How to deploy an AWS Amplify app from GitHub Actions?

I want to control Amplify deployments from GitHub Actions because Amplify auto-build

• doesn't provide a GitHub Environment
• doesn't watch the CI for failures and will deploy anyways, or
• requires me to duplicate the CI setup and re-run it in Amplify
• didn't support running a cypress job out-of-the-box

• Turn off auto-build (in the App settings / General / Branches).
• Add the following script and job

scripts/amplify-deploy.sh

echo "Deploy app $1 branch $2"
JOB_ID=$(aws amplify start-job --app-id $1 --branch-name $2 --job-type RELEASE | jq -r '.jobSummary.jobId')
echo "Release started"
echo "Job ID is $JOB_ID"

while [[ "$(aws amplify get-job --app-id $1 --branch-name $2 --job-id $JOB_ID | jq -r '.job.summary.status')" =~ ^(PENDING|RUNNING)$ ]]; do sleep 1; done
JOB_STATUS="$(aws amplify get-job --app-id $1 --branch-name $2 --job-id $JOB_ID | jq -r '.job.summary.status')"
echo "Job finished"
echo "Job status is $JOB_STATUS"

  deploy:
    runs-on: ubuntu-latest
    env:
      AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
      AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
      AWS_DEFAULT_REGION: us-east-1
      AWS_DEFAULT_OUTPUT: json
    steps:
    - uses: actions/checkout@v2
    - name: Deploy
      run: ./scripts/amplify-deploy.sh xxxxxxxxxxxxx master

You could improve the script to fail if the release fails, add needed steps (e.g. lint, test), add a GitHub Environment, etc.

There's also amplify-cli-action but it didn't work for me.