Migrating Node.js app from Heroku to Fly.io

I recently migrated the Node.js app from Heroku to Fly.io, mainly due to reduced costs.

This blog post will cover the necessary steps in the migration process.

Prerequisites

• Heroku app running

• Use the exact versions for dependencies and dev dependencies in package.json so installation and build steps can pass successfully

• Use the same Node.js version in Dockerfile, package.json, and GitHub Actions workflow

• Use API gateway or custom domain for the service so web apps and mobile apps don't get affected by changing the URL of the service

Migration steps

• Migrate environment variables and secrets

• Migrate the Postgres database with the following commands (the ssl field in database configuration options is not needed)
  

fly secrets set HEROKU_DATABASE_URL=$(heroku config:get DATABASE_URL)

fly ssh console
apt update && apt install postgresql-client
pg_dump -Fc --no-acl --no-owner -d $HEROKU_DATABASE_URL | pg_restore --verbose --clean --no-acl --no-owner -d $DATABASE_URL
exit

fly secrets unset HEROKU_DATABASE_URL

• Migrate the Redis database if it's used

• Include the deployment step in the GitHub Actions workflow

References

• Deploying Node.js apps to Heroku

• Deploying Node.js apps to Fly.io