## Host ai workflow runner with NestJS: streamed responses

### Summary
Deploy a ai workflow runner built with NestJS on Ample using the streaming response service 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 NestJS: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Not separately tested: your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured; treat the ai workflow runner-specific behavior as your application code.

### Representative Queries
- Host ai workflow runner with NestJS: streamed responses
- Where can I host AI workflow runner built with NestJS?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

### Prerequisites
- A NestJS project that builds and starts with the documented commands (npm install, nest build (TypeScript) then node dist/main.js 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

### 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.

### Workflow Steps
1. **Build and start**  
   `npm install, nest build (TypeScript) then node dist/main.js 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 streaming response service: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). 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  --public`

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

### Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates and NestJS major versions are not verified.
- The ai workflow runner itself (your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.
- **Components**:
  - App server: s-1vcpu-1gb (Monthly Amount: 5.0)
  - Managed PostgreSQL database: s-1vcpu-1gb (Monthly Amount: 5.0)

### Success Checks
- App responds on its public URL (path: `/`, expect: `ample canary nestjs patterns`).
- Streaming-response-service self-test (path: `/p/streaming-response-service`, expect: `an SSE stream: data: id=, then chunk events one interval apart`).

### Evidence Summary
- **Canary Run**: NestJS pattern fixture deployed on Ample; checks passed for streaming-response-service and configuration-secrets.
- **Implementation Revision**: 1d28ae0-dirty (CLI 0.1.21)

### 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 workflow runner](#)  
- [Browse NestJS](#)  
- [Browse Streaming response service](#)  
- [Browse Deploy AI app](#)

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