## 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.