## Host ai chat application with NestJS: worker execution and job state

### Summary
Deploy a ai chat application built with NestJS as a public web service plus a dedicated worker process on Ample. `ample plan --write` discovers both services and their shared database and writes ample.toml; `ample up` reconciles the topology: a managed PostgreSQL 16 database, a public web microVM and a private worker microVM (kind worker, no public URL), both reading DATABASE_URL. Verified on NestJS: a separately deployed worker service (kind worker, no public URL) sharing a declared managed PostgreSQL database with the web service, consuming a jobs table with row locks and marking jobs done once (worker=done attempts=1). Not separately tested: your job payloads, retry policy and scheduling; treat the ai chat application-specific behavior as your application code.

### Representative Queries
- Host ai chat application with NestJS: worker execution and job state
- Where can I host AI chat application built with NestJS?
- I need a separately runnable worker, durable job records and idempotent retries; not a managed queue.

### Resource Requirements
- **Compute**
- **Postgres**

### Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Postgres**: 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
1. A repository with the web app and the worker as separate service directories (the fixture uses apps/web and apps/worker), each building and starting with the documented commands (npm install, nest build (TypeScript) then node dist/main.js on the node-22 template; the worker starts with node worker (its own package.json start script) and binds no port)
2. Both services read DATABASE_URL at runtime and share one jobs table; the worker claims rows with SELECT ... FOR UPDATE SKIP LOCKED and marks them done once
3. An Ample account token with servers:write and databases:write (ample up creates the database)

### Workflow Steps
1. **Plan the topology**
   Run the planner once. It discovers the web and worker services, infers kind = "worker" for the process without a port, declares the database each service needs, and writes ample.toml. Exit 2 means it left questions in the manifest; answer them with --answer or by editing the file.
   Command: `ample plan --write .`

2. **Share one database**
   Keep a single [databases.main] with engine = "postgres", drop any per-service database the planner added, and set DATABASE_URL = { database = "main" } under both [services.web.env] and [services.worker.env].
   Command: `ample plan --offline .`

3. **Apply**
   Reconcile the whole manifest in dependency order: the database first, then both services. It is idempotent and never destructive; exit 0 means everything applied, 2 needs input, 1 a failed resource (independent siblings still proceed and re-running resumes).
   Command: `ample up .`

4. **Verify**
   Fetch the web service URL and its worker status route (/p/worker-queue/status in the example) and confirm the worker processed the enqueued job; on failure read the worker service's runtime logs.
   Command: `ample logs  --kind runtime`

### Limitations
- Verified on the node-22 template at s-1vcpu-1gb for both services with the example fixture; other sizes, templates and NestJS major versions are not verified.
- The ai chat application itself (your job payloads, retry policy and scheduling) is application code and was not separately tested; the worker-queue check is what was verified.
- The worker is a single long-running process supervised in its own microVM; there is no scheduler, cron or horizontal worker scaling in this recipe, and the check ran immediately after deploy so idle behavior of the worker VM is not verified.
- The worker service is private: it has no public URL and is reached only through the shared database; both services are placed with their database.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.
- Region, compliance attestations and request-duration limits are unknown and not claimed.

### Cost Estimate
- **Monthly Amount**: $15.00
- Basis: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
#### Components
- **Web Server**: 1 x s-1vcpu-1gb - $5.00
- **Worker Server**: 1 x s-1vcpu-1gb - $5.00
- **Managed PostgreSQL Database**: 1 x s-1vcpu-1gb - $5.00

**Note**: Always-on monthly price of the tested sizes for the web service, the worker service and the database; apps auto-pause when idle.

### Success Checks
- Web service responds on its public URL
  - Kind: http_get
  - Path: /
  - Expect: ample canary nestjs patterns
- Worker consumed the enqueued job
  - Kind: http_get
  - Path: /p/worker-queue/status
  - Expect: worker=done attempts=1 result=processed-by-worker

### Next Actions
- **Browse the catalog index**
- **Search published recipes by intent, stack and constraints**
- **Prepare a side-effect-free deployment plan for an authorized project**
- **Read the existing agent authentication setup**
- **Browse AI chat application**
- **Browse NestJS**
- **Browse Dedicated worker process**
- **Browse Deploy AI app**