Bash - Gitlab CI not converting variable to a string - bash

Question

I am using GitLab to deploy a project and have some environmental variables setup in the GitLab console which I use in my GitLab deployment script below:
- export S3_BUCKET="$(eval \$S3_BUCKET_${CI_COMMIT_REF_NAME^^})"
- aws s3 rm s3://$S3_BUCKET --recursive
My environmental variables are declared like so:
Key: s3_bucket_development
Value: https://dev.my-bucket.com
Key: s3_bucket_production
Value: https://prod.my-bucket.com
The plan is that it grabs the bucket URL from the environmental variables depending on which branch is trying to deploy (CI_COMMIT_REF_NAME).
The problem is that the S3_BUCKET variable does not seem to get set properly and I get the following error:
> export S3_BUCKET=$(eval \$S3_BUCKET_${CI_COMMIT_REF_NAME^^})
> /scripts-30283952-2040310190/step_script: line 150: https://dev.my-bucket.com: No such file or directory
It looks like it picks up the environmental variable value fine but does not set it properly - any ideas why?

Answer 1

It seems like you are trying to get the value of the variables S3_BUCKET_DEVELOPMENT and S3_BUCKET_PRODUCTION based on the value of CI_COMMIT_REF_NAME, you can do this by using parameter indirection:
$ a=b
$ b=c
$echo "${!a}" # c
and in your case, you would need a temporary variable as well, something like this might work:
- s3_bucket_variable=S3_BUCKET_${CI_COMMIT_REF_NAME^^}
- s3_bucket=${!s3_bucket_variable}
- aws s3 rm "s3://$s3_bucket" --recursive

Answer 2

You are basically telling bash to execute command, named https://dev.my-bucket.com, which obviously doesn't exist.
Since you want to assign output of command when using VAR=$(command) you should probably use echo
export S3_BUCKET=$(eval echo \$S3_BUCKET_${CI_COMMIT_REF_NAME^^})
Simple test:
VAR=HELL; OUTPUT="$(eval echo "\$S${VAR^^}")"; echo $OUTPUT
/bin/bash
It dynamically creates SHELL variable, and then successfully prints it