Part 6: Stages and CI

Deploy another stage

pnpm

pnpm alchemy deploy --stage staging

bun

bun alchemy deploy --stage staging

npm

npx alchemy deploy --stage staging

yarn

yarn alchemy deploy --stage staging

The MyEnv environment’s name includes the stage, so staging gets its own environment, app, images and volumes, and changing the image in one stage never reaches another. Your own stage is untouched.

Limit what a stage can spend

src/Sandbox.ts

export const MyEnv = Modal.Environment("MyEnv", {});
export const MyEnv = Modal.Environment("MyEnv", {
  maxConcurrentTasks: 20,
  budget: 50,
});

budget is a monthly limit in US dollars for the environment. Modal stops starting containers when it’s reached.

Keep state in Cloudflare

CI runs start from an empty disk, so store state where every run can read it:

alchemy.run.ts

  {
    providers: Layer.mergeAll(Cloudflare.providers(), Modal.providers()),
    state: Alchemy.localState(),
    state: Cloudflare.state(),
  },

Store the token

Modal has no OIDC federation, so CI uses a token. Create one for a workspace you use only for CI, and add MODAL_TOKEN_ID and MODAL_TOKEN_SECRET to the repository’s secrets.

Deploy per pull request

.github/workflows/deploy.yml

name: Deploy
on:
  pull_request:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    env:
      MODAL_TOKEN_ID: ${{ secrets.MODAL_TOKEN_ID }}
      MODAL_TOKEN_SECRET: ${{ secrets.MODAL_TOKEN_SECRET }}
      CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
      STAGE: ${{ github.event_name == 'pull_request' && format('pr-{0}', github.event.number) || 'prod' }}
    steps:
      - uses: actions/checkout@v4
      - uses: oven-sh/setup-bun@v2
      - run: bun install
      - run: bun alchemy deploy --stage "$STAGE" --yes

Each pull request deploys its own stage, in its own Modal environment, and so builds its own base: a pull request that changes Warm rebuilds it for that stage only.

Clean up closed pull requests

.github/workflows/cleanup.yml

name: Cleanup
on:
  pull_request:
    types: [closed]

jobs:
  destroy:
    runs-on: ubuntu-latest
    env:
      MODAL_TOKEN_ID: ${{ secrets.MODAL_TOKEN_ID }}
      MODAL_TOKEN_SECRET: ${{ secrets.MODAL_TOKEN_SECRET }}
      CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
    steps:
      - uses: actions/checkout@v4
      - uses: oven-sh/setup-bun@v2
      - run: bun install
      - run: bun alchemy destroy --stage "pr-${{ github.event.number }}" --yes

Destroying the stage removes its environment, with its images and the volumes your Worker created in it.