Getting "Template validation error: Invalid template resource property 'VPCID' " - amazon-web-services

Question

I am trying to create a VPC using AWS CloudFormation.
I built a VPC on its own, then I updated the existing stack by adding more components to the JSON template (components like subnets, internet gateways, NATs, route tables, etc.) - one component at a time.
My VPC created successfully but when I tried to update the stack with an internet gateway and attach to the VPC, I started getting the error Template validation error: Invalid template resource property 'VPCID'.
My JSON template is as follows:
{
"Parameters": {
"CIDRRange": {
"Description": "VPCCIDR Range (will be a /16 block)",
"Type": "String",
"Default": "10.251.0.0",
"AllowedValues": ["10.250.0.0","10.251.0.0"]
}
},
"Resources": {
"VPCBase": {
"Type": "AWS::EC2::VPC",
"Properties": {
"CidrBlock": { "Fn::Join" : ["", [{ "Ref" : "CIDRRange" }, "/16"]] },
"EnableDnsSupport": "True",
"EnableDnsHostnames": "True",
"Tags": [{ "Key": "Name", "Value": { "Fn::Join" : ["", [{ "Ref" : "AWS::StackName" }, "-VPC"]] } }]
}
},
"IGWBase" : {
"Type" : "AWS::EC2::InternetGateway",
"Properties" : {
"Tags" : [{ "Key": "Name", "Value": { "Fn::Join" : ["", [{ "Ref" : "AWS::StackName" }, "-IGW"]] } }]
}
},
"VGAIGWBase" : {
"Type" : "AWS::EC2::VPCGatewayAttachment",
"Properties" : {
"InternetGatewayId" : { "Ref" : "IGWBase" },
"VpcId" : { "Ref" : "VPCBase" }}
},
"Outputs": {
"VPCID" : { "Value" : { "Ref" : "VPCBase" } },
"DefaultSG" : { "Value" : { "Fn::GetAtt" : ["VPCBase", "DefaultSecurityGroup"] }}
}
}
}

Answer 1

Your formatting is a bit of a mess - I'd recommend going with yaml over json - but the problem is you're not closing the Resources: section.
You can validate a template with the cli with
aws cloudformation validate-template --template-body file://path.json
"VGAIGWBase" : {
"Type" : "AWS::EC2::VPCGatewayAttachment",
"Properties" : {
"InternetGatewayId" : { "Ref" : "IGWBase" },
"VpcId" : { "Ref" : "VPCBase" }
}
}
}, << ADD THIS
"Outputs": {
"VPCID" : { "Value" : { "Ref" : "VPCBase" } },
"DefaultSG" : { "Value" : { "Fn::GetAtt" : ["VPCBase", "DefaultSecurityGroup"] }}
}
}