Github Actions - sharing string files between jobs, base64

gh-share-string.md

Github Actions - sharing string files between jobs

Store multiline string as base64 -w 0 job output, and consume in subsequent job.

jobs:
  build:
    runs-on: ubuntu-latest
    outputs:
      envFile: ${{ steps.tempEnvFile.outputs.envFile }}
    steps:
      ... some step that builds .env file
      - name: Cat .env file, encode and save as job output
        id: tempEnvFile
        run: |
          ENV_FILE="$(cat .env | base64 -w 0)"
          echo "envFile=$ENV_FILE" >> "$GITHUB_OUTPUT"
  use-env-file:
    needs: build
    runs-on: ubuntu-latest
    env:
      envFile: ${{ needs.build.outputs.envFile }}
    steps:
      - name: Decode previous job output and save to file.
        run: echo $envFile | base64 -d > .env

Github Actions ubuntu-latest images supports base64 -w 0, disabling column width restriction. This allows a single long string to be later decoded. Watch out for strings that are too long. Max size is 1Mb.

From base64 man page:

‘-w cols’

‘--wrap=cols’

During encoding, wrap lines after cols characters. This must be a positive number.

The default is to wrap after 76 characters. Use the value 0 to disable line wrapping altogether.

‘-d’

‘--decode’

Change the mode of operation, from the default of encoding data, to decoding data. Input is expected to be base64 encoded data, and the output will be the original data.