Manage Vercel Lambda with GH Actions

Manage a repository of lambda to be deployed on Vercel

Why ?

This happend when you can't or don't want to go with the Vercel Github integrations, and have a repository with many lambda that need different domain name with their endpoints. You also want to build your own personalized granular steps.

Setup Github Action

Requirement for GITHUB SECRET in settings/secrets/actions:

• VERCEL_TOKEN (to get with scope on your Vercel dashboard)
• VERCEL_ORG_ID (see your vercel project)
• VERCEL_PROJECT_ID (see your vercel project)
• GH_PAT (GitHub Personal Access Token may to help authorized a specific GitHub user)

Use Case

• Deploy the lambda only if some changes was pushed
• Deploy to a different domain if we are on develop or master branch
• Deploy with vercel --dev only when this is a PR
• Deploy with vercel --prod only if the PR is merged
• Have some custom tests inside the GitHub Action

We need 2 vercel projects and get their PROJECT_ID, let's assign them for prod (master) and dev for develop branch.

We can manage each folders inside lamdba with their own githug worlflows .yml. We just need to edit the upper part like so:

name: Deploy Vercel Lambda - lambda-test # here for the name
on:
  pull_request:
  pull_request_target:
    types:
      - closed
    paths:
      - 'lambda/lambda-test/**' # here to trigger only the path who got some changes

  workflow_dispatch:

env:
  LAMBDA_PATH: 'lambda/lambda-test' # here to record the path
  PROJECT_ID_DEV: ${{ secrets.VERCEL_PROJECT_ID_TEST_DEV }} # here as many as needed
  PROJECT_ID_PROD: ${{ secrets.VERCEL_PROJECT_ID_TEST_PROD }} # here as many as needed

We levrage the PROJECT_ID to be dynamicly assigned depending on the branch we will PR on. We used =~ operator to match here the most basic regex.

if [[ ${GITHUB_BASE_REF} =~ "master" || ${GITHUB_BASE_REF} =~ "main" ]]; then
    echo "PROJECT_ID=${PROJECT_ID_PROD}" >> $GITHUB_ENV
elif [[ ${GITHUB_BASE_REF} =~ "develop" ]]; then
    echo "PROJECT_ID=${PROJECT_ID_DEV}" >> $GITHUB_ENV
else
    echo "PROJECT_ID=nope" >> $GITHUB_ENV
fi
echo "BRANCH ${GITHUB_HEAD_REF} FROM ${{ github.base_ref }}"