# Host graphql api with FastAPI: streamed responses

Deploy a graphql api built with FastAPI on Ample using the streaming response service 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 Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Not separately tested: your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured; treat the graphql api-specific behavior as your application code.

## Representative Queries
- Host graphql api with FastAPI: streamed responses
- Where can I host GraphQL API built with FastAPI?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

## Resource Requirements
- `primitive:compute`
- `primitive:postgres`

## Infrastructure Requirements
- **Compute**: Verified
  - Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Postgres**: Verified
  - Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

## Framework
FastAPI

## Workload
GraphQL API

## Release Status
Published

## Support Status
Verified

## Execution Status
Ready

## Prerequisites
1. 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).
2. A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
3. An Ample account token with servers:write, databases:read.

## Tested Configuration
- **Template**: python-3.12
- **Runtime**: python
- **Size**: s-1vcpu-1gb
- **Install**: `python3 -m pip install --target .ample/python -r requirements.txt`
- **Start**: `PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 run.py`

## Input Schema
```json
{
  "name": "string",
  "path": "string",
  "start": "string",
  "env": ["string"],
  "release_command": "string"
}
```

## 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 streaming response service.
3. **Deploy**  
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked).
   ```
   ample deploy . --name  --public --start "python3 run.py"
   ```
4. **Verify**  
   Fetch the live URL and the pattern self-test route(s) from the example; then run your own checks.
   ```
   ample logs  --kind build
   ```

## Examples
- **FastAPI pattern fixture**: Multi-pattern FastAPI app whose streaming response service module was checked live.

## Success Checks
- App responds on its public URL.
- Streaming-response-service self-test.

## Limitations
- Verified on the python-3.12 template; other sizes, templates and FastAPI major versions are not verified.
- The graphql api itself is application code and was not separately tested.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Components**:
  - App server: 5.0
  - Managed PostgreSQL database: 5.0

## Evidence Summary
- FastAPI pattern fixture deployed on Ample.

## 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.