# Host Inventory Manager with FastAPI: CSV Imports

## Summary
Deploy a inventory manager built with FastAPI on Ample using the bulk import staging 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, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on FastAPI: a CSV staged as an object, row-level validation with per-row errors recorded, and a restart-safe import keyed by import id (imported=2 rejected=1 restart=ok). Not separately tested: your import format, mapping and conflict rules; treat the inventory manager-specific behavior as your application code.

## Representative Queries
- Host inventory manager with FastAPI: CSV imports
- Where can I host Inventory manager built with FastAPI?
- I need a domain CSV format, row validation, deduplication and an import recovery path.

## Infrastructure Requirements
### Compute
- **Primitive:** 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.

### PostgreSQL
- **Primitive:** 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.

### S3-Compatible Object Storage
- **Primitive:** S3-compatible object storage  
- **Status:** Verified  
- **Summary:** Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

## 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).
- A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables.
- An Ample account token with servers:write, databases:read, buckets: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 bulk import staging: a CSV staged as an object, row-level validation with per-row errors recorded, and a restart-safe import keyed by import id (imported=2 rejected=1 restart=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Wire object storage**  
   Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.

4. **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.
   ```
   ample deploy . --name  --public --start "python3 run.py" --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
   ```

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

## Examples
- **FastAPI pattern fixture**  
  Multi-pattern FastAPI app whose bulk import staging module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## Success Checks
- App responds on its public URL.
- Bulk-import-staging self-test.

## 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 import format, mapping and conflict rules) is application code and was not separately tested.

## 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, monthlyAmount: $5.0)  
  - Managed PostgreSQL database (size: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: $5.0)

## 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.