# Host inventory manager with FastAPI: relational workspace data

Deploy a inventory manager built with FastAPI on Ample using the relational records 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 FastAPI: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing (transitions=true isolation=true). Not separately tested: your record schema, states and access rules; treat the inventory manager-specific behavior as your application code.

## Representative Queries
- Host inventory manager with FastAPI: relational workspace data
- Where can I host Inventory manager built with FastAPI?
- I need a workspace-specific schema, state transitions and access rules.

## Prerequisites
- A FastAPI project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 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**  
   pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   The fixture's module implements relational records: a workspace-scoped table, an explicit state machine (draft to review to published) that rejects invalid transitions, and a cross-workspace read that returns nothing (transitions=true isolation=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 --start "python3 run.py"`

4. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/relational-records) 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 python-3.12 template at s-1vcpu-1gb with the example fixture; other sizes, templates and FastAPI major versions are not verified.
- The inventory manager itself (your record schema, states and access rules) 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.

## Success Checks
- App responds on its public URL: **HTTP GET** on the path `/` should expect `ample canary fastapi patterns`.
- Relational-records self-test: **HTTP GET** on the path `/p/relational-records` should expect `records=ok transitions=true isolation=true`.

## Cost Estimate
Monthly Amount: **10.0 USD**

### 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

## Evidence Summary
- **Canary Run**: FastAPI pattern fixture deployed on Ample; checks passed for relational-records and configuration-secrets.
- **Implementation Revision**: 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21).

## Formats
- **HTML**: [HTML Link](/content/recipes/inventory-manager/fastapi/relational-workspace/index.html)
- **Markdown**: [Markdown Link](/content/recipes/inventory-manager/fastapi/relational-workspace.md)
- **JSON**: [JSON Link](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Ainventory-manager%3Afastapi%3Arelational-workspace)

## 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 Inventory manager**
- **Browse FastAPI**
- **Browse Relational records**
- **Browse Deploy web app**