# Host REST API with FastAPI: Stored Input and Output Artifacts

Deploy a REST API 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 REST API-specific behavior as your application code.

## Representative Queries
- Host REST API with FastAPI: stored input and output artifacts
- Where can I host REST API built with FastAPI?
- I need an input/output artifact contract, object metadata and access boundaries.

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

## Infrastructure Requirements
1. **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.
   
2. **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.
   
3. **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.

## 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 Keep private data in an unpublished bucket.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.
   - **Command**: 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/generated-downloads) from the example; then run your own checks. On failure read `ample logs --kind build` then `--kind runtime`.
   - **Command**: 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 REST API 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 verified.

## Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: 10.0  
- **Basis**: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty  
   - **Components**:
     - **App Server**: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0
     - **Managed PostgreSQL Database**: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0  
 - **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Evidence Summary
- **Kind**: canary_run  
  **Summary**: FastAPI pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template); checks passed for generated-downloads and configuration-secrets. Pattern proof: 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).
  - **Observed At**: 2026-09-21T01:14:18Z  
  - **Implementation Revision**: 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)  
  - **Expires At**: 2027-03-20T01:14:18Z
   
- **Kind**: canary_run  
  **Summary**: The same FastAPI app deployed with a --release-command migration; the marker it created was readable after activation.
  - **Observed At**: 2026-09-20T01:54:51Z  
  - **Implementation Revision**: 199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI e3181f5)  
  - **Expires At**: 2027-03-19T01:54:51Z
   
## Last Verified At
- 2026-09-21T01:14:18Z

## Formats
- **HTML**: [ample.computer/recipes/rest-api/fastapi/artifact-storage](/content/recipes/rest-api/fastapi/artifact-storage/index.html)  
- **Markdown**: [ample.computer/recipes/rest-api/fastapi/artifact-storage.md](/content/recipes/rest-api/fastapi/artifact-storage.md)
- **JSON**: [api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Arest-api%3Afastapi%3Aartifact-storage](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Arest-api%3Afastapi%3Aartifact-storage)