Github Actions - Variables
Parsing variables
Parsing variables with object type
Workflow :
- run: |
echo "github.event: $"
echo "github.event toJson: $GITHUB_EVENT"
env:
GITHUB_EVENT: $
Output:
github.event: Object
github.event toJson: {
after: 9da8166fcc52c437871a2e903b3e200a35c09a1e,
base_ref: null,
before: 1448cfbf10fc149b7d200d0a0e15493f41cc8896,
...
echo "github.event toJson: ${{ toJSON(github.event) }}" will raise error, must parse the variable to environment variable $GITHUB_EVENT at first. So when using toJson method to parse object type variable, it is recommended to send the value to an environment variable first.
Parsing variables with boolean type
Check with if:
on:
workflow_dispatch:
inputs:
print_tags:
description: 'True to print to STDOUT'
required: true
type: boolean
jobs:
print-tag:
runs-on: ubuntu-latest
# all the 4 syntaxes below are valid
if: inputs.print_tags
if: ${{ inputs.print_tags }}
if: inputs.print_tags == true
if: ${{ inputs.print_tags == true}}
steps:
- name: Print the input tag to STDOUT
run: echo The tags are ${{ inputs.tags }}
- name: Print the input tag to STDOUT
# in bash, compare boolean with string value
run: |
if [[ "${{ inputs.print_tags }}" == "true" ]]; then
echo The tags are ${{ inputs.tags }}
else
echo "print_tags is false"
fi
if [[ "$PRINT_TAGS" == "true" ]]; then
echo The tags are ${{ inputs.tags }}
else
echo "print_tags is false"
fi
env:
PRINT_TAGS: ${{ inputs.print_tags }}
Never use if: ${{ inputs.print_tags }} == false with == outside of {{}}, it will always be true.
Passing variables
Passing data between steps inside a job
Passing by $GITHUB_ENV between steps
You can make an environment variable available to any subsequent steps in a workflow job by defining or updating the environment variable and writing this to the GITHUB_ENV environment file.
- run: echo "var_1=value1" >> $GITHUB_ENV
- run: echo "var_1: $var1"
Passing by $GITHUB_OUTPUT between steps
Sets a step’s output parameter. Note that the step will need an id to be defined to later retrieve the output value
Passing data between jobs inside a workflow
Passing by artifacts between jobs
You can use the upload-artifact and download-artifact actions to share data (in the forms of a file) between jobs in a workflow.
To share variables, you can save the variables in a file with format:
VAR_1=value1
VAR_2=value2
Then download the file from another job and source it to load the variables:
- run: |
sed "" {downloaded_file_path} >> $GITHUB_ENV
shell: bash
Passing by $GITHUB_OUTPUT between jobs
Passing data between caller workflow and called (reusable) workflow
Use on.workflow_call.outputs, called workflow outputs are available to all downstream jobs in the caller workflow.
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