Concourse CI, git tag with constant value - concourse

Question

I would like to tag my git commits as they are deployed to the various environments in my concourse pipeline with the name of the environment. For example, in my UAT deployment job, I would like to do something like:
- put: master-resource <-- a git resource
params:
repository: master <-- the resource local directory
tag: 'uat'
force: true <-- replace the tag, if it already exists
tag_only: true
This would seem like a common -or at least simple, thing to do however the value of the 'tag' parameter can only be the path to a file -there is no option to pass a constant/literal value.
I see two possible solutions but none of them seems 'simple' enough:
Create a file myself, but to do that (ideally?) I wish there were some kind of file resource that I could use to create the file.
The last alternative would be to create a custom task, and even there I was struggling to find a way to pass the name of the tag as a parameter.
Any suggestions on what would be the best way to accomplish my goal in the simplest way, or alternatively how to implement options 1 or 2?
Thanks!

Answer 1

The reason that tag takes in a file is so that you can dynamically set the tag of the commit based on information you imply during the course of the pipeline.
So, the best way I can see to do something like this would be workflow #2 that you described above.
So you would want something like this:
- task: generate-git-tag
params:
TAG: {{some-passed-in-tag}}
config:
platform: linux
image_resource:
type: docker-image
source:
repository: ruby
outputs:
- name: tag-file
params:
TAG:
run:
path: /bin/bash
args:
- -c
- |
echo "${TAG}" >> tag-file/tag.txt
- put: master-resource <-- a git resource
params:
repository: master <-- the resource local directory
tag: tag-file/tag.txt
force: true <-- replace the tag, if it already exists
tag_only: true