# Host mcp server with Gin: streamed responses

## Summary
Deploy a mcp server built with Gin 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 Gin: 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 mcp server-specific behavior as your application code.

## Framework
Gin

## Workload
MCP server

## Release Status
published

## Support Status
verified

## Execution Status
ready

## Prerequisites
- A Gin project that builds and starts with the documented commands (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build))
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- An Ample account token with servers:write, databases:read

## Tested Configuration
- **Template**: ubuntu-24.04
- **Runtime**: go
- **Size**: s-1vcpu-1gb
- **Build**: CGO_ENABLED=0 go build -o app ./...
- **Start**: ./app

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

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

## Workflow Steps
1. **Build and start**: CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build). The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL**: The fixture's module implements streaming response service: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway...
3. **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
4. **Verify**: Fetch the live URL and the pattern self-test route(s) from the example; then run your own checks.
   - **Command**: ample logs --kind build

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

## Success Checks
- **App responds on its public URL**: app responds on its public URL
- **Streaming-response-service self-test**: streaming-response-service self-test passes with expected data.

## Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-1gb with the example fixture; other sizes, templates, and Gin major versions are not verified.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: size prices from pricing.toml
- **Components**:
  - app server: s-1vcpu-1gb: quantity: 1.0, monthlyAmount: 5.0
  - managed PostgreSQL database: s-1vcpu-1gb: quantity: 1.0, monthlyAmount: 5.0

## Evidence Summary
- **Canary run**: Gin pattern fixture deployed on Ample; checks passed for streaming-response-service and configuration-secrets.

## Unknowns
- region availability is unknown until a verified region fact is recorded
- compliance attestations are unknown; none are claimed.

## Next Actions
- **Browse the catalog index**: GET /v1/catalog
- **Search published recipes by intent, stack and constraints**: POST /v1/catalog/search
- **Prepare a side-effect-free deployment plan for an authorized project**: POST /v1/catalog/plan
- **Read the existing agent authentication setup**: GET /mcp/setup
- **Browse MCP server**: GET /v1/catalog/nodes/workload%3Amcp-server
- **Browse Gin**: GET /v1/catalog/nodes/stack%3Aframework-gin
- **Browse Streaming response service**: GET /v1/catalog/nodes/pattern%3Astreaming-response-service
- **Browse Deploy MCP server**: GET /v1/catalog/nodes/intent%3Adeploy-mcp-server