### Host ai workflow runner with Fastify: Postgres-backed state

#### Summary
Deploy an AI workflow runner built with Fastify on Ample using the durable job state 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 Fastify: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the ai workflow runner-specific behavior as your application code.

#### Resource Requirements
- **Primitive**: Compute
- **Primitive**: Postgres

#### Infrastructure Requirements
1. **Compute**
   - **Status**: verified
   - **Summary**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. **Postgres**
   - **Status**: verified
   - **Summary**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

#### Prerequisites
- A Fastify project that builds and starts with the documented commands (npm install, npm run build --if-present, npm run start 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**
   - Command: `npm install, npm run build --if-present, npm run start 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 durable job state: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Deploy**
   - Command: `ample deploy . --name  --public`

4. **Verify**
   - Command: `ample logs --kind build`

#### Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Fastify major versions are not verified.
- The ai workflow runner itself (your job types, payload schema and retry policy) is application code and was not separately tested; the pattern checks are what was verified.

#### Success Checks
1. App responds on its public URL
   - Path: `/`
   - Expected: `ample canary fastify patterns`

2. Durable-job-state self-test
   - Path: `/p/durable-job-state`
   - Expected: `job=done attempts=1 idempotent=true`

#### Examples
- **Fastify pattern fixture**
   - Description: Multi-pattern Fastify app whose durable job state module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
   - Source Ref: `tests/deploy-canaries/fastify-patterns`.

#### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: Size prices from pricing.toml (loaded by the API)

**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.