## Host mcp server with Flask: streamed responses

### Summary
Deploy a mcp server built with Flask 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 Flask: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway.

### Representative Queries
- Host mcp server with Flask: streamed responses
- Where can I host MCP server built with Flask?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

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

### 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.

### Prerequisites
- A Flask project that builds and starts with the documented commands.
- A PostgreSQL driver reading DATABASE_URL at runtime.
- An Ample account token with servers:write, databases:read.

### Workflow Steps
1. **Build and start**  
   Command: `pip install into .ample/python from requirements.txt`, then `waitress from app.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**  
   Description: The fixture's module implements streaming response service.

3. **Deploy**  
   Command: `ample deploy . --name  --public --start "python3 app.py"`

4. **Verify**  
   Command: `ample logs  --kind build`

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: $10.00
- **Components**:
   - **App server**
       - Size: s-1vcpu-1gb
       - Monthly Amount: $5.00
   - **Managed PostgreSQL database**
       - Size: s-1vcpu-1gb
       - Monthly Amount: $5.00

### Success Checks
1. **App responds on its public URL**
   - Kind: http_get
   - Path: /
   - Expect: ample canary flask patterns

2. **Streaming-response-service self-test**
   - Kind: http_get
   - Path: /p/streaming-response-service
   - Expect: an SSE stream: data: id=, ... done=true|false

### Examples
- **Flask pattern fixture**: Multi-pattern Flask app whose streaming response service module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

### Limitations
- Verified on the python-3.12 template at s-1vcpu-1gb with the example fixture.
- Other sizes, templates and Flask major versions are not verified.
- Apps auto-pause when idle and wake on the next request.

### Evidence Summary
1. **Canary run**: Flask pattern fixture deployed on Ample.
   - Observed At: 2026-09-21
   - Summary: All checks passed.

### Last Verified At
2026-09-21