# Host form collection with FastAPI: data exports

Deploy a form collection built with FastAPI on Ample using the generated downloads 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: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the form collection-specific behavior as your application code.

## Representative Queries
- Host form collection with FastAPI: data exports
- Where can I host Form collection built with FastAPI?
- I need a scoped export format, artifact generation and authorized download procedure.

## Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:s3-compatible-object-storage

## Infrastructure Requirements
### Compute
- **Summary**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

### Postgres
- **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
- **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 generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). 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.
   ```shell
   ample deploy . --name <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/generated-downloads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.
   ```shell
   ample logs  --kind build
   ```

## Success Checks
- **App responds on its public URL**  
  - **kind**: http_get  
  - **path**: /  
  - **expect**: ample canary fastapi patterns

- **Generated-downloads self-test**  
  - **kind**: http_get  
  - **path**: /p/generated-downloads  
  - **expect**: export=ok rows=3 (with ?token=...; 401 without)

## 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 form collection itself (your export formats, retention policy and entitlement model) 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.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: size prices from pricing.toml (loaded by the API) at build revision.
- **Components**:
  - **App server**: 5.0
  - **Managed PostgreSQL database**: 5.0

## Evidence Summary
- **Canary Run**: FastAPI pattern fixture deployed on Ample.
- **Observed At**: 2026-09-21T01:14:18Z

## Next Actions
1. **Browse the catalog index**  
   - **Method**: GET  
   - **Relative Path**: /v1/catalog
2. **Search published recipes by intent, stack and constraints**  
   - **Method**: POST  
   - **Relative Path**: /v1/catalog/search
   - **Parameters**: {"body":{"limit":5,"query":"Host form collection with FastAPI: data exports"}}
3. **Prepare a side-effect-free deployment plan for an authorized project**  
   - **Method**: POST  
   - **Relative Path**: /v1/catalog/plan
   - **Parameters**: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:form-collection:fastapi:data-exports","recipeRevision":"r1"}}
4. **Read the existing agent authentication setup**  
   - **Method**: GET  
   - **Relative Path**: /mcp/setup
5. **Browse Form collection**  
   - **Method**: GET  
   - **Relative Path**: /v1/catalog/nodes/workload%3Aform-collection
6. **Browse FastAPI**  
   - **Method**: GET  
   - **Relative Path**: /v1/catalog/nodes/stack%3Aframework-fastapi
7. **Browse Generated downloads**  
   - **Method**: GET  
   - **Relative Path**: /v1/catalog/nodes/pattern%3Agenerated-downloads
8. **Browse Deploy web app**  
   - **Method**: GET  
   - **Relative Path**: /v1/catalog/nodes/intent%3Adeploy-web-app