Static environment variables in GitHub Actions

GitHub Actions environment variables have distinct scopes:

• Workflow
• Job
• Step

It’s trivial to set static environment variables in each of these scopes. Dynamically setting environment variables is also possible.

Workflow

Set static workflow environment variables in GitHub Actions by using env: at the top level of a “.github/workflows/ci.yml” file like:

name: ci

env:
  CTEST_PARALLEL_LEVEL: 0
  CMAKE_BUILD_PARALLEL_LEVEL: 4
  CTEST_NO_TESTS_ACTION: error
  CMAKE_GENERATOR: Ninja
  CC: gcc

Job

Static job environment variables are set like:

jobs:

  base:
    runs-on: macos-latest

    strategy:
      matrix:
        cc: [gcc-13, clang]

    env:
      CMAKE_GENERATOR: Ninja
      CC: ${{ matrix.cc }}

Step

Set static step environment variables like:

    - run: cmake -B build
      env:
        CMAKE_GENERATOR: Ninja