In a GitHub Actions workflow definition file, there's a set of built-in functions that you can use in expressions.
For example: ${{ toJson(github) }}
Are there any string manipulation functions that can be used in an expression, such as toLowerCase?
The documentation page doesn't mention any. However, I'm wondering if Github uses some sort of standard templating / expression eval library under the hood which has provides a larger set of functions out of the box.
Impossible. GitHub expressions doesn't allow string modification, only concatenation.
You could do almost the same with a custom step in a build job, but this means that you won't be able to use that variable everywhere (for example "processed" environment name is out of the question).
env:
UPPERCASE_VAR: "HELLO"
steps:
- id: toLowerCase
run: INPUT=${{ env.UPPERCASE_VAR }} echo "::set-output name=lowerCaseValue::${INPUT,,}"
- run: echo ${{steps.toLowerCase.outputs.lowerCaseValue}}
::set-output is deprecated, see github.blog/changelog/…I usually start by setting all global variables that I will use throughout the workflow.
jobs:
variables:
outputs:
tag_name: ${{ steps.var.outputs.tag_name}}
runs-on: "ubuntu-latest"
steps:
- name: Setting global variables
uses: actions/github-script@v6
id: var
with:
script: |
core.setOutput('tag_name', '${{ github.head_ref }}'.toLowerCase().replaceAll(/[/.]/g, '-').trim('-'));
Usage:
deploy:
needs: [build, variables]
runs-on: [ self-hosted, preview ]
env:
TAG_NAME: ${{ needs.variables.outputs.tag_name }}
step:
-name: Echo variables
run: |
echo ${{ needs.variables.outputs.tag_name }}
echo ${{ env.TAG_NAME}}
After encountering some issues with the top voted answer, I found that it was not working (showing a blank string) because it only works inside the context. Here is the solution I found:
steps:
- id: toLowerCase
run: echo "::set-output name=lowerCaseValue::${UPPERCASE_VAR,,}"
env:
UPPERCASE_VAR: ${{ env.UPPERCASE_VAR }}
- run: echo ${{steps.toLowerCase.outputs.lowerCaseValue}}
Here, we're defining the UPPERCASE_VAR environment variable as an input variable of the toLowerCase step. Then, in the run command, we're using the ${UPPERCASE_VAR,,} syntax to convert the value of the variable to lowercase and assign it to the lowerCaseValue output variable. Finally, we're defining the UPPERCASE_VAR environment variable inside the step, so that it's available within the shell command.
A new variant converting a string to lowercase without deprecated set-output.
The new environment variable >>${GITHUB_OUTPUT} is in use.
env:
VAR_UPPERCASE: "HELLO"
jobs:
MyJob:
steps:
- name: Convert to lowercase
id: convert2lowercase
run: INPUT=$VAR_UPPERCASE; echo "VAR_LOWERCASE=${INPUT,,}">>${GITHUB_OUTPUT}
- run: echo ${{steps.convert2lowercase.outputs.VAR_LOWERCASE}}
I wanted to replace some chars in git version strings and was able to make a step like so:
- name: prepare version string
id: prep_version
run: |
export test_version=$(echo ${{ steps.tag_version.outputs.new_version }} | sed 's/[^0-9,a-z,A-Z]/\-/g')
echo ::set-output name=version::$test_version
that worked pretty good for me... so really we have anything that we could put on a cmd line
use the tr command in the runner OS
somejob:
name: a job with a step that needs lower case
runs-on: ubuntu-latest
steps:
- name: this is the job that needs lower case
env:
all_lower_case: $(echo ${{ inputs.upper_and_lower_case }} | tr '[:upper:]' '[:lower:]')
run: |
echo "this should be like toLower: ${{env.all_lower_case }}"
