setup-gmat v0.1 — install NASA GMAT in CI in one step

[djankov]

First release of setup-gmat: a GitHub Action that installs NASA GMAT and bootstraps gmatpy so any workflow can import it. Drop one step into your CI, get a working GMAT_ROOT and an importable gmatpy.

- uses: actions/setup-python@v5
  with:
    python-version: '3.12'
- uses: astro-tools/setup-gmat@v0
  with:
    version: R2026a
    cache: true

What's in v0.1

• Action that downloads GMAT, extracts it, runs BuildApiStartupFile.py, and smoke-checks the install with a one-line gmatpy propagation against a stock sample.
• Inputs: version, cache, python-version. Outputs: gmat-root, gmat-version, cache-hit — plus GMAT_ROOT exported to the workflow environment so subsequent steps see it without reading outputs.
• Install caching via @actions/cache keyed on action major, GMAT version, runner OS, and runner arch. First run is around 5 minutes; cache-hit runs come in around 30 seconds end-to-end.
• Self-CI on ubuntu-latest × R2026a runs two consecutive jobs (cache miss, then cache hit) and asserts the resolved root is byte-identical between runs.
• TypeScript Action, Node 24 runtime, single-file dist/index.js bundle via @vercel/ncc, MIT.

v0.1 supports

Runner	GMAT version
ubuntu-latest	R2026a

Windows + macOS runners and the R2022a / R2025a back-versions are scoped for v0.2.

Pinning

@v0 is the floating major tag — auto-picks v0.x.x patches. Pin to @v0.1.0 for an immutable SHA.

Links

• Marketplace: https://github.com/marketplace/actions/setup-gmat
• Docs: https://astro-tools.github.io/setup-gmat/
• Source: https://github.com/astro-tools/setup-gmat
• Release notes: https://github.com/astro-tools/setup-gmat/releases/tag/v0.1.0

Feedback wanted

• Does the action install cleanly on your ubuntu-latest flavour (self-hosted, ARC, anything non-stock)? If not, which runner image?
• Is cache-hit at ~30 s acceptable for your CI shape, or is that still too long for what you're doing?
• Which v0.2 axis should land first — Windows runners, macOS runners, or the R2022a / R2025a back-versions?