefore, putting the resource in the wrong node/object. The resources should be two indents in as they're in node resources sub-node Resources
For more info on this see yaml docs