using Cloudformation ref with awscli in userData

问题

"aws ec2 create-tags --resources xxxxxx --tags Key=Team,Value=everybody --region { \"Ref\" : \"region\" } --out text\n"

The above line/command I am using in my Cloudformation userData, It is not getting executed , I am getting the following error when I debugged :

aws: error: argument --region: Invalid choice, valid choices are:

ap-southeast-1 | us-gov-west-1 
ap-northeast-1 | eu-west-1 
fips-us-gov-west-1 | us-west-1 
us-west-2 | us-east-1 
cn-north-1 | ap-southeast-2 
sa-east-1

My region name is taken as input parameter for Cloudformation script. Thats why I used ref in --region option.

Is this wrong ? Is it possible to use ref with awscli commands in Cloudformation ?

Thanks

回答1:

The UserData is a string in your Cloud Formation template, and therefore the {"Ref": "region"} is not expanded so the literal {"Ref": "region"} is being passed to the --region argument.

you could try

{"Fn::Join": [" ", ["aws ec2 create-tags --resources xxxxxx --tags Key=Team,Value=everybody --region", {"Ref": "region"}, "--out text\n"]]} 

The docs provide information on the Fn::Join function http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-join.html

Also this example template shows UserData including a Ref for the region parameter

https://s3.amazonaws.com/cloudformation-templates-us-east-1/vpc_single_instance_in_subnet.template

来源：https://stackoverflow.com/questions/39314105/using-cloudformation-ref-with-awscli-in-userdata