Add 'lowercase' and other string manipulation functions

[chriskuech]

Please add more GitHub Actions expression functions for manipulating strings. Specifically, a lowercase function would be very beneficial, but generally, there is no way to set environment variables across the entire workflow if they require even basic manipulation (such as converting to lowercase).

Motivation: https://github.community/t/github-actions-repository-name-must-be-lowercase/184924

[ethomson]

That's true; I don't want to add too many functions to the syntax, but there are a few that would be very useful, including case changing. I appreciate your feedback, and we'll put it on the backlog.

[lukasz-mitka]

There are workarounds if anyone is interested:
https://github.com/ASzc/change-string-case-action
https://github.community/t/additional-function-s-lowercase-uppercase/140632/2

That said, I would love to have this built in.

[Entepotenz]

I wrote an alternative to the ASzc/change-string-case-action version.
https://github.com/Entepotenz/change-string-case-action-min-dependencies

It is using pure python for the string conversion.
It does not depend on any library and therefore does not require any maintenance from security perspective :-)
Additionally I have a couple of tests running automatically before publishing.

[mpusz]

Another motivational example: conan-io/conan#11705.

[dahlia]

It's not that problematic when you need to change letter cases in shell, because shells usually has built-in feature for that (and I believe it shows how frequent we need changing letter cases). However, when you need to change letter cases before put it in input parameters of actions, it gets us in trouble.

Here's another motivational example. Whereas GitHub's container registry disallows image names to contain any upper letters, github.repository preserve letter cases (i.e., if you put any upper letters in your org name or repo name github.repository contains upper letters too). Therefore, I cannot reuse github.repository for image names:

- uses: docker/build-push-action@v3
  with:
    push: true
    tags: ghcr.io/${{ github.repository }}:latest  # Does not work if any upper letter appears

At present, I need to work around this problem by utilizing shell script:

- id: lower-repo
  shell: pwsh
  run: |
    "::set-output name=repository::$($env:GITHUB_REPOSITORY.ToLowerInvariant())"
- uses: docker/build-push-action@v3
  with:
    push: true
    tags: ghcr.io/${{ steps.lower-repo.outputs.repository }}:latest

[Silvenga]

It should be noted that cache syntax can't make use of docker-meta, so lowercasing the repository name is still required.

[spectrapulse]

It should be noted that cache syntax can't make use of docker-meta, so lowercasing the repository name is still required.

I'm running into a case of this as we speak. So it kind of sucks that there's still no proper solution for this.

[lukasz-mitka]

It's ridiculous how Github ignores these obviously missing features. To little AI in it for them to bother.

[yanyongyu]

I encountered the same problem when using docker buildx. My work around is using the bash lower transformation:

- id: lower-repo
  run: |
    echo "IMAGE=${GITHUB_REPOSITORY@L}" >> $GITHUB_OUTPUT

[tinohager]

These two variants are suitable for me

Bash string to lowercase

    - id: lower-repo
      name: Repository to lowercase
      run: |
        echo "repository=${GITHUB_REPOSITORY@L}" >> $GITHUB_OUTPUT
    - name: Build and push
      uses: docker/build-push-action@v5
      with:
        context: .
        file: ./src/Dockerfile
        push: true
        tags: ghcr.io/${{ steps.lower-repo.outputs.repository }}:latest

with powershell - ToLowerInvariant()

    - id: lower-repo
      name: Repository to lowercase
      shell: pwsh
      run: |
        "::set-output name=repository::$($env:GITHUB_REPOSITORY.ToLowerInvariant())"
    - name: Build and push
      uses: docker/build-push-action@v5
      with:
        context: .
        file: ./src/Dockerfile
        push: true
        tags: ghcr.io/${{ steps.lower-repo.outputs.repository }}:latest

[jgwinner]

Another thing I ran into lately, which could probably be argued against:

I had job with an `if: inputs.stuff=='string' and of course, users may type mixed case and spoil the if check.

Still, a simple lower() would help in a lot of areas. I agree if you need more parameter handling than the typical case conversions, then dropping into a shell would be better, but we had a couple of jobs that run on different servers, and it's handy to reliably build if checks into jobs and steps that aren't foiled by arbitrary strings (yes, I use 'option' when possible, that input is great!)

[KyleSanderson]

Good lord. Ran into the same thing trying to use the native github actions repository variables. There's just no decent way without having this as part of the language.

[vRune4]

In my case my predecessor settled on mixed case organization name (github.com/MyOrganization rather than github.com/myorganization). The organization name is just too useful not to use for e.g. docker image repository names, but certain operations failed (or looked odd) when not using lower case.

So now each workflow gets additional lines of code because there is no lower() function.

[marcoslopes]

Why not follow jq, jinja, tera where you can just pipe to a function.

${{ github.event.inputs.something | lower}}

https://keats.github.io/tera/docs/#built-ins

[tuxillo]

I thought the filter notation would work just like in jinja, apprently not. It would be a good addition instead of having to have intermediate steps to do dirty shell tricks.

[shayki5]

+1
Please make all the available functions in Azure Pipelines also in GitHub Actions:
https://learn.microsoft.com/en-us/azure/devops/pipelines/process/expressions?view=azure-devops#functions

[AndreKR]

Do I see that correctly that currently every single job that wants to use a Docker image named after the project has to include an extra step that makes a lowercase version of github.repository? No way to do this only once?

[lkfortuna]

Hey there from Actions 👋 - we do not have this currently on the roadmap, but I will look into what it takes to get this added. Just to set expectations at current funding i wouldn't expect this one to come for the next 6 months.

[shayki5]

Thank you.
Please check also https://github.com/orgs/community/discussions/25768.
This is a super useful feature!

[Dherlou]

Since six months have passed, any update/progress on this? :)

[polarathene]

How much funding/time does it cost to add support for basic case conversion? 🤔

It should be simple/straight-forward, at least for the common case of ASCII lowercase requested here.

If you are concerned about implementing support with more complexity, lower the scope to what's actually in demand for the time being and expand from there. Rust has a few methods for adjusting case on strings for example, one of those is make_ascii_lowercase().

Such functionality should not cost much time to implement. If the Actions team is unable to budget that, there is something seriously wrong.

[marcwittke]

mandatory reply: https://ericlippert.com/2003/10/28/how-many-microsoft-employees-does-it-take-to-change-a-lightbulb/

[saxonww]

Another idea is to avoid putting complex logic (which unfortunately includes case manipulation here) into the workflow definition. Write a script in whatever language is appropriate for the project, and do your manipulation there. Then call that script from your Actions workflow or composite action.

There are reasons why this might be a better idea. With scripts, you can run more of your workflow locally, without needing whatever passes as a 'run your Actions locally' tool to do it. This can cut down on the amount of Actions minutes you consume testing stuff. It also makes it easier to adapt to Actions syntax changes and/or move to another CI tool, should you need to do that. Finally, a local script in the language you're already using is probably more familiar to your team than Actions yaml.