page:recipes:event registration:next js:relational workflow

Host event registration with Next.js: relational workflow state

Deploy an event registration built with Next.js on Ample using the transactional workflows pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Next.js: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the event registration-specific behavior as your application code.

Prerequisites

• A Next.js project that builds and starts with the documented commands (next build then next start -H 0.0.0.0 -p $PORT on the node-22 template)
• A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
• An Ample account token with servers:write, databases:read

Workflow Steps

1. Build and start
   next build then next start -H 0.0.0.0 -p $PORT on the node-22 template. The server must bind 0.0.0.0 on PORT.

2. Implement the pattern on PostgreSQL
   The fixture's module implements transactional workflows: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. Deploy
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
   Command: ample deploy . --name <app-name> --public

4. Verify
   Fetch the live URL and the pattern self-test route(s) (/p/transactional-workflows) from the example; then run your own checks. On failure read ample logs --kind build then --kind runtime.
   Command: ample logs --kind build

Tested Configuration

• Template: node-22
• Runtime: node
• Size: s-1vcpu-1gb
• Install: npm install
• Build: npm run build --if-present
• Start: npm run start

Cost Estimate

• Currency: USD
• Monthly Amount: $10.0
• Components:
  • App server (size: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.0)
  • Managed PostgreSQL database (size: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.0)
• Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

Success Checks

1. App responds on its public URL (HTTP GET: /, expect: ample canary next js patterns)
2. Transactional-workflows self-test (HTTP GET: /p/transactional-workflows, expect: tx=ok history=2 conflict=rejected)

Limitations

• Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates, and Next.js major versions are not verified.
• The event registration itself (your domain records, validation rules, and concurrency policy) is application code and was not separately tested; the pattern checks are what was verified.