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Variables

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Learn how to pass data between jobs or steps or set conditionals using variables in EAS Workflows.

Variables can be used in workflows to pass data between jobs or steps. They are useful for conditionals on subsequent jobs or affecting the output of a workflow.

You can set variables in the workflow file with the set-output function:

.eas/workflows/variables.yaml
jobs:
  fingerprint:
    outputs:
      fingerprint: ${{ steps.fingerprint_hash_step.outputs.fingerprint_hash }}
    steps:
      - uses: eas/checkout
      - uses: eas/install_node_modules
      - name: Install additional tools
        run: sudo apt-get update -y && sudo apt-get install -y jq
      - name: Set fingerprint variables
        id: fingerprint_hash_step
        run: |
          FINGERPRINT=$(npx expo-updates fingerprint:generate --platform ios)
          FINGERPRINT_HASH=$(echo $FINGERPRINT | jq -r '.hash')
          echo "Fingerprint hash: $FINGERPRINT_HASH"
          set-output fingerprint_hash $FINGERPRINT_HASH
      - name: Print fingerprint hash
        run: |
          echo "Fingerprint hash: ${ steps.fingerprint_hash_step.fingerprint_hash }"
  existing_build:
    needs: [fingerprint]
    type: get-build
    params:
      fingerprint_hash: ${{ needs.fingerprint.outputs.fingerprint_hash }}
  decide:
    needs: [existing_build]
    steps:
      - name: decide
        run: |
          BUILD_ID="${{ needs.existing_build.outputs.build_id || '' }}"
          echo $BUILD_ID

          if [ -z "${BUILD_ID}" ] ; then
            echo "No build found. Should build."
            exit 0
          fi

          echo "Found build: https://expo.dev/uuid/$BUILD_ID"
          echo "More about build: ${{ toJSON(needs.existing_build.outputs) }}"

In the example above, two things are happening:

  • The set-output function sets the fingerprint_hash_for_steps and fingerprint_hash variables.
  • The outputs keyword on the fingerprint_hash job specifies that the whole workflow will have access to a variable called fingerprint_hash_for_workflow. That variable is later used in the existing_build job to check if there are any existing builds with the same fingerprint.