## Host rest api with Starlette: stored input and output artifacts

Deploy a rest api built with Starlette 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 Starlette: 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 Starlette: stored input and output artifacts
- Where can I host REST API built with Starlette?
- 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**  
   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**  
   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**  
   Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

### Prerequisites
- A Starlette 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). 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. 
   ```bash
   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.
   ```bash
   ample logs  --kind build
   ```

### Examples
- **Starlette pattern fixture**  
  Multi-pattern Starlette app whose generated downloads module was checked live.

### Success Checks
1. **App responds on its public URL**  
   **HTTP GET** `/`  
   Expect: ample canary starlette patterns
2. **Generated-downloads self-test**  
   **HTTP GET** `/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 Starlette 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.

### Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: $10.00  
- Basis: size prices from pricing.toml
- **Components**:
  - app server: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.00
  - managed PostgreSQL database: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.00
  - **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

### Evidence Summary
1. **Canary Run**  
   Starlette pattern fixture deployed on Ample; checks passed for generated-downloads and configuration-secrets.
2. **Canary Run**  
   The same Starlette app deployed with a --release-command migration; the marker it created was readable after activation.

### Last Verified At
- Date: 2026-09-21T01:21:36Z

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