Additional function(s): lowercase|uppercase

[DazWilkin]

Noob GitHub Actions user here.

My GitHub username includes uppercase characters.

My first GitHub Actions workflow builds a container image to push to GitHub Container Registry.

Container registries require lowercase repo names.

I wanted to be able to:

tags: ghcr.io/${{ github.repository }}:${{ github.sha }}

But this errors because github.repository_owner includes uppercase.

I was unable to find a function nor any other way to pipe this value into lowercase and think such a function (and perhaps its companion uppercase) would be useful.

tags: ghcr.io/${{ lowercase(github.repository) }}:${{ github.sha }}

Or, is there a better way to achieve this?

env:
  REPO: my-username/some-repo
...
steps:
   ...
   tags: ghcr.io/${{ env.REPO }}:${{ github.sha }}

[airtower-luna]

The env approach is what I’d do, except that I’d use Bash parameter expansion to convert the case instead of hardcoding it:

      - name: downcase REPO
        run: |
          echo "REPO=${GITHUB_REPOSITORY,,}" >>${GITHUB_ENV}

Or if you need the tag in a run step you could do the parameter expansion right there.

[bergus]

Imo it's slightly nicer to use the (new-ish) operator syntax of bash:

echo "REPO=${GITHUB_REPOSITORY@L}" >> "${GITHUB_ENV}"

U
The expansion is a string that is the value of parameter with lowercase alphabetic characters converted to uppercase.

u
The expansion is a string that is the value of parameter with the first character converted to uppercase, if it is alphabetic.

L
The expansion is a string that is the value of parameter with uppercase alphabetic characters converted to lowercase.

[Likqez]

When you write a variable definition to GITHUB_ENV, subsequent steps will have it as an environment variable. For example

See here.

[rzaitov]

I found the lack of simple string manipulation functions very inconvenient. If someone wants to use the upper/lower case parameter expansion feature of Bash, ensure that your target runner has Bash v4.0 or above. Upper case parameter expansion has been available in Bash since version 4 bash-faq-061. Unfortunately, macOS runners have Bash 3.2, so this workaround is not available on such systems. One possible solution that works on both Ubuntu and macOS runners is to use tr (see comments below).

[alan-czajkowski]

I refuse to accept this as an answer out of principle.

[Simran-B]

While using built-in shell functionality is probably more succinct, you could also use a string manipulation action if you want something that works the same regardless of the shell type:

    steps:
      - id: string
        uses: ASzc/change-string-case-action@v1
        with:
          string: ${{ github.repository }}
      - run: |
          echo "${{ steps.string.outputs.lowercase }}"

[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.

[hu1buerger]

@Entepotenz sounds reasonable to me

[ArnoudAtBreenservices]

How would you use it inside the run step, then?

[airtower-luna]

When you write a variable definition to GITHUB_ENV, subsequent steps will have it as an environment variable. For example:

      - name: downcase REPO
        run: |
          echo "REPO=${GITHUB_REPOSITORY,,}" >>${GITHUB_ENV}
      - name: use REPO
        run: echo "The value of REPO is: ${REPO}"

[FrostyLeaf]

The following commands can do this trick:

ABC=$(echo 'console.log("abc".toUpperCase())' | node -);
echo $ABC

In you case, it could be:

repo=$(echo 'console.log("${{ github.repository }}".toLowerCase())' | node -)
tags: ghcr.io/${repo}:${{ github.sha }}

[ystxn]

the reply before you already provided the most succinct solution. your response is confusing in suggesting that it's possible to run script within a step and interpret the value within a field in the same step, which is not possible.

[gerardnico]

This is the solution for a multi runner workflow.

• Bash substitution do not work with macos that is still on bash version 3.2.57(1)-release
• And you don't need to know the python version to use the correct print syntax

      - name: Properties
        id: props
        shell: bash
        run: |
          # Runner real id 
          RUNNER_ID=$(echo 'console.log("${{ runner.os }}-${{ runner.arch }}".toLowerCase())' | node -);
          echo "runner_id=${RUNNER_ID}" >> $GITHUB_OUTPUT
     - name: Usage
       run: echo "The runner id is: ${{ steps.props.outputs.runner_id }}"

Thanks !

[FrostyLeaf]

Python also does the exactly same thing:

ABC=$(echo 'print("abc".upper())' | python3.9 -)
echo $ABC

[Entepotenz]

IMHO:
I would feel uncomfortable running those bash commands basically calling eval in python or nodejs.

I am talking about those examples:

ABC=$(echo 'print("abc".upper())' | python3.9 -)
echo $ABC

ABC=$(echo 'console.log("abc".toUpperCase())' | node -);
echo $ABC

I think those two links describe much more secure solutions:

• https://github.com/orgs/community/discussions/25768#discussioncomment-4557471
• https://github.com/orgs/community/discussions/25768#discussioncomment-3249184

You can also check out the security best practices for GitHub actions: https://res.cloudinary.com/da8kiytlc/image/upload/v1651737641/GitHub-Actions-Security-Best-Practices_cheatsheet.pdf

[d3vpasha]

I don't like any answer above, for me, Github actions must have some built-in functions to do usual things like uppercase, camelcase, lowercase, etc..

[shellscape]

See this answer https://stackoverflow.com/a/63315136/416845 on how to use ${var^^} to uppercase

[ALERTua]

These worked for me:

      - name: lowercase github.repository
        run: |
          echo "IMAGE_NAME=`echo ${{github.repository}} | tr '[:upper:]' '[:lower:]'`" >>${GITHUB_ENV}

      - name: lowercase github.repository
        run: |
          echo "IMAGE_NAME=${GITHUB_REPOSITORY@L}" >> ${GITHUB_ENV}

then ${{ env.IMAGE_NAME }} or "${{ env.IMAGE_NAME }}:latest"

[gerardnico]

You need tr that is not on Windows...

[bergus]

See also https://github.com/orgs/community/discussions/10553

[lordfolken]

None of these answers solve the actual problem.
If you want to run steps inside an image, then you need to first to be able to specify the image path, in order to pull the image.
Without variable expansion, an additional job is necessary that first lowercases the variable and then using that in a subsequent container job.
What a waste of resources.

[esaporski]

GitHub Actions has a lot of potential, but right now it feels like a half-finished product.

[alan-czajkowski]

GitHub Actions is quite possibly the worst pipeline orchestration tool I've ever used

[Solenhya]

Not being able to handle people using uppercase letter NAMING thing is madness. Imo if they can't handle uppercase they should include a parser

[randomairborne]

If i were to want to set a top-level environment variable, I have to be able to process that with the template system. There is no other option. Right now, it seems like this is impossible.

[alexander-williamson]

Today we wanted to use something like this:

${{ inputs.SOMETHING.lowercase }}

But I don't know if that's possible? Something for us to investigate.

[Firefishy]

docker/metadata-action automatically normalises image names, including fixing the casing.

To explicitly use it to extract the lower case name into ${env.IMAGE_NAME}:

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ inputs.SOMETHING }}

      - name: Set normalised image name
        run: |
          repo_image=$(jq -r '.tags[0]' <<< "$DOCKER_METADATA_OUTPUT_JSON" | cut -d: -f1)
          echo "IMAGE_NAME =$repo_image" >>${GITHUB_ENV}

Or likely more appropriately just use the steps.meta.outputs.tags:

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ inputs.SOMETHING }}
          
      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          tags: ${{ steps.meta.outputs.tags }}

[alan-czajkowski]

this is one of the saddest threads I've read regarding GitHub Actions ...

[ssbarnea]

This is what happens when product management focuses 100% on anything that has "AI" in its name, the other stuff gets deprioritized forever. When "UX" is no longer a priority, following the hype is.

[gerardnico]

The fact that they don't have any upper/lowercase and they impose on us runner

• os name such as macOs, Windows, Linux
• or arch such as X86, X64, ARM, or ARM64 is pretty astonishing.

I'm fighting for that. The first solution with bash substitution does not even work on macos that uses bash 3.2.57(1)-release.

I need to learn python to have a multiple os run ? pfff what a joke

[alan-czajkowski]

this entire thread is a sad joke

[gerardnico]

Azure pipeline does have it ...lower

[FuncProgLinux]

People adding AI to GitHub (fancy term to say UI over OpenAI/ChatGPT Tokens) would be seriously astonished if they learned how to code real things. But whatever green gremlins microshit has working over on GitHub clearly lack the skills to implement basic string manipulation in their pipelines for the container registry

Maybe their Copilot garbage knows the answer? Oh wait...

[excalq]

I just had Copilot in a code review suggest a hallucination: toLower(inputs.whatever). Disappointed.

[danielbayley]

*Error. Let’s call it what it is.

[BerGod]

i stumbled across this thread because of copilot.... time to turn it off

[alan-czajkowski]

I originally came here for answers, but now I occasionally visit this thread for the lolz, because God forbid this easy problem ever gets fixed ...